Transcript Document 7852049

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
Main Topics
• Introduction
• GeoFrame-A Framework
• GISCASE’S Architecture
• Implementation
• Conclusions and Future Work
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-A Framework
PGeoFrame-A
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).
NonGeographic
1...*
Object
<<instantiate>>
0...1
Metadata
parameter
Process
Geometadata
0...1
<<instantiate>>
parameter
Geographic 1...*
Phenomenon
Geographic
Object
represents
*
Spatial
Object
Geographic
Field
represents
*
Field
Representation
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 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.
GISCASE’s Architecture
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.
GPtoXML Parser
GISCASE’s Architecture
XMI File
<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>
XML-Schema
Elements from the
XMI file are coded
into a new XML
file, based on a
XML-Schema
(the XML encode
for GeoFrame-A).
<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>
Generated XML File
<Spatial ObjectNodeId="GisCase_AC2">
<Name>GisCase_DS_1</Name>
<Representation>polygon</Representation>
<TableName>GisCase_DS_1</TableName>
</Spatial>
GISCASE’s Architecture
GPtoXML Parser
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
BF
BF
BF
BF
CodPar
Line
Point
Polygon
Constant
NumPar
1
1
1
2
CodOp
BF
BF
BF
RefIn
Line
Point
Polygon
RefOut
Polygon
Polygon
Polygon
GISCASE’s Architecture
XMLtoGIS Generator
Generates source code from the XML specification.
GISCASE’s Architecture
XMLtoGIS Generator
For each GIS software an API is needed in order to map
GeoFrame-A operations onto the logical model of the GIS
software.
Mapping the buffer operation to TerraLib
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.
Implementation
As a free software project sponsored by CNPq, all the
external components adopted are free software.
Component
Requisites
Adopted
Graphical
Editor
must implement an actitivy
diagram and generate a XMLlike output
Gentleware's Poseidon
(Community Edition)
GIS API
must manage a GDB and
functions of geographic
analysis
TerraLib from INPE
Interface
platform with interface
components
Eclipse Platform
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
Workflow to perform a geographic analysis process with
GISCASE:
• 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)
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