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Geospatial data integration and visualisation using open standard Gilles TALADOIRE. University of New Caledonia (UNC) TIARE Computer Science Laboratory New Caledonia a project with IRD The French scientific research institute for development LATICAL Remote Sensing Laboratory New Caledonia. - PowerPoint PPT Presentation
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Geospatial data integration and visualisation using open standard
Gilles TALADOIRE
University of New Caledonia (UNC)TIARE Computer Science LaboratoryNew Caledonia
a project with IRDThe French scientific research institutefor developmentLATICAL Remote Sensing LaboratoryNew Caledonia
Where is New Caledonia ?
Environmental Information System
Data AcquisitionRemote SensingGround Sensor
Data Archiving :Conception
StorageExtraction
User InterfaceData Processing and Analysis
System integration : From acquisition to visualisation
satellite sensor, aerial sensor, ground sensor==> heterogeneous data (textual, numerical, vector, images, …)==> heterogeneous formats
conceptual modelling, storage and extraction==> heterogeneous systems (GIS, DBMS, …)==> heterogeneous formats
Connected systems : expert systems, neural networks,multi-agents systems, data mining systems, imageprocessing and analysis, simulations, scientific model, …==> heterogeneous systems==> heterogeneous formats
Data visualisationadapted to the different users of an environmental projectavailable on Internet, graphically
==> Heterogeneous Data, Formats and Systems
Independent systems (generally)==> incompatibility or incoherence in this process
Many partners involved in environmental projects(expert firm, administration, research institute, …)
==> Not the same methods Not the same software
Not a single place
==> The generalised use of standards
Existing standardisation initiatives
In the domain of geospatial information : the Technical Comity ISO 211 :
the standardisation in the field of digital geographic information the OpenGIS consortium
the definition of specification to define transparent access toheterogeneous geodata and geoprocessing resourcesin a networked environmentGeographic Markup Language (GML)
In the domain of the internet : World Wide Web Consortium (W3C) Extensible Markup Language (XML)
(the universal format for structured documents and data on the Web) Scalable Vector Graphics (SVG)
(An application of XML for describing two-dimensional graphics)
Architecture for system integration
Data Acquisition :
Remote SensingGround Sensor
Data Archiving :Conception
StorageExtraction
User InterfaceData Processing and Analysis
System integration : From acquisition to visualisation
GML SVGGMLGML
==> The use of GML as common data interface
==> The use of SVG as visualisation solution
Creation of Import/Export module
GIS /Data Base
DataMining Simulation
DataProcessing
ImageProcessing
LearningSystem
ScientificModel
…
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Visualisation : from GML to SVG
Geographic DataDescription Language
Vector GraphicsDescription Language
Transformation to dofor map display
XML Schema
W3C
GML
OG
C
SVG
W3C
XML
W3C
Correspondence between objects
Geometric objet Correspondence
GML SVG<Point> To be determined : rectangle, circle, icon at the point<LineString> <polyline><Box> <rect><LinearRing> Used with <svg:polygon><Polygon> <polygon><MultiPoint> To be determined : rectangle, circle, icon at the point<MultiLineString> A group <g> of <svg:polyline><MultiPolygon> A group <g> of <svg:polygon>’
Feature Correspondence
GML SVGGML Feature
<Xxx><gml:name>feature_name</gml:name>…</Xxx>
SVG group
<g class="Xxx" id="name">…</g>
Geometric property :a point in the example
<Xxx>…<gml:location> <gml:Point> <gml:Coord> <gml:x>valuex</gml:x> <gml:y>valuey</gml:y> </gml:Coord> </gml:Point> </gml:location>…</gml:location>
Base element as in the table :a rectangle in the example
<rect x="valuex" y="valuey" heigth="10" width="10" class="Xxxlocation"/>
Non-geometric property :text, integer, decimal
<gml:name>feature_name</gml:name>
Text as legend
<text x="valuex" y="valuey"class="Xxxname">feature_name</text>
The use of the 'class' property of graphical objects to identify the element originThe properties of one feature are grouped with the <g> elementThe features collections are to group with the <g> elementThe non-geometric properties could be visualised as text on the map like a legend of the object
Example : A water tank has a name and a Point location
GML SVG<WaterTank> <gml:name>Drueulu1</gml:name> <gml:location> <gml:Point> <gml:Coord> <gml:x>512.0</gml:x> <gml:y>362.0</gml:y> </gml:Coord> </gml:Point> </gml:location></WaterTank>
<g class="WaterTank" id="Drueulu1"><rect y="357" x="507" height="10" width="10" class="WaterTanklocation"/><text y="362.0" x="512.0"class="WaterTankname">Drueulu1</text></g>
Display style
No style in GML 2.0
In SVG, three common usage for styling : directly in the SVG content SVG content generated as the output from XSLT transformation SVG content styled with CSS
==> Styling with CSS style sheet using the class names given to SVGelements :
flexible to change the map presentationeasy to do
Example
style sheet "watertank.css"
<g class="WaterTank" id="Drueulu1"><rect y="357" x="507" height="10" width="10" class="WaterTanklocation"/><text y="362.0" x="512.0" class="WaterTankname">Drueulu1</text></g>
.WaterTank {display:inline}
.WaterTanklocation {fill:red;stroke:blue;stroke-width:2; visibility:visible}
.WaterTankname {fill:black; visibility:visible}
part of SVG file SVG rendering
Fusion
GML Document
Style Sheet
SVG DocumentGenerator
The generic SVG generator :- a transformation XSL : XSLT designed speciallyor- a program that parse the XML file : for special processing
XLST transformations generic at two levels :- the application uses only geometric properties defined in the GML features schema, a general XSLT style sheet can be defined and used for all applications of this kind.- the GML application schema use specific geometric properties, the defined XSLT style sheet can be only use with the applications using this schema.
Extensions
Functionality to add in a generic way : The interactivity to manage layers, for zoom and moving functions The automatic generation of legends The use of links and associations of GML
- to visualise the links between the features to show dependencies Example : a water tank supply water to a village, a line is drawn from the tank to the village.
- to establish hyperlink between graphical elements The GML schema parsing :
- to develop a style sheet editor which propose features and properties of the schema- to realise a automatic style sheet generator from the schema
The management of temporal series to animate objects on the map
Conclusion
First stepSpatial data visualisation with a correspondence
between descriptive data and graphical data
Global projectto integrate systems with general use of GML as standard format
Thanks to :
I3S laboratory (University of Nice-Sophia Antipolis - CNRS)to invited me from september 2000 to june 2001