WPS offering spatial data fusion processes to the COBWEB framework

fusion branch for 52n WPS

Description (from https://github.com/52North/WPS)

The 52°North Web Processing Service (WPS) enables the deployment of geo-processes on the web in a standardized way. It features a pluggable architecture for processes and data encodings. The implementation is based on the current OpenGIS specification: 05-007r7.

Its focus was the creation of an extensible framework to provide algorithms for generalization on the Web. More information available at the 52°North Geoprocessing Community.

Structure

The following module is added to the WPS framework:

• /52n-wps-fusion - contains wrapper functions for the JAVA spatial data fusion library (https://github.com/GeoinformationSystems/SpatialDataFusion)

Installation

The project is built using Maven install. The spatial data for unit tests is not uploaded. To prevent build failures, those tests need to be ignored.

The dependencies for the group de.tudresden.gis can be obtained from https://github.com/GeoinformationSystems/SpatialDataFusion.

For running the service, the compiled project (WAR-file) must be deployed using a servlet container (e.g. Tomcat). The service functionality can be accessed using the OGC WPS standard (http://www.opengeospatial.org/standards/wps).

Example

The following request is used to calculate distance relations between input features. It requires 3 inputs: (1) the reference dataset (IN_SOURCE), (2) the target dataset (IN_TARGET) and (3) a distance threshold (IN_THRESHOLD). The result is a set of feature relations (OUT_RELATIONS) that contains distance measurements for each pair of features within the threshold distance. It supports two types of relations: the distance relation and the intersect relation. The former assings the distance between features, whereas the latter indicates that two input features overlap.

<wps:Execute service="WPS" version="1.0.0"
xmlns:wps="http://www.opengis.net/wps/1.0.0"
xmlns:ows="http://www.opengis.net/ows/1.1"
xmlns:ogc="http://www.opengis.net/ogc"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.opengis.net/wps/1.0.0
http://schemas.opengis.net/wps/1.0.0/wpsExecute_request.xsd">
<ows:Identifier>de.tudresden.gis.fusion.algorithm.GeometryDistance</ows:Identifier>
   <wps:DataInputs>
     <wps:Input>
       <ows:Identifier>IN_SOURCE</ows:Identifier>
       <wps:Reference
schema="http://schemas.opengis.net/gml/3.1.1/base/feature.xsd"
xlink:href="http://cobweb.gis.geo.tu-dresden.de/wfs?service=wfs&amp;version=1.1.0&amp;request=GetFeature&amp;typename=sampleObs&amp;maxfeatures=1000"
method="GET"/>
     </wps:Input>
     <wps:Input>
       <ows:Identifier>IN_TARGET</ows:Identifier>
       <wps:Reference
schema="http://schemas.opengis.net/gml/3.1.1/base/feature.xsd"
xlink:href="http://cobweb.gis.geo.tu-dresden.de/wfs?service=wfs&amp;version=1.1.0&amp;request=GetFeature&amp;typename=sampleObs&amp;maxfeatures=1000"
method="GET"/>
     </wps:Input>
     <wps:Input>
       <ows:Identifier>IN_THRESHOLD</ows:Identifier>
       <wps:Data>
         <wps:LiteralData dataType="xs:double">0.005</wps:LiteralData>
       </wps:Data>
     </wps:Input>
   </wps:DataInputs>
   <wps:ResponseForm>
   <wps:RawDataOutput mimeType="text/turtle">
       <ows:Identifier>OUT_RELATIONS</ows:Identifier>
     </wps:RawDataOutput>
   </wps:ResponseForm>
</wps:Execute>

The result of the example is provided to the client using the RDF Turtle serialization. The structure is as follows:

_:FeatureRelation_0bc5341d-5cae-4f6e-98c2-ed1f7613b3b1
	a fusion:featureRelation ;
	relation:target <...#sampleObs.48> ;
	relation:source <...#sampleObs.24> ;
	fusion:relationMeasurement [
		a fusion:relationMeasurement ;
		relation:target fusion:geometryProperty ;
		rdf:value "0.0024680243110686883"^^xsd:decimal ;
		relation:source fusion:geometryProperty ;
		dc:description <http://tu-dresden.de/uw/geo/gis/fusion/operation/spatial#distance> ;
	] .