terrestris / inverted-polygon-wps

WPS process to calculate a specific geometric difference

Get an inverted polygon

A WPS for GeoServer that can be used to obtain a polygon with holes. It roughly works as follows:

• input is a GeoJSON feature collection (named inputFeatures)
• a polygon spanning the whole world in EPSG:3857 is created
• one by one the input geometries are subtracted from the polygon using the JTS difference operation

The resulting geometry will then be output as a GeoJSON geometry and be provided as the result output parameter.

Download

Download the latest version from here.

Installation

Simply copy the WPS into the WEB-INF/lib directory where GeoServer is deployed.

cURL example:

curl -X POST -F 'file=@req.xml' 'http://localhost:8080/geoserver/ows'

Contents of req.xml:

<wps:Execute version="1.0.0" service="WPS" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.opengis.net/wps/1.0.0" xmlns:wfs="http://www.opengis.net/wfs" xmlns:wps="http://www.opengis.net/wps/1.0.0" xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:gml="http://www.opengis.net/gml" xmlns:ogc="http://www.opengis.net/ogc" xmlns:wcs="http://www.opengis.net/wcs/1.1.1" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.opengis.net/wps/1.0.0 http://schemas.opengis.net/wps/1.0.0/wpsAll.xsd">
  <ows:Identifier>gs:InvertedPolygon</ows:Identifier>
  <wps:DataInputs>
    <wps:Input>
      <ows:Identifier>inputFeatures</ows:Identifier>
      <wps:Data>
        <wps:LiteralData>{
            "type": "FeatureCollection",
            "features": [
                {
                    "type": "Feature",
                    "geometry": {
                        "type": "Polygon",
                        "coordinates": [
                            [
                                [
                                    0.0,
                                    0.0
                                ],
                                [
                                    10.0,
                                    0.0
                                ],
                                [
                                    10.0,
                                    10.0
                                ],
                                [
                                    0.0,
                                    10.0
                                ],
                                [
                                    0.0,
                                    0.0
                                ]
                            ]
                        ]
                    },
                    "properties": {
                        "prop0": "value0",
                        "prop1": 7
                    }
                }
            ]
        }</wps:LiteralData>
      </wps:Data>
    </wps:Input>
  </wps:DataInputs>
  <wps:ResponseForm>
    <wps:RawDataOutput mimeType="application/octet-stream">
      <ows:Identifier>result</ows:Identifier>
    </wps:RawDataOutput>
  </wps:ResponseForm>
</wps:Execute>