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GI2011-X-border-SDI/GDI-Symposium, 23..5.2011: Bad Schandau (SAX) [ 11. Sächsisches GIS-Forum ] 24.5.2011: Decin (CZE) [ 1. Bohemian#Saxonian GIS-Forum ]
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Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
1
PyWPS
Jachym Cepicky, Karel Charvát
[email protected]://bnhelp.cz
[email protected]://ccss.cz
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
2
PyWPS
● Implementation of OGC Web Processing Service (OGC WPS) on the server-side
● Started 2006● Python-based● Support for GRASS GIS, GDAL, PROJ4, R, ...
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
3
What is PyWPS not
● PyWPS is no analytical tool or engine. It does not perform any type of geospatial calculation.
● PyWPS is not special XML parser or generator. It does not validate your GMLs against given schemas (yet), it does not build GML from Python objects.
● It is not complicated. Or, it should not be.
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
4
Shortly about OGC WPS
● Protocol similar to WMS● GetCapabilities → List of Processes
● DescribeProcesses → Selected proces specification (In- and Outputs)
● Execute → Performs calculation, returns result
● KVP vs XML● service=WPS&request=GetCapabilities&version=1.0.0● <ows:GetCapabilities xmlns:ows="http://www.opengis.net/ows/1.1" xmlns:wps="http://www.opengis.net/wps/1.0.0" … service="WPS">
<ows:AcceptVersions>
<ows:Version>1.0.0</ows:Version>
</ows:AcceptVersions>
</ows:GetCapabilities>
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
5
PyWPS Featuers
● Python-based (< 3.0)● WPS 1.0.0● No processes within the distribution → User has
to code custom ones● On-the-fly creation of GRASS temporary
Location/Mapset, if the process does require GRASS modules
● Support for Java libraries (Sextant, …)● WSDL/SOAP interface
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
6
PyWPS Architecture
Processes
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
7
PyWPS Architecture
● PyWPS is „just“ thin layer (wrapper) between Internet and processing tool
● As processing tool, various popular GIS programs can be used, for example:● GRASS GIS● GDAL/OGR● Proj4● Shapely, R, ...
● The process is to be desgined by the „user“ - programator, who will setup PyWPS
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
8
News from SVN
● Runs with Jython (Java implementation of Python interpreter) → Direct access to Java world (Used in Humboldt project)
● Support for GRASS 7 WPS interface (Sören Gebert)
● WSDL/Soap bindings (Jorge de Jesus) → PyWPS 3.2
● Orchestrization of processes using Taverna
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
9
PyWPS 4.0 ideas
● Be Python 3 ready - use Python 2.7 (currently, it should work on Python 2.4+)
● Use lxml for XML parsing AND writing
● Bring assynchronous calls to windows
● In the debug mode, validate input XMLs against schemas.
● Prepare for WPS 2.0
● More closer integration with GRASS GIS
● License change
● Process concept● Use XML conofiguration?
● Jython issue (lxml is CPython-based)
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
10
Links
● Main page http://pywps.wald.intevation.org● Wiki http://wiki.rsg.pml.ac.uk/pywps/● http://opengeospatial.org/standards/wps
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
11
Supportes
● Help Service – Remote Sensing s.r.o. http://bnhelp.cz
● Netmar project http://netmar.nersc.no/● Prezem project http://prezem.cz● Humboldt project http://esdi-humboldt.eu
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
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Examples in the real worldhttp://geo.sazp.sk
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
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Examples in the real worldhttp://povoden.kraj-lbc.cz
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
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Examples in the real worldhttp://dev.bnhelp.cz/inspire/client
Jachym [email protected] Service – Remote Sensing
PyWPS
GI2011-X-border-SDI/GDI Symposium
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Projects using PyWPS
● Prezem (precision farming) http://prezem.cz● Humboldt http://esdi-humboldt.eu● Netmar http://netmar.nersc.no/● …● PyWPS is used for various INSPIRE-related
tasks (e.g. Transformation service) among others at JRC Ispra.
