Vector Data Vector Data AnalysisAnalysisChapter 10Chapter 10

IntroductionIntroduction

Varies with disciplineVaries with discipline Raster vs vector ongoing questionRaster vs vector ongoing question

BufferingBuffering

ProximityProximity Buffer points, lines, polygonsBuffer points, lines, polygons Can have varied buffer based on dataCan have varied buffer based on data ExamplesExamples RingsRings Dissolved buffersDissolved buffers Analysis techniqueAnalysis technique

Map OverlayMap Overlay

Map overlay combines the geometry and Map overlay combines the geometry and attributes of two feature maps to create attributes of two feature maps to create the output.the output.

Input and overlay.Input and overlay. Must be same coordinate system and Must be same coordinate system and

zone, same datum.zone, same datum. Multiple combinations as a process.Multiple combinations as a process.

Feature Type and Map Feature Type and Map OverlayOverlay

Point-in-polygonPoint-in-polygon Line-in-polygonLine-in-polygon Polygon-on-polygonPolygon-on-polygon

Map Overlay MethodsMap Overlay Methods

Our old friends UNION, INTERSECT and Our old friends UNION, INTERSECT and IDENTITYIDENTITY

UNION preserves all map features from UNION preserves all map features from both the input and overlay map. Logical both the input and overlay map. Logical OR.OR.

INTERSECT preserve only those INTERSECT preserve only those features that are common to both input features that are common to both input and overlay map. Logical AND.and overlay map. Logical AND.

Map Overlay MethodsMap Overlay Methods

IDENTITY preserves only map features IDENTITY preserves only map features that fall within the area of the input map. that fall within the area of the input map. Logical AND/OR. Input map AND Logical AND/OR. Input map AND overlay or input.overlay or input.

SliversSlivers

Slivers and fuzzy tolerance.Slivers and fuzzy tolerance. Minimum mapping unit.Minimum mapping unit.

Error Propagation in Map Error Propagation in Map OverlayOverlay

PositionalPositional Identification Identification Error quantificationError quantification

Distance MeasurementDistance Measurement

Closest Closest ArcView = Assign Data by LocationArcView = Assign Data by Location ARC/INFO = NEAR and ARC/INFO = NEAR and

POINTDISTANCEPOINTDISTANCE

Map ManipulationMap Manipulation

ArcView uses GeoProcessing extension ArcView uses GeoProcessing extension to DISSOLVE, CLIP and MERGEto DISSOLVE, CLIP and MERGE DISSOLVE is simplificationDISSOLVE is simplification CLIP is cookie cutterCLIP is cookie cutter MERGE combinesMERGE combines

Map ManipulationMap Manipulation

ARC/INFO uses RESELECT, ELIMINATE, ARC/INFO uses RESELECT, ELIMINATE, UPDATE, ERASE, and SPLITUPDATE, ERASE, and SPLIT In addition to DISSOLVE, CLIP, MERGEIn addition to DISSOLVE, CLIP, MERGE RESELECT creates new coverage based on logical RESELECT creates new coverage based on logical

expressionexpression ELIMINATE creates new coverage by removing ELIMINATE creates new coverage by removing

features defined by logical expressionfeatures defined by logical expression UPDATE is cut and pasteUPDATE is cut and paste ERASE removes features within erase coverageERASE removes features within erase coverage SPLIT is opposite of merge, breaking into two or SPLIT is opposite of merge, breaking into two or

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