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Andrea Scianna DIRAP – University of Palermo – Italy
Andrea Scianna DIRAP – University of Palermo – Italy
Goals
This work is aimed to:
• definition of an interoperable and multi-scale cartographic model, both for urban planning and management of risk events, accordingto a national project (PRIN2004) titled ‘Evolution of cartography for GIS and WEB-GIS applications’;
• creation of GIS and WEB_GIS applications for management of group of public buildings (university campus, hospitals, sports ground, etc.) and related infrastructures.
Andrea Scianna DIRAP – University of Palermo – Italy
Guidelines
Guidelines of whole national project are:
• finding best solutions to improve quality standards for numerical cartography in the Italian contest;
• defining criteria for generalization of multi-scale cartography;
• developing a model of 3D vector cartography;
• investigating methods for structuring numerical interoperable cartography, both for Internet Web applications and as traditional exchange format too;
• experimenting the application of the cartography structure on real cases study;
• writing a GIS model to be used either on commercial and open source software .
Andrea Scianna DIRAP – University of Palermo – Italy
Methodology
Methodological approach is based on:
• the analysis of existing 3D GIS models;
• a comparison between the theoretical enunciation of different analyzed international models and applications actually derived from them.
On this basis, our model has been developed taking also in account some requirements of national traditional cartographic standards.
The new model comprises both the innovative aspects of interoperability, based on a structure with 3D contents, and more traditional thematic content with emphasis on aspects of urban planning and management of risk situations.
Andrea Scianna DIRAP – University of Palermo – Italy
Methodological aspects3D cartographic
structure3D topological
structureImplementation
approach
Comparison between proposals
Analysis of someproposals
In Italy In Europe
Analysis of main3D topological models
Selection of a suitabletopological models
Analysis of 2Dtopological functionalities
Check of featuresof many formats
Analysis of filesstructure
Analysis of mainfunctions
Data managementin DXF, GML3, etc.
commercial open
Exchange formats Softwareimplementation
Selection of a fewGIS software
Identification of mainexchange formats
In Europe
Definition of a new cartographic model
At medium and large scale
Andrea Scianna DIRAP – University of Palermo – Italy
Main steps
1. analyzing characteristics of the most diffused formats in Europe for geographical data interchange;
2. performing tests on different GIS software in handling DXF and GML, to investigate their capabilities to manage geometrical and topological structures, as well as 3D and geographical data;
3. analyzing various proposal for structuring numerical cartography;
4. definition of the cartographic model;
5. building of a software capable to handle geographical data, able to produce cartography, structured in GML 3 format;
6. building of a three-dimensional visualization software, that allows exporting and importing cartography in several formats (not started).
Andrea Scianna DIRAP – University of Palermo – Italy
Is GML standard the answer to our needs?
• GML 3 is suitable to define 3D objects.• The structure can handle semantic data with respect to CAD
interchange format as DXF.• It is possible to structure information at different level of detail (not yet
implemented at this stage in our model).• GML files relating to the whole geographic database are very large, but
transferring of blocks of data with complex topological structure using streaming techniques is allowed.
• There are great flexibility and freedom in the implementation ofschemas, that however cause many problems about interoperability(saving and reading with existing GIS software is not always possible).
• Geospatial data encoded in GML format can be downloaded and uploaded from clients by multiple Web Feature Services.
Andrea Scianna DIRAP – University of Palermo – Italy
Cartography requirementsNumerical cartography must satisfy a large number of purposes and it has to be provided with specific features to make it suitable for certain uses.
fundamental for the tasks that it
must accomplish to
Nominal scale
Topology support
Generalization
3D support
LBS support
data must be topologically structured to be used
or processed in advancedapplication
two types of generalization,
named “first level”
and “second level”
presence of thirddimension is useful
both for visualization and
analysis, for geoprocessing
and computation (like volume calculation,
visibility charts, cost's evaluation,
etc.)
the way to structure multiscale
cartography has a great influence over the creation
of LocationBased Systems
Andrea Scianna DIRAP – University of Palermo – Italy
Main national Italian standard proposal, called “IntesaIntesa GIS GIS model” (IntesaStato Regioni Enti-Locali) has been examined: this cartographic model was written by a working group composed of several members of the main public Italian bodies.
Using this model it's impossible to directly define objects with three dimensions, or volumes: surface are represented in two dimensions only, but there is an “hybrid” way to model 3D surfaces, using a class of spatial attribute called “B3D surface”, that is constituted by a 2D surface joined with a 3D ring that is the boundary of the surface. Level of detail are not defined.
Analysis of existing models
“CityGMLCityGML” is another of examined model: it’s a very interesting cartographic model, mainly oriented to structure 3D models of cities.It is an application profile for GML3 which encodes a multi-level representation of cities, also including elevation, vegetation, water bodies, city furniture and more. Among its characteristics: the use of “Level of details”, that allows use of cartography from a medium to a building scale; topological rules joined with geometrical ones; use of textures (derived from X3D) whose definition is not present in GML standard.
Andrea Scianna DIRAP – University of Palermo – Italy
After evaluation of existing models and cartographic needs, a model hasbeen defined in draft format: this model attempts to put together the requirement of old well-established rules (i.e. the ones coming from Commissione Geodetica Italiana) regarding a shared way of structuring entities of numerical cartography, and needs of three-dimensional visualization and analysis of urban and out-of-town landscape.
Definition of a cartographic model - 1
Classe02: Edifici pubbliciGruppo01: Perimetro Sottogruppo01: muro perimetrale esterno_1-5k02: muro perimetrale interno_1-5k03: dividente volumetrica_1k04: portico_1k05: linea di ingombro di scale esterne_1k06: cortili interni_1k07: …..……Gruppo02: CopertureSottogruppo01: linee perimetrali esterne dei tetti_1-5k02: linee perimetrali interne dei tetti_1-5k03: linee di falda dei tetti_1k04: lucernari_1k05: simbolo di inclinazione delle falde_1k06:…..….
Abstract of a first cartographic model derived from those onesof Italian Geodetic Commission and other italian model fornumerical cartography.
The model is hierarchically organized in classes, groups, sub-groups, and cover the most interesting geographical objectswhich are represented in a traditional analogical cartographyat medium and large scale. Classes defined in the model are railways, roads, buildings and artefacts, hydrography, vegetation, orography, administrative boundary.
To each feature class is assigned a code with four couple of numbers.
Besides this model is also organized to support a first simplygeneralization from 1:1000 to 1:5000 scale.
Andrea Scianna DIRAP – University of Palermo – Italy
Definition of a cartographic model - 2
Feature class are grouped and linked into a schema that is splitted in different smaller schemas, depending on the main classes that are described as follows:
• vegetation: parks and gardens, rows of plants, single plants;
• utilities: networks and pipelines for carrying water, gas, electricity, etc.;
• orography: isohypses, spot heights, breaklines, natural shape;
• hydrography: rivers, lakes, sources;
• transportation infrastructures: roads, railways, undergrounds and their accessories (parking and depot areas, pavements, road axes, etc.);
• buildings: edifices and their accessories, set of buildings, other buildings (i.e. pylons, walls, etc.).
Andrea Scianna DIRAP – University of Palermo – Italy
Definition of a cartographic model - 3Main features of this model are:• structure according to indication of rules coming from OGC and ISO 19100
series;• topological constraints defined together with the geometry;• features structured using 0, 1, 2, 3 dimensional primitives, with the constraint
that each higher primitive derives from the lower; • aggregate objects not defined;• edges composed by straight lines and planar faces;• orientation of faces stored explicitily, using the rule of the right hand;• terrain modelled using contour lines and spot elevations.
Topological schema of the modelModel derived from Kolbe and Groeger
Andrea Scianna DIRAP – University of Palermo – Italy
Definition of a cartographic model - 4
UML Diagram of the “Construction” class
Andrea Scianna DIRAP – University of Palermo – Italy
Definition of a cartographic model - 5
maximum_size
(3D face)
Crowning
(3D ring)roof
(3D oriented face)
wall
(3D oriented face)
ground_size
(3D face)
terrain-building_intersection
(3D ring)Representation of buildings elements
Andrea Scianna DIRAP – University of Palermo – Italy
Definition of a cartographic model – 5-bis
Video-representation of an example model
Andrea Scianna DIRAP – University of Palermo – Italy
Definition of a cartographic model - 6
cycle_path
street axis
parking
terrain-building_intersection
pedestrian
railway_area
Representation of three feature classes (raiways, roads, constructions)
Andrea Scianna DIRAP – University of Palermo – Italy
Software implementation
In order to better reach the aims proposed, particularly regarding structuring cartography in accordance with the model defined, a software has been designed.
The software is implemented like an “ARX” (Autocad Runtime eXtensions) component, in AutoCAD environment.
It has been developed in C++ language, and it uses an mdb file as database to store information.
It can be used on many of recent versions of Autocad (100 % compliant with 2004, 2005, 2006 versions), including Autodesk Map too.
Andrea Scianna DIRAP – University of Palermo – Italy
Software functionalities
After launching the application it is opened a popup window, with a multitabmenu structure essentially allows you:
- to define (“set” button) various components of a feature, like crowning, walls, roof, and so on, giving at the same time semantic attributes too and storing all them into an external database;
- to get information (“get” button) on single entities and on entities belonging to a particular feature, as defined above;
Today development concerns the capabilities to export so structured data in GML3 format, complying with our model, using a suitable application schema.
Subsequently a browser for this type of data will be implemented.
Andrea Scianna DIRAP – University of Palermo – Italy
Software demo
Andrea Scianna DIRAP – University of Palermo – Italy
Conclusions
The model will evolve when it will be used, but there are some important step in order to give life actually to the model. Some of them are:
• Browser implementation for 2D and 3D visualization in order to test the model for visual applications;
• Study the method to store objects’ updating;
• Studying methods to transfer 3D GML data in existing spatial database formats
• Exploring all the ways to query the model
Andrea Scianna DIRAP – University of Palermo – Italy
University of Palermo CNR (National Research Council)
Italy
Thanks for your attention !
http://gislab.dirap.unipa.it