GEOPAK Terrain and Subsurface Modeling v8 1

GEOPAK

Civil Design Software

Terrain and Subsurface ModelingTable of ContentsPart I Digital Terrain Modeling1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Digital Terrain Modeling DTM Tools Stroking Options Extract Tools DATA File Editing Tools Triangulation Display and Draw Features TIN Editing Tools Lattice Model Other Build Tools Volumes, Elevation Differences, and Slope Area Themes Draping Tools Heights and Profiles Visibility DTM Drainage Tools Trace Slope Path DTM Camera Utilities

Part II GeoTechnical Tools1 2 3 4 GeoTechnical Tools Preferences Using GeoTechnical Tools Soil Boxes Via Input Files

1190 N.E. 163rd Street, North Miami Beach, Florida 33162

P.O. Box 1368, North Miami Beach, Florida 33160Phone: (305) 944-5151

Fax: (305)948-6290

GEOPAK _________________________________________________________________________________________

PART I __________________________________________________________________ CHAPTER 1

Digital Terrain Modeling1.1 Overview of DTM FeaturesGEOPAK offers Digital Terrain Modeling components that employ advanced state-of-the-art algorithms and are rich in functionality. GEOPAK DTM features are not limited to triangulated models. Features include: lattice models, contours, interactive editing of TIN files, integrated pads, merged models, surface-to-surface volumetric analyses, thematic analyses, drainage tools, and various utilities. The following sections briefly describe each primary feature.

1.2 Extraction of Input DataDigital Terrain Models can be generated from a wide range of data sources including MicroStation elements, survey data, GEOPAK cross sections, and GeoGraphics project data. An Extract utility is included to facilitate the retrieval and formatting of MicroStation graphical elements. These elements can be classified as contours, random points, break lines, voids, islands, and boundary points. One of the GEOPAK Extract utilities analyzes the MicroStation elements and formulates interpretations. For example, 2D circular arcs can be segmented with elevations interpolated from spot elevations located on the circular arcs and/or upon adjacent elements. Text strings can be interpreted in terms of either the text origin or in terms of the value represented by the text string. A "765.71" text string can be interpreted such that the X and Y coordinates are derived from the origin of the text string and the elevation derived from the "765.71" value represented by the text string. One sample dialog is depicted below.

Digital Terrain Modeling

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Another GEOPAK Extract utility can create DTM input files from various types of ASCII files including: TEX, THD, RT40 and CAiCE. The GEOPAK Survey Manager dialog can prepare an input file for DTM processing directly from survey data. This input file distinguishes between random spot elevations, contours, voids, boundary polygons, break lines and other features. Points stored in a GEOPAK coordinate geometry database may also be utilized via the Survey Manager to create a DTM input for spot elevations. In total, GEOPAK provides the capability to create DTMs from a wide array of data sources.

1.3 Triangulated ModelsThe advanced algorithms employed by GEOPAK are apparent the first time you see the triangulated model display on the screen. Triangles appear from left-to-right in an ordered array; not in a randomized manner as is typical with standard Delauney based algorithms. You will also notice how fast the DTM is calculated. Processing time takes no longer than a few seconds, even for a set of data points numbering in the thousands.

1-2 Part I - Digital Terrain Modeling

___________________________________________________GEOPAKThe triangulated model is stored in a binary file as a triangulated irregular network. For each generated triangle, polynomial coefficients can be calculated and also stored in the binary file. Voids defined during the extraction or editing process can be utilized within a model. No triangles are drawn within the void areas. There is no limit as to the number of voids supported per model. Several routines for interactively editing the triangulated model are provided in the Edit mode. These include editing spot elevations, adding and deleting break lines, all seen on the screen, and, by the push of a button, changed in the binary file, at the user's request. When large models are utilized, the user may select an area of interest (with a Fence placement), displaying only that area. Models, which require additional review or editing, may also be "clipped" to a smaller size model while the original model integrity remains intact. If desired, the "clipped" model may be merged back into the original model, as the user dictates.

1.4 EditingSeveral options are available within the Editing mode, some of which utilize the extracted data file, while others utilize the triangulated model. Utilizing the extracted data file, two reports may be generated: the first will identify duplicate points while the second identifies and optionally displays crossing features, such as break lines or contours. Neither of these reports make any adjustments to the model, they are for informational use only. However, two other features, which do change the extracted data file, are joining and filtering linear features. The joining process is useful when the source break lines or contour lines consist of several elements containing numerous vertices. In these cases, the end of one break line is the beginning of the next break line, so the software distinguishes this as two separate break lines. During the joining process, GEOPAK changes these from the beginning and end of individual elements to the beginning and subsequent shots of one element. In addition to making a small sized model, the best advantage is a more accurate model. The filtering process compares each pair of adjoining vertices on linear features, i.e. break lines or contours. If the horizontal distance between two vertices is less than the tolerance, the software compares the initial two points to the next vertex on the element. If this third vertex is also within the tolerance, the middle vertex is filtered out.


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GEOPAK __________________________________________________________________________________The other editing features utilize the triangulated model and include: Edit spot elevations changes the x, y or z value of a spot elevation, delete or add a spot. Edit lines - this includes deleting a break line, as well as inserting a break or drape line. Edit triangles - deletion of triangles optionally creating a void, or re-triangulating. All these editing features dynamically show the changes as they occur. In addition, the changes are not made permanently to the triangulated model until the user selects the Save button, so the user decides when to change the original model, not the software.

1.5 Lattice ModelsThe lattice model represents a grid mesh draped over the triangulated irregular network. As can be seen in the image below, this creates a very clear visualization of existing ground.

The user controls the density of the lattice grid as well as range and registration of the lattice. The process requires very little processing time.

1.6 ContoursContours may be drawn as line strings or color filled shapes in a thematic manner. As can be ascertained on the dialog depicted below, for string contours the following features may be defined: major and minor contour intervals, maximum and minimum z-ranges,1-4 Part I - Digital Terrain Modeling

___________________________________________________GEOPAKregistration, text labels for both major and minor contours including the level, symbology, and intervals. Contours may be displayed only or written into a 2-D or 3-D MicroStation file. When written, they can be placed in a single graphic group for easy deletion. Areas of interest may be identified with any of the MicroStation fence commands wherein the software can load contours.

A variety of other DTM features can also be drawn or displayed. These include the hull, or outline of the model, triangles, spot elevations, break lines, etc. Each feature can have its own unique symbology, and any combination of features can be drawn or displayed. Utilizing MicroStation fence commands, features within a specified area, rather than the entire model, can be drawn.

1.7 Merged ModelsAny two models may be merged into a third model as long as the two models overlap at a minimum of one point. Both the original and the merged model remain intact. Typical applications of merged models include the superimposition of a proposed roadway onto the existing terrain, or merging of updated terrain onto void areas of the existing terrain.


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GEOPAK __________________________________________________________________________________ 1.8 Volumetric AnalysesSix volume options are available in the Volume Analyses. Three prismoidal volumes are supported, which calculate prismoidal volumes between two surfaces or a surface and a plane. In the prismoidal routines, TIN topology is utilized to determine the triangle intersections on the fly and therefore does not require the time and/or memory resources of the other volume modules. In other modules, cut and fill volumes between two surfaces can be calculated, as well as between one surface and a fixed elevation. Lattice volumes may be computed by utilizing TIN files, then specifying the number of grid points. GEOPAK first lattices, then computes volumes. These volume calculations can be performed across the entire DTM model or on localized portions of the model. One volume dialog is shown below.

Depending on the option utilized, reports can be created in addition to the volume display window above.


___________________________________________________GEOPAK 1.9 Thematic Analyses

Color-coded shading of elevation ranges, slopes and aspects can be applied to either the DTM or lattice models with the Themes dialog. Elevation thematics display elevation ranges. Slope aspects display the steepness of the terrain. For example, the image below depicts the slope thematic where the heavily shaded portion of the model indicates the areas of terrain with a slope less than 25 degrees.

Aspect thematics, on the other hand, permit color-coded displays of portions of the model facing certain directions. Since zero degreesDigital Terrain Modeling 1-7

GEOPAK __________________________________________________________________________________denotes due north, an angle range between 45 and 135 degrees would provide a shaded model of easterly facings.

1.10 DrapingThe draping tool sets the Z-coordinate values of MicroStation elements to correspond to the surface of the triangulated model. Graphic elements can be selected individually, collectively via a MicroStation fence or MicroStation selection sets.

1.11 UtilitiesThe GEOPAK DTM component also includes several utilities to query height, view profiles, review model statistics (number of points, high/low elevations, etc.) as well as interactively review the elevation, slope, and aspect of a given coordinate point. Other Utility features include the ASCII to Binary and Binary to ASCII file conversions utilizing GEOPAK .dat files.

1.12 Drainage ToolsA myriad of drainage tools is supported on the Drainage Tools palette. These include Delineating Watersheds, Sump Lines, Ridge Lines, High Points, Low Points, and Flow Direction. In addition, both Upstream and Downstream Trace are supported.


PART I __________________________________________________________________ CHAPTER 2

DTM Tools2.1 OverviewFeature / Function Project Manager (Road) Tool Invoking the Digital Terrain main tool frame, and subsequently accessing a variety of DTM tools and features. Existing Ground

Menu Application

GEOPAK Road > DTM Tools GEOPAK Site > DTM Tools GEOPAK Bridge > Road Tools GEOPAK Survey: Limited number of tools supported See GEOPAK Survey documentation

All GEOPAK functions are processed from either the GEOPAK DTM tools or the DTM menu bar. To begin, access any MicroStation 3D or 2D file. The DTM menu bar is accessed via the DTM tool frames. Tool frames and tool boxes are supported within GEOPAK in addition to the menu bar options invoking various GEOPAK tools. The tool frame (as depicted below) is similar to the MicroStation main tool frame, is 2x5, not resizable, but dockable.

Each icon in the toolframe is a tool box that one can "tear off" to become a "tool box." The individual tool boxes can be docked and resized. There are ten tool boxes, with the following titles (order down first column, then down second column):

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GEOPAK __________________________________________________________________________________ DTM Menu Extract Edit Load Analysis Stroking Options Build Drape Reports Utilities Each tool box is discussed in subsequent subsections. If the function of an icon is not apparent to the user, position the cursor on the icon. A detailed description is displayed in the status bar and a tool tip appears, as depicted in the graphic below.

These tools remain and reopen automatically even if you exit Microstation, then re-enter later.

2.2 Menu Bar

The DTM Menu tool box (first column, top box) is depicted above and is a single icon, which invokes the GEOPAK DTM menu bar as depicted below.

2.3 Extract


__________________________________________________________GEOPAKThe Extract tool box (first column, second box) is depicted above and contains four tools. These include (from left to right): Extract DGN Data Extract XYZ Data Extract DEM Data Extract Set Format

2.4 Edit

The Edit Tools tool box (first column, third box) is depicted above and contains six tools. These include (from left to right): Edit Triangles Edit Duplicate Points Edit Crossing Break Lines Filter Vertices Join Linear Features Z Range Clip

2.5 Load

The Load tool box (first column, fourth box) is depicted above and contains a single tool, Load DTM Features.

2.6 Analysis

The Analysis tool box (first column, fifth box) is depicted above and contains ten tools. These include (from left to right): Height Query View Profile

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GEOPAK __________________________________________________________________________________ Volumes Elevation Difference Slope Area Themes Drainage Tools Visibility Trace Slope Path DTM Camera

2.7 Stroking OptionsThe Stroking Options tool box (second column, first box) is depicted above and contains a single tool, Stroking Options.

2.8 Build

The Build Tools tool box (second column, second box) is depicted above and contains six tools. These include (from left to right): Build Triangles Build Lattice Merge TINs Clip TIN Build Pad Build Delta TIN

2.9 Drape

The Drape tool box (second column, third box) is depicted above and contains three tools. These include (from left to right): Drape Vertices Drape Vectors Drape Elements2-4 Part I - Digital Terrain Modeling

__________________________________________________________GEOPAK 2.10 Reports

The Reports tool box (second column, fourth box) is depicted above and contains four tools. These include (from left to right): Duplicate Point Report Crossing Break Line Report TIN Statistics Report Lattice Statistics Report

2.11 Utilities

The Utilities tool box (second column, fifth box) is depicted above and contains six tools. These include (from left to right): Convert TIN ASCII to Binary Binary to ASCII Check Triangulation English to Metric Export DTM

2.12 DTM Tool Summary

DTM Menu

Edit TIN

Edit Dup. Points

Edit Break Lines

Filter Vertices

Join Features

Z Range Clip

Drape Vertices

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Drape Vectors

Dup. Point Report

Crossing Break Line Report

Lattice Statistics

TIN Statistics

Elev. Difference

Slope Area

Volumes

Extract DEM

Extract Graphics

Extract Set Format

Extract XYZ

Convert TIN

ASCII To Binary

Binary to ASCII

Check Triangulation

Build Triangles

Build Lattice

Clip TIN

Merge Tins

Load Features

Themes

View Profiles

Drainage Tools

Height Query

English Metric

Export DTM

Build Pad

Build Delta TIN

Visibility

Drape Elements

Trace Slope Path


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DTM Camera

DTM Tools

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GEOPAK __________________________________________________________________________________


PART I_______________________________________________________________CHAPTER 3

Stroking Options3.1 OverviewFeature / Function Tool DTM Menu Bar Settings > Stroking Setting stroking options utilized in the Extraction and TIN editing tools.

Two user-defined values need to be defined before the extraction or TIN editing procedure commences. The Stroking Options dialog is depicted below.

If the source data is mapped in a 3D-design file, Stroking may be applied to the data. Stroking is not available if the data resides in a 2D-design file. Stroking is the process of automatically adding shots to the DTM input (.dat) file by interpolating new shots from the linear and curved sections of the data. Review of the triangles generated from the DTM input files utilizing the various stroking options best illustrates these stroking options. The graphic below illustrates median nose break lines.

Stroking Options

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GEOPAK _______________________________________________________The vertices of the break lines are depicted by the +s. The illustration below depicts the triangles generated from the break lines above utilizing no stroking options.

Activate the Minimum Linear Distance toggle if you wish to densify portions of linear elements. The Minimum Linear Distance is utilized to interpolate new shots from the linear elements. For instance, if survey data was taken approximately every 50 master units and this distance was set to 25 master units, t en a new shot would be interpolated every 25 h master units. In this example, twice as many shots would be used to create the DTM in the linear sections of the break lines. Still utilizing our original median nose, the following graphic depicts the generated triangles when the toggle is activated and the Min. Linear Distance is set to 25. Interpolated vertices have been added whenever the distance between surveyed vertices is greater than 25 master units.

The graphic below depicts the generated triangles when the toggle is activated and the Minimum Linear Distance is set to five. Notice the increased number of triangles due to the increased number of vertices on the linear break lines. Also, note there is no change in the number of vertices in the curved area as the linear toggle has no effect on curves or arcs.


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Activate the Curve Stroke Tolerance toggle to densify the curved portions of the break lines. Curved break lines in GEOPAK are handled by segmenting the curve into small chord segments. The length of the chord segments can be determined by setting the Curve Stroke Tolerance. This distance is used to interpolate new shots along the curved break lines. This value is used as a perpendicular minimum distance from chords generated along the arc. Chords are drawn along the arc and the perpendicular distance is measured from the middle of each chord to the arc. If this distance is larger than the Curve Stroke Tolerance, the process is repeated with a shorter chord length. This process is repeated until the end of the curve is reached. The flatter the curve, the fewer number of points will be calculated. The steeper the curve, the greater number of points that will be calculated. Let's review a few examples utilizing the same median nose. Again, the original break line and generated triangles are illustrated below.

Now if the Curve Stroke Tolerance toggle is activated and the Curve Stroke Tolerance is set to 0.1 master units, the following triangles would be generated. (Note the Linear Distance toggle is inactive for these examples.)

Stroking Options

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GEOPAK _______________________________________________________

Looking at a close-up of the median nose, the following would be viewed on the screen.

Now, let's set the Curve Stroke Tolerance to 0.01. The results for the entire median and the close-up are depicted in the illustrations below.

The Curve Stroke Tolerance and Minimum Linear Distance toggles can be activated simultaneously. The illustration below depicts the same median nose when both toggles are activated.


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In the example above, the Curve Stroke Tolerance was set to 0.01, while the Minimum Linear Distance was five.

Stroking Options

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PART I_______________________________________________________________CHAPTER 4

Extract Tools4.1 OverviewFeature / Function Tools From the Digital Terrain main tool frame, invoke a variety of DTM extraction tools.

The Extract tools create source-input files for the GEOPAK Build Triangles tool from MicroStation graphics (Extract) or several types of ASCII files (ASCII). DEM files can also be utilized. These source-input files are the basis for creation of the triangulated models. Another option utilized during the extraction process is stroking, the process of automatically adding shots to the DTM Input file by interpolating new vertices from linear and curved break lines.

4.2 Extraction of Graphic ElementsFeature / Function Utilizing graphic data, create a source input file for subsequent DTM model generation.

Tool

DTM Menu Bar

Extract > Graphics

Graphic elements in MicroStation 2D or 3D files can be extracted.

Extract Tools

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GEOPAK______________________________________________________________Note: Extraction of elements of specified parameters include all elements visible in a view, within a fence or within a selection set, whether the elements are in the active file or reference files (with locate activated). A view of the Extract Parameters dialog for the Extraction mode is shown below.

The dialog utilizing the second Mode option, Interpolation, is displayed below.


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Whereas the Extraction mode creates a DTM input data file from the coordinate vertices of MicroStation elements, the Interpolation mode must first calculate the elevations for the coordinate vertices of MicroStation elements. The interpolation process is applicable where elevations are not stored with the MicroStation longitudinal reference elements. This occurs when longitudinal reference elements are two-dimensional or threedimensional, but are all drawn at a common elevation. In both of these topographic mapping instances, the spot elevations determine the elevations along longitudinal reference elements. Therfore, the dialog for the Interpolation mode has two sets of Search Criteria, one for the Longitudinal References and a second for the Spot Elevations. Spot elevations can be represented by graphical elements or text. For each MicroStation longitudinal reference element, GEOPAK locates the spot elevations nearest to and on either side of the element endpoint. Then, the elevation at the element endpoint is calculated. For example, the example

Extract Tools

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GEOPAK______________________________________________________________shown below calculates an interpolated elevation of 137.57 from elevations located 10 meters and 25 meters on either side of the element endpoint. Note: The interpolation mode is only valid for Feature Types: Breaks, Contours, and Break Voids. For contours within a 2D file, the associated elevation must be within the Con Z-range, more commonly known as "tagged." Elevations for spot elevations may be determined by textual value (if the origin of the text is the origin of the spot) or "tagged" elevations for other element types, i.e., zero length lines or cells.

The resulting input file includes XYZ coordinates for both source spot elevations as well as for interpolated endpoints. Inclusion of the source spot elevations is mandatory since the spot elevation data often reflects important vertical topological features such as the high and low points along the longitudinal reference. Inclusion of interpolated endpoints is mandatory since the endpoints of longitudinal reference elements define changes in the horizontal topological features. These alterations in the horizontal topology determine break lines. The fields in the dialog are detailed in the table below. File Name File Type: ASCII Binary Name of DAT file to be created. The advantage of the binary format is that input data is loaded much quicker when generating the triangulated model since the point and/or break line data can be read much faster from a binary file than from an ASCII file. However, other than reduced loading time, there are no functional differences between the ASCII and binary files. One advantage of the ASCII file format is that the file may be viewed and/or edited with a text editor. Only valid when the ASCII File option is selected, the number of decimal places displayed within the file ranges from zero to six. The binary option

Decimal


______________________________________________________________GEOPAKplaces displayed within the file ranges from zero to six. The binary option defaults to double precision, with no user options. File Open: Create Append The data file used as input to the DTM process can be created as a new file or the extracted data can be appended to the end of an existing data file. When you type the file name or use the Files button to access a file, the data file is not actually opened until you establish all entries on the dialog and press the Apply button. At that time, GEOPAK creates a new file or opens an existing file depending upon the setting of the File Open option button. If the File Open option is set to Create and the file already exists, an Alert dialog appears with the message "Overwrite existing ?" when the Apply button is pressed. If you press OK, the existing file is overwritten. Pressing the Cancel button permits you to return to the main Extract dialog and readjust the file name or File Open mode. If the Open option button is set to Append and the file does not exist, an Alert dialog appears with the message "Create ?" when the Apply button is pressed. Pressing OK results in the creation of the specified file. Pressing Cancel returns control back to the main Extract dialog. Feature Type: Spots Breaks Boundary Contours Voids Island Graphic Triangle Drape Void Break Void A Boundary is used to constrain the external boundary of the triangulated model. No triangles are created outside the boundary polygon. In addition, any point data outside the boundary polygon is ignored. A boundary polygon must start and finish with the same point. In addition, the boundary polygon must be continuous within the data file. Contours are a special feature intended for use if the source MicroStation elements represent digitized or otherwise created contours. Use of this feature insures the integrity of the contour strata in the Spots are points that have no functional relationship to any other point. Random survey shots in open terrain would be an example of random spots. Point elements such as cells, circles, and text strings are typical MicroStation elements used to define spot elevations. Lines, line strings, and other longitudinal elements are equally valid. GEOPAK simply creates a spot elevation for each vertex of each longitudinal element. Breaks are used to designate linear features such as edges of pavement, ditch bottoms, ridges, etc. Any longitudinal element may be defined as a break line. Circular arcs are automatically segmented by GEOPAK in a manner consistent with the arc radius.

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GEOPAK______________________________________________________________subsequent DTM. Processing of a DTM with contours classified as spot elevations invariably results in a DTM that, if subsequently contoured, will not match the original extracted contours. Void areas are closed shapes to demarcate areas of missing data or obscure areas. No point or break data located within the void area is utilized and no triangles are created inside the void areas. The Void coordinates are included in the triangulation and void lines between successive void coordinates are inserted as drape lines on the TIN surface. Therefore, they do not change the slope or elevations of the TIN surface. Island - used to place triangulated data within a void, i.e., islands in the middle of rivers, lakes, etc. Graphic Triangles - by extracting as triangles, the sides of each triangle, in addition to the vertices are maintainted. If spots are used, the vertices would be utilized but not the triangle sides. Drape Void - In the drape void, the void coordinates are not included in the triangulation. Voids are inserted post triangulation. The void coordinates and lines are draped on the TIN surface. Even though a user must provide an elevation for the Drape Void vertices, the user elevations are changed to the elevation of the TIN surface at the XY Drape Void coordinate position. Break Void - A void utilizes the elevations of each vertex, while the void lines between successive void coordinates are inserted as break lines. Therefore, break voids change the slope and elevations of the TIN surface. Mode: Extraction or Interpolation The Extraction mode determines XYZ data directly from the coordinate values of three-dimensional MicroStation elements. The Interpolation mode, by contrast, derives XYZ data by locating spot elevations on longitudinal MicroStation elements and interpolating. Hence, the Interpolation mode can be applied to both two-dimensional as well as three-dimensional MicroStation files as long as a Z-coordinate reading can be ascertained from the spot elevations. Utilized in the interpolation mode, this shortcut button to the Settings > Stroking dialog may be used. Changing the dialog from either location automatically updates the dialog in the other location. For a detailed discussion, refer to the Settings > Stroking documentation.

Stroking


______________________________________________________________GEOPAKSelect Criteria group box

Before extracting MicroStation elements, a description of the desired elements must be defined in terms of element types, levels, colors, weights and styles. Not every extract operation requires the definition of every parameter; only enough parameters to uniquely differentiate the desired element from all other graphical elements in the MicroStation file. For example, if the elements desired for extraction are only present on level 25, then only the level parameter need be defined. To the left of each parameter label is a toggle. If the toggle for any parameter is deactivated, GEOPAK assumes that the full range of settings for this parameter is available. For example, if the Colors toggle is deactivated, GEOPAK searches for all colors: 0-256. Similarly, a deactivated Colors toggle is equivalent to an activated Colors toggle and a keyin of 0-256. If a toggle is activated and no values given, GEOPAK searches for nothing, therefore, be sure if a toggle is on that values are defined. Level Weight Styles Types Colors If specific parameter settings are to be considered, the toggle must be activated. Once activated, the associated Select button becomes available. Simply toggle on the desired parameter, the press the Select button. The Mask dialog is displayed, wherein the desired parameter settings may be identified. You may select as few or as many parameters to identify the desired elements. When the Type > Cell option is activated, all cells with the other specified parameters (i.e., level, color, weight) are utilized. However, if the Cell option is activated and a cell name is typed into the field to the right of Cell toggle, then only the named cell with the other specified parameters is utilized. For example, if level 40 is specified in the Level Mask, and two cells, SPOT and X are located on level 40, and no cell name is specified in the cell field, then both cells are extracted. However, if SPOT is typed into the field, then only the SPOT cells are extracted,

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GEOPAK______________________________________________________________although other cells are located on level 40. The Text String also has two options: Origin and Content. When the Text String toggle is activated and the option is set to Origin, GEOPAK utilizes the origin of the text as the x, y, z coordinates for extraction. If the Content option is specified, the x, y coordinates are derived from the text origin. However, the z value is not the z value within a 3D file, but the actual value of the text, whether a 2D or 3D file. Match The Match tool is a method of determining and adding the symbology of elements to be extracted to the Mask dialogs. First, activate the desired toggle(s) to the left of the Select Criteria. Then press the Match button. You are prompted to select the desired element. After identifying and accepting the element, its select criteria is added to any criteria whose toggle is activated. In addition, any elements of the specified parameters are highlighted. The Match button can be utilized numerous times to select additional elements. The information is appended to the Mask dialogs until the Reset button in the dialog is pressed, (which clears all active criteria selections). Pressing the Display button displays all elements of the current parameters. The Reset button clears all Mask dialogs, so a new match procedure may commence. If a spot elevation is within 0.75 master units of a longitudinal reference, the software projects the spot onto the reference (perpendicular) element and uses the elevation to interpolate. The View method extracts every element that is visible in the specified active view and satisfies the select criteria. This includes elements in both the active as well as reference files if the Locate is activated. Simply set the desired View number before pressing the Apply button. The Fence method extracts every element that satisfies both the fence criteria as well as the selection criteria defined via the Select Criteria group box. All MicroStation fence options are supported. Place the fence prior to pressing the Apply button. Complex Chain - The Select Criteria group box disappears from the dialog, since you identify the elements via the cursor; and no file-wide searches are involved. Also, notice that the ID Element button appears adjacent to the Extract method option button. This button initiates the

Display

Reset

Tolerance (Interpolation mode only)

Extract Method: View 1, 2, . Fence Complex Chain Selection Set


______________________________________________________________GEOPAK"chaining" of MicroStation elements. The following outlines the sequence of operations associated with the Complex Chain method. 1. Establish the desired dialog settings. 2. Adjust the Extract method option button to Complex Chain. 3. Press the ID Element button. 4. Identify and accept the first element that constitutes the beginning of the chain. Selection of subsequent elements is identical to the operation of the MicroStation automatic create complex chain command. Successive connected elements are highlighted one at a time for inclusion or rejection as long as the endpoint of the next element is within a specified tolerance to an endpoint of the current element. The Tolerance is specified on the MicroStation Automatic Create Complex Chain palette. After the first element is selected and accepted, the next connected element is highlighted. If more than a single element is located within tolerance to the next element endpoint, the message "Fork Accept/reject" appears in the MicroStation prompt field. A data point accepts the highlighted element. Pressing the reset cursor button rejects the highlighted element and highlights another one. Once the end of the chain is reached or the user presses the reset cursor button when no more connecting elements are available, the identification of component chain elements is complete. At the completion of the selection process, the Apply button becomes available. The extraction of elements to a DTM input file commences when the Apply button is selected. Selection Set - This method is identical to the Complex Chain in every aspect other than the actual selection of elements. The Selection Set method employs the MicroStation Selection Set tool to identify the element(s) for processing. This method is particularly useful when selecting a single element or a group of disjointed elements few in number. The following outlines the sequence of operations associated with the Selection Set method. 1. Establish the desired dialog settings.

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GEOPAK______________________________________________________________2. Adjust the Extract method option button to Selection Set. 3. Press the ID Element button. 4. Identify the element(s) comprising the selection set. If more than one element is being selected, the control key on the keyboard must be utilized during the selection process. 5. At the completion of the selection process, the Apply button becomes available. The extraction of elements to a DTM input file commences when the Apply button is selected. Apply Commences the extraction procedure. Note that the dialog should be filled in completely, and the Extract mode selected and applicable fence, view, selection set or complex chain identified prior to pressing the Apply button.

4.3 Extracting ASCII XYZ FormatFeature / Function Utilizing generic ASCII files, create a source input file for subsequent DTM model generation.

Tool

DTM Menu Bar

Extract > XYZ

The Extract ASCII XYZ Format tool supports most any ASCII file containing reduced survey data or even just XYZ data. DTM input files can be derived from a file containing XYZ data with no point codes. Other features include embedded Linking Codes and Feature Codes, support for linking together shots based upon defined chains, support for comments and support for the situation where the user does not have a continuation linking code for each shot but wants these shots connected. Note: These ASCII files need not conform to any particular structure or format other than a requirement that each point entry be restricted to a single row.


______________________________________________________________GEOPAKThe ASCII file should not contain more than one point per row. Similarly, multiple rows should not be required to define a single point code. Within the row containing point code data, virtually no restrictions are placed on the arrangement and separation of survey data. Individual data items (point code, x-coordinate, y-coordinate, z-coordinate, point number) can be arranged in either free form or column formats. In addition, extraneous information may be present in the row and ignored by GEOPAK. Data items in the free form format can be separated by spaces, commas, dashes, etc. Two steps are required to extract ASCII data: 1) Load the ASCII file. 2) Identify how the data items are arranged. When the Extract ASCII XYZ tool is invoked, the dialog depicted below is displayed.

4.3.1 Setting up the ASCII FileThe name of the ASCII file may be typed directly into the input field labeled Input File or may be accessed via the File button. Pressing the File button invokes the standard MicroStation dialog box used for files retrieval. The ASCII file need not be in the current directory. Once the survey file is retrieved, the first few lines are displayed in the list box labeled Contents of File as depicted in the graphic above. GEOPAK requires the following information for each data point: Point Code, X-coordinate, Y-coordinate and Z-coordinate. Other

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GEOPAK______________________________________________________________informational items include Point Number, Linking Code, Chain, DTM, Zone, and combination Linking Code Point Code. The first step in assigning fields is to set the delimiter option button to the correct delimiter separating the free format fields. Various delimiters include the comma, dash, slash, semi-colon and space. If none of these satisfy your needs, you can select the Other field. In response to the Other selection, GEOPAK prompts for the delimiter character. Once the correct delimiter has been specified, the second step is to single click onto a line of data. The individual items fields will appear over the series of option buttons located beneath the list box as shown below.

The third step is to identify the individual fields in the data file as representing either a point code, point number, x-coordinate, y-coordinate or z-coordinate. (An exploded view of the option button is depicted below.)


______________________________________________________________GEOPAK

To accomplish this, adjust the option button to correctly identify the function of each associated field from the survey file. For the sample case shown below, the option buttons appear in the following order: Point Code (PCode), X, Y, and Z.

Yet, another case might involve a considerable number of extraneous entries in the survey file. The data file depicted below contains eleven separate fields.1 N 19805.518 E 22155.758 STA 4+40 ELEV 100.79 PCode PL(B) 2 N 19678.501 E 22223,431 STA 4+40 ELEV 95.020 PCode PL(B) 3 N 19600.521 E 22239.441 STA 4+40 ELEV 134.330 PCode PL(B)

Since the dialog permits the definition of only five fields at a time, we must make use of the Previous and Next buttons to shift the fields right and left. Prior to pressing the Next button, adjust the option buttons to the appropriate settings. The first field represents the point number and, hence, is set to None. The next field contains the letter "N" identifying theExtract Tools 4-13

GEOPAK______________________________________________________________following coordinate as a northing. Hence, the option button below the "N" is set to None. After adjusting the five option buttons and pressing the Next button four times, the dialog would appear as shown below. The X coordinate has now shifted from the fifth to the first option button. Subsequent assignment of the other four option buttons would be None for the station label, station value, and elevation label. The option button below the elevation value would be set to Z as shown below.

Pressing the Next button two more times would permit the definition of the Point Code (PCode).

4.3.2 Informational CodesGEOPAK requires the following information for each data point: Xcoordinate, Y-coordinate and Z-coordinate. Other informational items include Point Code, Linking Code, Chain, DTM, Zone, and combination Linking Code Point Code.

4.3.2.1 PCode or Feature CodeWithin the ASCII file, fields designated as PCodes must correlate with Feature Codes defined in the Feature Setting dialog. These codes are used to determine how the data is utilized with the DAT file creation.

4.3.2.2 Linking Code (LCode)A Linking Code describes how individual spot shots are to be connected. For example, Linking Codes determine if the shots should be connected


______________________________________________________________GEOPAKwith lines, line strings, arcs or curve strings. Supported Linking Codes (also referred to as LCode) are listed below: Begin Line End Line Point on Curve End Curve Continuation Close Figure After one of the options is set to Linking Code, the Linking Code button in the lower right corner is displayed. When pressed, the dialog depicted below appears.

These linking codes instruct the software how to connect various linear features. For example, the first shot of a curb and gutter would be a linking feature of one, based on the Linking Code dialog above. Subsequent shots on the curb and gutter in a tangent section would be twos, if the shots were on curve, the code would be four, etc. Depicted below is a short fragment of data:8 9 10 11 12 17000.0000 18800.0000 17399.4338 17426.2252 17671.0359 20000.0000 21000.0000 20336.1088 20545.4905 20808.7510 900.0000 MID 1 1200.0000 MID 2 914.1539 MID 2 1234.3531 MID 3 1364.5333 MID 1

As seen on the dialog below, the user can associate specific character strings, rather than numeric values, with linking operations on the Linking Code dialog.

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GEOPAK______________________________________________________________

The user has the ability to decide which set of shots should be grouped together as a single chain. As an example, consider the following set of Linking Codes.1 2 3 4 5 6 7 Begin Line Begin Line Begin Line End Line Point On Curve Point On Curve Point On Curve

The diagram below depicts how GEOPAK extracts the data in response to this Linking Code sequence:1 2 5 6 3 4 7

The spot shots designated as Begin Line are connected together until the End Line Linking Code is encountered. A circular arc is fit between the three Point On Curve shots. Now consider a similar set of spot shots where no End Line Linking Code appears. Rather, a Begin Line is immediately followed by a Point On Curve shot.1 2 3 Begin Line Begin Line Point On Curve


______________________________________________________________GEOPAK4 5 Point On Curve Point On Curve

1 3 2 4

5

In this instance, GEOPAK draws a line between points two and three; assuming that point three is a continuation of the chain. As before, a circular arc is fit between the Point On Curve shots. GEOPAK also supports a Close Figure Linking Code as shown below:1 2 3 4 Begin Begin Begin Close Line Line Line Figure

In this case, the Close Figure Linking Code instructs the software to draw a line back to the first point in the chain (Point 1). It is not mandatory for the user to designate a Linking Code for each shot. GEOPAK also supports the concept a Continuation Linking Code. For example, consider a situation where no Chain Name has been defined and chains are created by grouping like PCodes. In the sequence of spot shots, if a Linking Code has been defined for one spot shot, it is not necessary to repeat that Linking Code in a redundant manner for subsequent spot shots. It need only be specified when the Linking Code changes. Similarly, if Chain Names are specified, the Linking Code can be defined for one spot shot and not necessarily repeated for subsequent spot shots

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GEOPAK______________________________________________________________belonging to the same chain. The subsequent shots will be assigned the same Linking Code as the previous shot on the same chain.

4.3.2.3 ChainSometimes the surveyor defines distinct names to designate groups of spot shots that should be connected together in some manner. GEOPAK graphically connects the spot shots with common chain names in the order that they appear in the ASCII files.

4.3.2.4 DTMAnother example of the option buttons is DTM. After one of the options is set to DTM, the DTM Control button in the lower right corner is displayed. When pressed, the dialog depicted below appears.

Eight options are included within the dialog, each having its own Control Code: Do Not Include - Any data, which has this control code, is not included in the creation on the DTM. Include As Spot - Any data, which has this control code, includes the shot as a random spot within the DTM. Include As Spot and Break - This control code includes the data as a spot shot and use its linear feature as a break line. Include As Void - This control code includes the data as a void.


______________________________________________________________GEOPAK Include As Drape Void - This control code includes the x,y data as a drape void, and ascertaining the elevations from the model. Include As Island - This control code includes the data as an island. Include As Boundary - This control code includes the data as a boundary. Include As Contour - This control code includes the data as a contour.

A sample fragment of the data file is depicted below.8 9 10 11 17000.0000 18800.0000 17399.4338 17426.2252 20000.0000 21000.0000 20336.1088 20545.4905 900.0000 MID 1 1200.0000 MID 2 914.1539 TREE 4 1234.3531 SPT 3

In this case, the DTM Control is the last field. Utilizing the information from the dialog above, the first two lines of data would be included as spots and a break line as the DTM control codes are one and two. The third line of data would be excluded from the DTM as its control code is four. The fourth line would be included as a spot shot as its Control Code is three. The DTM treatment options can be either 1) associated with the PCode in the Features Setting dialog 2) designated in a field of the ASCII XYZ file or if no Pcode is given, GEOPAK defaults to all spot elevations.

4.3.2.5 ZonesThe user is also able to assign a field of the ASCII XYZ file to Zones. In this case, each shot would be assigned to a specific DTM zone. When creating the DTM input file, you can designate the zone(s) you wish to include. If desired, you could create separate DTMs for each zone. If there is no zone assignment, GEOPAK will place all shots into Zone 1.

4.3.2.6 Combined Linking Codes and PCodesAnother option is a combination PCode/Linking Code LCode&PCode and functions slightly different that the other features. In this mode, the software will decode a given ASCII character string into its Linking Code and PCode components. Since the composition and length of the LCode&PCode combination field can vary from spot shot to spotExtract Tools 4-19

GEOPAK______________________________________________________________shot, the ASCII field designated as LCode&PCode must appear at the end of the line; i.e., after all of the other options such as X, Y and Z have already been defined. The one exception to this rule relates to the Comments field, which can appear after the LCodePcode, if a Comment delimiter is utilized. First, when the LCodePCode option is selected, and the Linking Code button in the lower right corner of the dialog is pressed, the following dialog appears.

In each field, enter the text string utilized for each Linking Code. Note that only those fields utilized in the data must have entries. In our example, we only have Begin Line (.) and End Line (..) defined as our data has none of the other codes. Below is a fragment of a sample data file.1000 1001 1002 1003 1004 252825.564 252835.354 252841.553 252849.420 252857.567 336994.498 336994.086 336996.280 337004.238 337009.067 100.616000 100.182000 99.4940000 94.5180000 97.5970000 .101 .101 ..101.104 .104 ..104.101

Note that the LCode&PCode sequence is at the end of the line. Since the length of the field is variable, and spaces are supported, GEOPAK utilizes all information from the first LCode&PCode character onward. Therefore, this option cannot be placed in the middle of the file, for example, before the Z coordinates. It would assume everything to the right would be part of the PCode/Linking Code including the Z coordinates. In the data above, the first line is a begin line (based on the . from the dialog above) for PCode 101. Line two is also a begin line for 101. The third line is an end line for 101 and a begin line for 104. Therefore, these three lines would draw a line from the first line, through the second shot and stop and the third shot. At this point PCode 104 begins a line.


______________________________________________________________GEOPAKThe decoding of the combined LCode&PCode is a two step process. First, the user defines a set of Linking Code strings via the Linking Code dialog box. GEOPAK searches for these strings and separates Linking Code strings from the PCodes. For example: LC1 PCode1 LC2 PCode2 LC1PCode1LC2PCode2

The first Linking Code (LC1) is associated with PCode1 and the second Linking Code (LC2) is associated with PCode2 and so on. GEOPAK attempts to pair the Linking Codes and PCodes from left to right. LC1 PCode1 PCode2 LC1PCode1 PCode2 PCode1LC1PCode2

Linking Code (LC1) would be applied to those PCodes that are defined in the Feature Setting dialog with the Linking Code option selected. GEOPAK references the Feature Setting dialog to determine if Linear Features were defined for PCode1 and/or Pcode2. Hence, in the example above, if PCode1 was defined with the Linking Code toggle active while PCode2 was defined with the Linking Code toggle not active, then the Linking Code (LC1) would be applied only to PCode1.

4.3.2.7 CommentsGEOPAK also supports Comments. The comment must be preceded by a specific, user defined delimiter. The user can establish this delimiter via the Comment Delimiter field contained on the dialog whereupon the various ASCII fields are designated. The only condition is that this delimiter must be different from the primary delimiter used to distinguish between the various ASCII fields. Moreover, the Comment Delimiter as well as the content of the comment must be contiguous.

4.3.3 Decision Making ProceduresThe graphic on the next page offers a Decision Tree whereby the user can determine the proper settings on the ASCII XYZ dialog for specific data sets. This Decision Tree is organized in terms of specific data set formats. Primary determinants include the following: Presence of Linking Codes Designation of Chain Names

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GEOPAK______________________________________________________________Gaps: Extract connecting geometry between points belonging to the same Chain or PCode but which are not contiguous in the ASCII file. No Gaps: Do not extract connecting geometry in instances where points belong to the same Chain or PCode but are not contiguous in the ASCII file. Subsections following the Decision Tree detail each of the 15 cases.


______________________________________________________________GEOPAK4.3.3.1 Case 1: No Linking Codes. Individual Spot Shots.This circumstance typically indicates a default condition where PCodes are defined without associated Linking information. In addition, the user should choose the No Chain and PCode w/ Lc on the dialog as shown below.

4.3.3.2 Case 2: Linking Code Present & Separated from PCode. Connect by Chain NamesIn this case, all the XYZ lines that have the same Chain name will be connected. The Chain field in the ASCII XYZ file is designated via the Chain setting on the row of option buttons located at the bottom of the dialog as shown below.

Consider the following example:1 14324.2342 45665.4360 134.53 EP1 2 15354.3434 34525.7827 134.79 EP1 3 15346.4354 35321.9052 135.23 EP2 1 1 1 BL BL BL

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GEOPAK______________________________________________________________4 15544.3455 34054.0412 136.75 EP2 1 BL

This results in a single Chain designated as Chain 1 being drawn between points 1 through 4 as shown below:

4.3.3.3 Case 3: Linking Code Present & Separated from PCode. Connect All Points as Single Chain.In this case, the ASCII data set does not identify a Chain Name, but it is desireable to connect all the shots within the file as one group. The manner in which the points are connected is determined by a defined Linking Code as shown below:

Consider the following example:1 2 3 4 14324.2342 15354.3434 15346.4354 15544.3455 45665.4360 34525.7827 35321.9052 34054.0412 134.53 134.79 135.23 136.75 EP1 EP1 EP2 EP2 BL BL BL BL


______________________________________________________________GEOPAKIn this case as shown below, all points (1 through 4) will be grouped together under one chain.

4.3.3.4 Case 4: Linking Code Present & Separated from PCode. Connect by Linking Codes.Consider a survey that contains a large number of spot shots for a single PCode. In this instance, it might be desirable to avoid connecting all spot shots for this single PCode into one huge chain. Rather, the composition of individual chains is controlled completely by Linking Codes. To obtain this result, the user would employ the Upgrade feature as shown below. With the Upgrade setting, a new chain is defined whenever the program encounters End Line, End of Curve or Close Figure. The would allows the user have many different chains with only few PCodes.


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GEOPAK______________________________________________________________5 14394.2456 45647.4820 134.93 EP1 6 15384.3394 33765.7827 134.77 EP1 BL BL

This data would group together points with the same PCode name. Hence, when a terminating Linking Code is encountered, the name of the chain is upgraded as depicted below: Chain EP1-1 containing points 1 & 2; extract with EP1. Chain EP1-2 containing points 5 & 6; extract with EP1. Chain EP2-1 containing points 3 & 4; extract with EP4.

4.3.3.5 Case 5: Linking Code Present & Separated from PCode. Connect by PCodes.If the ASCII XYZ data does not contain a Chain field, but the user is interested in grouping together data points with the same PCode, this can be accomplished via the dialog settings depicted below:



______________________________________________________________GEOPAKIn this case, all the points that have the same PCode are grouped together as a Chain and the Chain name is identical to the PCode. The resultant chains include: Chain extracted containing points 1 & 4. Chain extracted containing points 3 & 4.

4.3.3.6 Case 6: Linking Code Present & Embedded in PCode. Connect by Chain Names.Linking Codes can be embedding within the PCode definitions. First, consider the situation that the Chain is indicated in the ASCII XYZ file as shown below.

The following comprises a sample data set:1 2 3 4 14324.2342 15354.3434 15346.4354 15544.3455 45665.4360 34525.7827 35321.9052 34054.0412 134.53 134.79 135.23 136.75 EP1 EP1 EP2 EP2 A A A A

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GEOPAK______________________________________________________________All the XYZ lines that have the same Chain Name will be grouped together. This results in a single Chain designated as Chain A being extracted between points 1-4 as shown below. The geometry of the Chain will be determined by Linking Code value embedded into the PCodes EP1 and EP4.

4.3.3.7 Case 7: Linking Code Present & Embedded in PCode. Connect All Points as Single Chain.In this case the user does not have any Chain and wants to place all the shots within the file as one group.

Consider the following example:1 2 3 4 14324.2342 15354.3434 15346.4354 15544.3455 45665.4360 34525.7827 35321.9052 34054.0412 134.53 134.79 135.23 136.75 EP1 EP1 EP2 EP2 A A A A


______________________________________________________________GEOPAKIn this case as shown below, all points (1 through 4) will be grouped together under one chain. The geometry of the Chain will be determined by the Linking Code value embedded into the PCodes.

4.3.3.8 Case 8: Linking Code Present & Embedded in PCode. Connect by PCodes.If the ASCII XYZ data does not contain a Chain field, but the user is interested in grouping together survey points with the same PCode, this can be accomplished via the dialog settings depicted below:

Consider the following example:1 2 3 4 14324.2342 15354.3434 15346.4354 15544.3455 45665.4360 34525.7827 35321.9052 34054.0412 134.53 134.79 135.23 136.75 EP1 EP1 EP2 EP2

In this case, all the points that have the same PCode are grouped together as a Chain. The geometry of the Chain will be determined by the Linking Code value embedded into the PCode.

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GEOPAK______________________________________________________________This results in Chain EP1 containing points 1 & 2 as well as Chain EP2 containing points 3 & 4 as shown below.

4.3.3.9 Case 9: No Linking Codes. Point Connections defined via Chain Names. Gap.A user might have an ASCII XYZ file that contains no Linking Code. However, the shots within the file should be connected together as a series of lines/line strings depending on their PCode names or Chain Names. The intent is to connect the points that have the same PCode name and are part of the same Chain. Since there is no indication of Linking Code within our ASCII XYZ file, all our chain alignments will be restricted to lines or line strings. The user also can define the grouping or chaining of the survey points in many different ways. The user can also decide if he/she would like to introduce a Gap between connected elements within a same Chain. In this case, a Gap would be placed if we move from one set of points with same PCode name to another set of points with different PCodes within the same Chain. The following cases will discuss Gap circumstances. First, we consider the situation where the Chain is indicated in the ASCII XYZ and the user would like to have Gaps between different PCodes. In this case, the PCodes in the Feature Settings dialog should not have their Linking Code toggle active.


______________________________________________________________GEOPAK


In this case, all the XYZ shots that have the same Chain Name are grouped together as a Chain. The Chain Name field assignment will be made via the option buttons located at the bottom of the dialog depicting the ASCII XYZ file. All the points with the same PCode name would be connected together and there would be a gap in the chain between two different PCodes. The result is shown below. Chain A contains points 1 through 4. However, a line would be drawn only between points 1 & 2 and between points 3 & 4 due to the Link w/ Gap designation on the dialog.

4.3.3.10 Case 10: No Linking Codes. Point Connections defined via Chain Names. No Gap.Extract Tools 4-31

GEOPAK______________________________________________________________Lets consider the situation that the Chain i again indicated in the ASCII s XYZ, but the user does not want to have Gaps between different PCodes. In this case, the PCodes in the Feature Setting dialog should not have their Linking Code toggle active.


In this case, all the points that have the same PCode are group together as a Chain and the Chain name is the same as PCode. All the points with the same PCode would be connected together and there would be a Link w/ No Gap in the chain. The result is shown below. Chain A is extracted continuously between points 1 through 4 due to the Link w/ No Gap designation.

4.3.3.11 Case 11: No Linking Codes. Connect All Points as Single Chain. Gap at Change in PCode.4-32 Part I - Digital Terrain Modeling

______________________________________________________________GEOPAKIn this particular case, all the points within the ASCII XYZ file are part of the same Chain as there is no indication of the Chain Name within the ASCII XYZ file. The user should choose the option of No Chain and, in accordance with his/her preference, either select the option of Link w/ Gap or Link w/ No Gap. The dialog below is set to Link w/ Gap.

Consider the following example:1 2 3 4 5 6 14324.2342 15354.3434 15346.4354 15544.3455 14394.2456 15384.3394 45665.4360 34525.7827 35321.9052 34054.0412 45647.4820 33765.7827 134.53 134.79 135.23 136.75 134.93 134.77 EP1 EP1 EP2 EP2 EP1 EP1

All points are grouped together under one chain and there is a gap between sequential PCodes.

The resulting chain runs continuous within a consistent PCode. Due to the Link w/ Gap setting, links are not extracted between successive spot

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GEOPAK______________________________________________________________shots with differing PCodes. Hence, line segments are not extracted between points 2 & 3 as well as between points 4 & 5.

4.3.3.12 Case 12: No Linking Codes. Connect All Points as Single Chain. No Gap at Change in PCode.As with the previous case, all the points within the ASCII XYZ file are part of the same Chain as there is no indication of the Chain Name within the ASCII XYZ file. Hence, the user should choose the option of No Chain. However, in this instance, it is desirable to connect the entire set of points necessitating the selection of the Link w/ No Gap option.


In this case, all points are connected together without any gaps. The result is a continuous stream of connecting points.


______________________________________________________________GEOPAK

4.3.3.13 Case 13: No Linking Codes. Connect Points by PCodes. New Chain Element at Change in PCode.With this case, a new series of connected elements begins at every change in the PCode. It might be desirable to upgrade the name of the chain whenever a new PCode has been encountered. For example, the first series of points associated with the EP1 PCode would be called chain EP1-1. The second series of points associated with the EP1 PCode would be called chain EP1-4. To accomplish these results, we would choose the option of Upgrade from chain option button. In this particular instance, we would also choose the option of Link w/ Gap.


In this case, points that have the same PCode name would be grouped together.

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GEOPAK______________________________________________________________

4.3.3.14 Case 14: No Linking Codes. Connect Points by PCodes. Single Chain Element for PCode. Gap.In this case, all the points with the same PCode would be connected together and there would be a Gap in the chain if all the shots with the same PCode name are not listed sequentially in the ASCII XYZ file.


This dataset would create two chains: Chain EP1 consisting of points 1-2,56 and Chain EP2 consisting of points 3-4. The extraction would include a line from 1 to 2 and a line from 5 to 6 with a gap between points 2 and 5. Chain EP2 would extract a line between points 3 and 4.


______________________________________________________________GEOPAK

4.3.3.15 Case 15: No Linking Codes. Connect Points by PCodes. Single Chain Element for PCode. No Gap.In this case, all the points that have the same PCode are going to be part of the same Chain and the Chain Name will be identical to the PCode name. Moreover, all of the points with the same PCode would be connected together due to the No Gap setting.

Consider the following dataset:1 2 3 4 5 6 14324.2342 15354.3434 15346.4354 15544.3455 14394.2456 15384.3394 45665.4360 34525.7827 35321.9052 34054.0412 45647.4820 33765.7827 134.53 134.79 135.23 136.75 134.93 134.77 EP1 EP1 EP2 EP2 EP1 EP1

In this case, all the points that have the same PCode are going to be connected together and will be part of the same Chain. This data set would extract two chains: Chain EP1 consisting of points 12,5-6 and Chain EP2 consisting of points 3-4. The extraction would include a line from 1 to 2, a line from 2 to 5 (due to the Link w/ No Gap

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GEOPAK______________________________________________________________setting), and a line from 5 to 6. Chain EP2 would extract a line between points 3 and 4.

4.3.4 Feature SettingWhen the Feature Setting button is pressed, the dialog depicted below is displayed.

Standard File commands are supported in the upper left corner of the dialog. These support saving settings for repeated use in subsequent sessions. The dialog has a list box, plus fields for Feature Code, Linking Code, DTM Control, and On Chain. The options within the Feature Setting dialog, combined with the options on the main dialog itself, present a wide variety of options to suit most every need. A prudent review of the various cases is warranted before creating and / or editing the settings. See the previous subsections for a detailed discussion.

4.3.5 Additional FieldsTwo toggles are supported in the lower left corner of the dialog:


______________________________________________________________GEOPAK Apply Best Match Feature Code Display Alert Box for Errors When the Apply Best Match Feature Code toggle is active, the best match feature from the Feature Settings dialog is utilized. This option allows placement of one feature in the Feature Settings dialog per item and locates derivatives of that feature in the field. For example, assume that feature 3001 is the EP for Edge of Pavement, but in the field, three different EPs need to be located and chained together. The different EP chains can be located as 30011, 30012 and 30014. During the mapping process, these features will be matched to the EP feature 3001 in the database. Therefore, the user does not have to define multiple EP features in the database. During processing, if impossible extraction or geometrics are attempted, an error message is displayed on the screen if the Display Alert Box for Errors toggle is activated. The error information is always written to the Error Report regardless of the status of this toggle. Another field in the lower center of the dialog is the Output File Format: Binary or ASCII. Although binary files process faster, there is no other functional difference. The ASCII file can be reviewed via any text editor, while a binary file may not. To commence processing, press the Process bar at the bottom of the dialog. The result of this processing is a GEOPAK DAT file, which subsequently can be utilized to generate a DTM with the Build Triangles tool.

4.4 Extracting DEM FormatFeature / Function Utilizing specialized Digital Elevation Models (DEM files) generated from other software programs, create a source input file for subsequent DTM model generation with the Build Triangles tool.

Tool

DTM Menu Bar

Extract > Extract DEM

When the Extract DEM tool icon is selected, the dialog depicted below opens. In addition to reading DEM files and creating a DAT file,

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GEOPAK______________________________________________________________conversions to other coordinate systems can be performed simultaneously, so the output can be in a different system from the input. In addition to the standard DEM input, DTED directories and files, and SDTS are also supported. The DEM option is selected by activating the DEM toggle in the center part of the dialog. One sample dialog is depicted below. Note the File and Point options are discussed in the Geodetic Conversions online help and therefore are not repeated herein.

The Geodetic Conversion tool performs many of the common computations encountered when working with geodetic and grid coordinate systems. Points can be individually entered and converted or multiple points from a coordinate geometry database (GPK file) can be converted via batch mode. All output is directed to an ASCII report file, in addition to a resizable output window.

4.4.1 Conversion OperationsA wide variety of conversion operations are supported including: converting latitude and longitude to grid coordinates. converting grid coordinates to latitude and longitude. converting grid coordinate from one zone to grid coordinates in another zone.


______________________________________________________________GEOPAK converting grid coordinates from one system to another system. Note that both systems must have a common ellipsoid. computing grid scale factor and convergence angle for grid coordinates. computing geodetic forward and back azimuth and distance between two geodetic positions. Computing grid azimuth and grid distance in addition to geodetic forward and back azimuth and distance between two points in the same zone. Computing the line grid scale factor and combined scale factor if elevation data is entered.

4.4.2 Supported Systems and ProjectionsSeveral common systems and projections are supported including the following: HPGN State Plane 1983 State Plane Coordinate systems (all zones) 1927 State Plane Coordinate systems (all zones) Universal Transverse Mercator system (all zones, northern and southern hemisphere) Latitude / Longitude User-defined zones based on either the Lambert Conformal or the Transverse Mercator projection. Variety of ellipsoids are supported for the user-defined and UTM projections. New Zealand Map Grid (1949) New Zealand Local Circuits (1949) New Zealand Local Circuits (2000)

Three options are supported for the Vertical Datum: Not Defined NAVD 88 NAVD 29

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GEOPAK______________________________________________________________

4.4.3 File MenuThe upper right corner of the dialog has standard File options as detailed in the table below. However, the desired output is the Output Data File, therefore the File Menu is not utilized in this application.

4.4.4 User Defined Systems MenuThree options are supported on the User Defined Systems pulldown: User defined projections Used defined ellipsoids Set NTv2 Grid Files

Additional information on these systems is available in the Geodetic Conversion online help.

4.4.4 Using DEM Files to Create a DAT FileOther data sources utilized in the Geodetic Coordinate conversions tools are the various DEM formats including DEM, SDTS, and DTED. A Digital Elevation Model (DEM), consists of a sampled array of elevations for ground positions that are normally at regularly spaced intervals. The basic elevation model is produced by or for the Defense Mapping Agency (DMA), but is distributed by the USGS, EROS Data Center, in the DEM data record format. A wealth of information on DEM formatted data can be obtained from www.usgs.gov. When the DEM option is selected in the center section of the dialog, the dialog changes to reflect the selection. One sample dialog is depicted below.


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Within the Input DEM File group box, the data format is selected. The group box changes based on the selection. Once the selection is made, the File Name may be typed in, or selected via the Files button. Each format is discussed in subsequent sub-sections. Once the file is read, the DEM Coordinate system group box is populated automatically. Therefore, the DEM Coordinate System group box is display only and the values cannot be edited. The Output Coordinate system box includes System type, Ellipsoid, and Zone. As each system is selected, the ellipsoid and zone unghost as needed. For example, when 1983 State Plane is selected, the Ellipsoid is ghosted, however, a Zone must also be selected from the list.

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GEOPAK______________________________________________________________When Latitude / Longitude option is selected, the Zone field is not present, however, the Ellipsoid is unghosted, as depicted in the sample below.

The Vertical Datum options include NAVD88, NAVD 29 or may be Not Defined. Supported Horizontal and Vertical Units include Meters, U.S. Ft., and Int'l Ft. The Output DAT File group box has a single key-in field for the file name of the DAT file to be created. This file can be used within the Build Triangles dialog in the DTM tools. Manually enter the file name or select via the File button.

When the dialog is completely populated, press the Apply button in the center bottom of the dialog to commence processing.

4.4.4.1 DEM FormatWithin the Input DEM File group box, the display fields are initially blank. Pressing the Inquire DEM button, the software scans the DEM file and determines the Number of Points and approximates the size of the Output DAT File. One sample dialog is depicted below.


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The other field in the Input DEM File is the Filter Points. In very large DEM files, the user may choose to filter out some of the grid points, as the density may be too intense. The options are displayed in the exploded view below.

If the Every Other option is selected, the Number of Points is divided in half, while the Output DAT File Size decreases accordingly. If Every Tenth option is selected, the original number of points decreases by 90%. If Custom is selected, a key-in field is displayed and the user can specify the desired filtering factor.

4.4.4.2 SDTS Format

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GEOPAK______________________________________________________________Unlike a DEM file, SDTS consists of multiple files. All the files need to be in the same directory. Notice that the prompt for SDTS asks for a directory, not a file. Therefore, choose the directory where these files are located. When the directory is defined, GEOPAK determines the SDTS Name(s) from the directory. If multiple Names are found, they are listed in the combo box for the user to select the desired Name. The graphic below depicts the single file option. As in the other Input DEM File formats, pressing the Inquire button scans the specified file and populates the Number of Points and approximated Output Data Size in addition to the DEM Coordinate System group box.

4.4.4.3 DTED File or Directory FormatDTED stands for Digital Terrain Elevation Data. It is a DEM type format created by NIMA, the National Imagery and Mapping Agency. The Level 0 data can be downloaded free from the following site, http://geoengine.nima.mil. Level 0 data is a grid typically in 30X30 seconds or 30X60 seconds (latitudeXLongitude). GEOPAK supported options include either DTED File or DTED Directory. DTED File is used to convert a single DTED file. A DTED file typically has


______________________________________________________________GEOPAKan extension of .dtX, where X is either 0,1,2 depending on the type of DTED. The following dialog illustrates the DTED directory option. This option is used when the user wants to convert an entire DTED directory structure. This directory structure is of a distinct format and contains certain type files and directories, as illustrated below.

When downloading data from the official NIMA site, this is the format the data arrives in. The graphic below depicts the single file option. As in the other Input DEM File formats, pressing the Inquire button scans the specified file and populates the Number of Points and approximated Output Data Size in addtion to the DEM Coordinate System group box.

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4.5 Extract Set FormatFeature / Function Utilizing specialized ASCII files generated from other software programs, create a source input file for subsequent DTM model generation.

Tool

DTM Menu Bar

Extract > Set Format

The dialog is depicted below.


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The Input ASCII File must be keyed in. In lieu of typing, pressing the Files button invokes the Input File dialog, wherein the desired file may be selected. The Output File keyin field requires the name of the DTM Souirce Input (.dat) file to be created. It may also be selected via the Files button. The four supported modes are: TEX, THD, CaiCE, and RT40. As the mode is selected, the dialog fields change to reflect the selection. Pressing the Apply button commences the procedure. As seen above, the TEX format requires the GEOPAK Job Number. The THD mode is depicted in the dialog below. This format also requires the Job Number.

The RT40 mode is depicted below. In this format, both Job Number and Chain are required. Pressing the Chain button invokes the Chain Selection dialog, wherein the desired chain may be selected.

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GEOPAK______________________________________________________________The CAiCE mode is depicted below. In this mode, the Output Format is specified as DTM Input. No Chain or Job Number is required, simply the Input File and Output File names.

4.6 DAT File FormatWhen a Binary formatted DAT file is created, the user has no means of reviewing the data outside of GEOPAK. However, when an ASCII formatted file is generated, the file can be viewed, modified, or even created within any ASCII text editor. Note: If the data is collected or created in the ASCII format described below, no extraction processing is required. The user may skip the extraction and proceed directly to the triangulation procedure. Data input elements (records) can represent random spot elevations, break lines, voids, contours, or boundary polygons. The type of element is defined by a feature code. Each input record consists of the feature code field, coordinate fields and the elevation field: Feature Code (integer value) X Coordinate (decimal value) Y Coordinate (decimal value) Elevation (decimal value) A sample fragment from the ASCII input file is shown below: 1 17381.651 22324.071 391.600 1 17383.071 21997.581 332.850 2 17404.721 21621.311 440.890 3 17405.041 22319.311 382.380 3 17427.411 21907.411 297.200


______________________________________________________________GEOPAKThe format in the file is quite simple: a feature code followed by X, Y and Z coordinate values in succession. A single point record occupies each line of the ASCII file. Spaces serve as delimiters between individual fields. The feature code is mandatory and informs GEOPAK how to interpret the input records. The following are valid feature code values and associated descriptions. Feature Code 1 2 3 4 5 6 7 8 9 10 13 14 15 16 Random Spots Start of Break Line Subsequent Point(s) on a Break Line Boundary Polygon Point Start of Contour Line Subsequent Point(s) on a Contour Line Start of a Void Subsequent Point(s) of aVoid Start of an Island Subsequent Point(s) of an Island Start of a Graphic Triangles Subsequent Point(s) of a Triangle Start of a Drape Void Subsequent Point(s) of a Drape Void Function

Random Spots are points that have no functional relationship to any other point. Random survey shots in open terrain would be an example of random spots. Break Lines designate linear features such as edges of pavement, ditch bottoms, ridges or valleys. The first point in a series of connected break lines has a feature assignment of "2." The second and subsequent points along the break line have a feature code of "3." Break line data must be continuous within the data file. A Void delineates an area of no data or an obscured area and is defined by a series of points forming a closed element. The elevations of the void

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GEOPAK______________________________________________________________are incorporated into the data file. In addition, the void must be contiguous within the data file. A Boundary Polygon is used to constrain the external boundary of the triangulated model. All points along the boundary polygon are assigned a feature code of "4." A boundary polygon must start and finish with the same point. In addition, the boundary polygon must be continuous within the data file. A Drape Void delineates an area of no data or an obscured area and is defined by a series of points forming a closed element. It differs from a Void in that the elevations of the void elements are not incorporated into the data file. Rather, the drape void elements are draped onto the model, and model elevations are utilized. The drape void must be contiguous within the data file. An Island is a closed element completely encompassed within a Void. Random spots, breaks and contour elements may be present within the island. Graphic Triangles are 3D triangles placed at true elevations. Since GEOPAK ignores any additional fields past the fourth field (Z Coordinate), extraneous data such as comments or point code information can be included in the file for reference or use with other software or GEOPAK components.


PART I __________________________________________________________________ CHAPTER 5

DAT File Editing Tools5.1 OverviewFeature / Function Tools Generate reports and / or edit the DAT File prior to generating the triangulation model.

A wide variety of DAT file editing tools are supported within GEOPAK. It is preferable to edit prior to creating the TIN model. If the TIN model needs to be regenerated, all TIN editing changes are lost. However, if changes are made to the DAT file are made, and the Tin model is regenerated, the changes are utilized within the TIN generation. Two reports can be generated: Report Duplicate Points - reports duplicate points, i.e., those with coincident x, y coordinates. Report Crossing Features - reports intersecting break lines or contours. Both reports utilize the extracted data file (*.dat), however, they do not make changes to the file. Hence, they are simply reporting functions. The Join Linear Feature is useful when the source break line or contour line consists of several elements containing numerous vertices. In these cases, the end of one break line is the beginning of the next break line, so the software utilizes this as two separate break lines. During the Joining process, GEOPAK changes these from the beginning and end of individual elements to the beginning and subsequent shots of one element. The Filter Data File features tool removes vertices from break or contours lines when located within the specified tolerances of another vertex. The Data Z Clip filters the data file to include (or exclude) data based on elevations.

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Documents

GEOPAK Terrain and Subsurface Modeling v8 1