designing and performing geographic analysis processes with giscase cirano iochpe, guillermo n....
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Designing and Performing Geographic Analysis Processes with GISCASE
Cirano Iochpe, Guillermo N. Hess, Cláudio Ruschel, Alécio P. D. Binotto, Luciana V. da Rocha
UFRGS – Instituto de Informática
{ ciochpe, hess, claudior, abinotto, vargas }@inf.ufrgs.br
• Introduction
• GeoFrame-A Framework
• GISCASE’S Architecture
• Implementation
• Conclusions and Future Work
Main Topics
Introduction
Each GIS tool supports its own logical model for both data and process design.
A need:
Models and tools that help the definition / design of geographic data and analysis processes.
Tools used in GDB design could be candidates (ex: MADS, GeoOOA, GeoFrame), if they also supported process definition.
GeoFrame-A: an extension to the GeoFrame Framework that aims to support the design of geographic analysis processes.
Our proposal:
GISCASE: software tool that implements GeoFrame-A concepts. It generates programs that can perform geographic analysis processes.
The GeoFrame Framework:
GeoFrame is an object oriented conceptual framework on the basis of the Unified Modeling Language (UML) (Lisboa, 2000).
It supports geographic database design by providing a set of classes that can be instatiated as well as specialized, and extended.
GeoFrame-A:
Extension that supports the design of geographic analysis processes (Ruschel, 2003).
Metadata
Process
PhenomenonGeographic
Geometadata
ObjectGeographic
FieldGeographic
ObjectSpatial
<<instantiate>>
<<instantiate>>
represents represents
FieldRepresentation
* *
0...1
parameter
parameter
1...*
0...11...*
PGeoFrame-A
NonGeographicObject
The GeoFrame-A Framework
GeoFrame-A uses UML 2 diagrams to specify processes:
-Class Diagram: external specification
Each geographic process type is represented as an Activity Class.
The GeoFrame-A Framework
-Activity Diagram: internal specification
Data represented as object nodes;
Operations modeled as activity nodes;
Both data and control flow possible.
A set of basic geoprocessing operations {DS (Dissolve) ; OV (Overlay) ; SS (Spatial Selection) ; BF (Buffer) ...}
The GeoFrame-A Framework
The GISCASE Tool
GISCASE is a free software developed at UFRGS that generates source code in a programming language which, when compiled and executed, performs geographic analysis processes.
The specification uses UML activity diagrams including GeoFrame-A concepts.
Spatial classes are represented through spatial tables in a GDB.
Operations must be implemented on a GIS software API.
First implementation relies upon TerraLib.
Graphical EditorGPtoXML
Poseidon
GisCaseMain Window
XMI Parser
XMIXML
GPRules
XML Parses(Syntactic and
Semantic validation)
XMLtoGISGenerator
XML
Compiler
SQL /C++
XMLschema
GISdata model
GIS API
GISCASE’s Architecture
GisCase Main Window: Manages GISCASE’s workflow.
Elements: navigation panel, text editor, message window
GISCASE’s Architecture
Graphical Editor
Activity diagrams: CASE tool Poseidon UML (Community Edition)
GISCASE’s Architecture
GPtoXML Parser
Reads the XMI file and performs a semantic analysis.
Result: a clean XML file, from which code generation is possible.
GISCASE’s Architecture
Elements from the XMI file are coded into a new XML file, based on a XML-Schema (the XML encode for GeoFrame-A).
GPtoXML Parser
<UML:CallAction xmi.id = 'I20699am10384031526mm7fce' name = '' isSpecification = 'false' isAsynchronous = 'false'> <UML:Action.script> <UML:ActionExpression xmi.id = 'I20699am10384031526mm7f99' language = 'java' body = 'DS_1'/> </UML:Action.script> </UML:CallAction>
<Spatial ObjectNodeId="GisCase_AC2"> <Name>GisCase_DS_1</Name> <Representation>polygon</Representation> <TableName>GisCase_DS_1</TableName></Spatial>
<xs:element name="Action" substitutionGroup="aux2"> <xs:complexType> <xs:sequence> <xs:element ref="Name"/> <xs:element ref="Input" minOccurs="0" maxOccurs="unbounded"/> <xs:element ref="Output" minOccurs="0" maxOccurs="unbounded"/> </xs:sequence> <xs:attribute name="ActionId" type="xs:ID" use="required"/> <xs:attribute name="Persistent" type="xs:integer" use="optional"/> </xs:complexType></xs:element>
XMI File
XML-Schema
Generated XML File
GISCASE’s Architecture
CodOp CodPar NumParBF Line 1BF Point 1BF Polygon 1BF Constant 2
Object nodes serve as either input or output for Action nodes.Each action node can have one or more input nodes but only one output.
Actions are verified within GP Rules database:• Number of inputs for each action;• Data types of the inputs and outputs.
CodOp RefIn RefOutBF Line PolygonBF Point PolygonBF Polygon Polygon
GPtoXML Parser
GISCASE’s Architecture
XMLtoGIS Generator
Generates source code from the XML specification.
GISCASE’s Architecture
For each GIS software an API is needed in order to map GeoFrame-A operations onto the logical model of the GIS software.
XMLtoGIS Generator
bool GcBuffer(string inLayerName, TeGeomRep inRepName, string outLayerName, double dist, TeAdo* db){ TeLayer* inLayer = new TeLayer(inLayerName);
db->loadLayer(inLayer);TeProjection* proj = inLayer->projection ();...TePolygonSet bufferPol;TeLayer* outLayer = new TeLayer(outLayerName, db, inLayer->box(), inLayer->projection());int layerId = outLayer->id();db->Buffer(tableRep, inRepName ,objsIn, bufferPol, dist);outLayer->addPolygons(bufferPol); }
This module generates the source code that accesses the GIS operations through its API, passing respective parameters when needed.
The source code generated must be compiled and linked with the required GIS libraries, or interpreted within the GIS software environment.
Mapping the buffer operation to TerraLib
GISCASE’s Architecture
Implementation
Component Requisites Adopted
Graphical Editor
must implement an actitivy diagram and generate a XML-like output
Gentleware's Poseidon (Community Edition)
GIS API
must manage a GDB and functions of geographic analysis TerraLib from INPE
Interfaceplatform with interface components Eclipse Platform
As a free software project sponsored by CNPq, all the external components adopted are free software.
Interface and parsers built in Java: free software, platform independent, easy to parse XML files
GISCASE’s exclusive Library to access TerraLib API developed in C++
Implementation
The XMLtoGIS module generates a main procedure and appends the source code for the operations used in the process from the library GcGeoOperations for TerraLib.
int main(){ string dbname = "C:\GeoDB\Geoinfo.mdb"; TeAdo* db = new TeAdo(); db->connect("localhost","","",dbname,0)) cout << "Erro em conetar-se via ADO: " << db->errorMessage() << endl; TeAdoPortal* dbPortal = new TeAdoPortal(db); TeDatabasePortal* portal = dbPortal; TeInitQuerierStrategies(); val = GcDissolve("Municipality","GisCase_DS_1","IDADMREGION",db, portal); if (!val)
cout << "Erro na função GcDissolve!" << endl; val = GcOverlay("GisCase_DS_1","River_Basin","Region_by_Basin","AND",db, portal); if (!val)
cout << "Erro na função GcOverlay!" << endl; portal->freeResult(); db->close(); return 0;}
Implementation
GcGeoOperations Library for TerraLib
Source code that maps the main procedure to TerraLib library and TerraView functions.
Operations implemented in the first version:
• GcSelection: selects objects by attributes
• GcRegionSelection: selects objects inside a polygon
• GcSpatialSelection: selects objects through a spatial predicate
• GcBuffer: creates a polygon with a specified distance
• GcOverlay: does the overlay of two sets of spatial objects
• GcDissolve: generalizes the input objects through an attribute
• GcCentroid: finds the centroid of a polygon
• GcAlgebra: updates attributes in one layer (SQL Update)
• GcDistance: mesures the distance of two geometries
• Prepare a GDB, compatible to the GIS API, with the input data
• In the GISCASE tool:
- Design the process in the graphical editor
- Verify semantics and generate source code
• Compile and execute (for TerraLib, with Visual Studio)
• Verify the results in a map viewer (ex: TerraView)
Workflow to perform a geographic analysis process with GISCASE:
Contributions:
• a XML schema able to define a geographic process
• complements a set of applications developed with TerraLib
• a modular and extendable architecture to design geographic process
• a learning tool to programmers
Future work:
• to implement other geographic analysis operations still using TerraLib
• code generation for other GIS platforms
• allow the use of a script language as an alternative to the graphical editor