WPS

GRASS based OGC Web Processing Service (WPS) standard implementations

Inside GRASS 7

In GRASS7, the WPS process description can be automatically generated with the option '--wps-process-description'. See announcement.

Example:

r.grow --wps-process-description


<?xml version="1.0" encoding="UTF-8"?>
<wps:ProcessDescriptions xmlns:wps="http://www.opengis.net/wps/1.0.0"
xmlns:ows="http://www.opengis.net/ows/1.1"
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/wpsDescribeProcess_response.xsd"
 service="WPS" version="1.0.0" xml:lang="en-US"> 
	<ProcessDescription wps:processVersion="1" storeSupported="true" statusSupported="true">
		<ows:Identifier>r.grow</ows:Identifier>
		<ows:Title>Generates a raster map layer with contiguous areas grown by one cell.</ows:Title>
		<ows:Abstract>Generates a raster map layer with contiguous areas grown by one cell.</ows:Abstract>
		<ows:Metadata xlink:title="raster" />
		<DataInputs>
			<Input minOccurs="1" maxOccurs="1">
				<ows:Identifier>input</ows:Identifier>
				<ows:Title>Name of input raster map</ows:Title>
				<ows:Abstract>Name of input raster map</ows:Abstract>
				<ComplexData maximumMegabytes="2048">
					<Default>
						<Format>
							<MimeType>image/tiff</MimeType>
						</Format>
					</Default>
					<Supported>
						<Format>
							<MimeType>image/tiff</MimeType>
						</Format>
						<Format>
							<MimeType>image/png</MimeType>
						</Format>
						<Format>
							<MimeType>application/grass-raster-ascii</MimeType>
						</Format>
						<Format>
							<MimeType>application/grass-raster-binary</MimeType>
						</Format>
					</Supported>
				</ComplexData>
			</Input>
			<Input minOccurs="0" maxOccurs="1">
				<ows:Identifier>radius</ows:Identifier>
				<ows:Title>Radius of buffer in raster cells</ows:Title>
				<ows:Abstract>Radius of buffer in raster cells</ows:Abstract>
				<LiteralData>
					<ows:DataType ows:reference="xs:float">float</ows:DataType>
					<ows:AnyValue/>
					<DefaultValue>1.01</DefaultValue>
				</LiteralData>
			</Input>
			<Input minOccurs="0" maxOccurs="1">
				<ows:Identifier>metric</ows:Identifier>
				<ows:Title>Metric</ows:Title>
				<ows:Abstract>Metric</ows:Abstract>
				<LiteralData>
					<ows:DataType ows:reference="xs:string">string</ows:DataType>
					<ows:AllowedValues>
						<ows:Value>euclidean</ows:Value>
						<ows:Value>maximum</ows:Value>
						<ows:Value>manhattan</ows:Value>
					</ows:AllowedValues>
					<DefaultValue>euclidean</DefaultValue>
				</LiteralData>
			</Input>
			<Input minOccurs="0" maxOccurs="1">
				<ows:Identifier>old</ows:Identifier>
				<ows:Title>Value to write for input cells which are non-NULL (-1 => NULL)</ows:Title>
				<ows:Abstract>Value to write for input cells which are non-NULL (-1 => NULL)</ows:Abstract>
				<LiteralData>
					<ows:DataType ows:reference="xs:integer">integer</ows:DataType>
					<ows:AnyValue/>
				</LiteralData>
			</Input>
			<Input minOccurs="0" maxOccurs="1">
				<ows:Identifier>new</ows:Identifier>
				<ows:Title>Value to write for "grown" cells</ows:Title>
				<ows:Abstract>Value to write for "grown" cells</ows:Abstract>
				<LiteralData>
					<ows:DataType ows:reference="xs:integer">integer</ows:DataType>
					<ows:AnyValue/>
				</LiteralData>
			</Input>
			<Input minOccurs="0" maxOccurs="1">
				<ows:Identifier>-m</ows:Identifier>
				<ows:Title>radius is in map units rather than cells</ows:Title>
				<ows:Abstract>radius is in map units rather than cells</ows:Abstract>
				<LiteralData>
					<ows:DataType ows:reference="xs:boolean">boolean</ows:DataType>
					<ows:AllowedValues>
						<ows:Value>true</ows:Value>
						<ows:Value>false</ows:Value>
					</ows:AllowedValues>
					<DefaultValue>false</DefaultValue>
				</LiteralData>
			</Input>
		</DataInputs>
		<ProcessOutputs>
			<Output>
				<ows:Identifier>output</ows:Identifier>
				<ows:Title>Name for output raster map</ows:Title>
				<ows:Abstract>Name for output raster map</ows:Abstract>
				<ComplexOutput>
					<Default>
						<Format>
							<MimeType>image/tiff</MimeType>
						</Format>
					</Default>
					<Supported>
						<Format>
							<MimeType>image/tiff</MimeType>
						</Format>
						<Format>
							<MimeType>image/png</MimeType>
						</Format>
						<Format>
							<MimeType>application/grass-raster-ascii</MimeType>
						</Format>
						<Format>
							<MimeType>application/grass-raster-binary</MimeType>
						</Format>
					</Supported>
				</ComplexOutput>
			</Output>
		</ProcessOutputs>
	</ProcessDescription>
</wps:ProcessDescriptions>

Linking to other software

There are currently several WPS implementations which use GRASS as GIS backbone:

• PyWPS: http://pywps.wald.intevation.org/
  • Gallery (live examples)
• WPS by 52n: http://52north.org/maven/project-sites/wps/52n-wps-site/
• ZOO project - Open OSW Platform: http://www.zoo-project.org/
• vtk-grass-bridge: http://code.google.com/p/vtk-grass-bridge/