[GRASS-dev] GRASS GIS 7 and QGIS connected using the Web Processing Service (WPS)

Fri Apr 15 04:59:46 EDT 2011

Hello Moritz,
the problem is the temporal GML file generation in qgswpstools.py.
This piece python code should solve the problem, which is also
included in the patch:

qgswpstools.py at line ~230

    # Check in case a ".g" was attached to the tempfile
    if os.path.isfile(tmpFile + ".g") == True:
      tmpFile = tmpFile + ".g"

This error should only occur with vector data. Raster data should work.

Best regards
Soeren

2011/4/15 Moritz Lennert <mlennert at club.worldonline.be>:
> Hi Soeren,
> [cc to Horst Düster - I'm not subscribed to the QGIS lists, trying to limit
> my flow of mails, but we can take it over there if you prefer, but I want to
> make sure that this is really a plugin problem and not my bad usage of your
> wps-grass bridge]
>
> On 15/04/11 09:40, Moritz Lennert wrote:
>>
>> On 15/04/11 09:20, Soeren Gebbert wrote:
>>>
>>> Hi Moritz,
>>> the problem may be related to the QGIS WPS plugin version. The plugin
>>> is still in an experimental state and under active development, but
>>> the latest SVN version should be usable. Which version of the plugin
>>> do you use?
>>
>> 0.5.
>
> 0.5.0 to be precice.
>
> I've found the DEBUG option in the source code. Now I can see the request
> XML and the problem seems to be this (trying to launch a simple v.perturb on
> the busstopsall map of the shapefile collection of the nc_spm grass demo
> data):
>
> <ows:Identifier>input</ows:Identifier>
> <ows:Title>input</ows:Title>
> <wps:Data>
> <wps:ComplexData mimeType="text/xml"
> schema="http://schemas.opengis.net/gml/2.1.2/feature.xsd"
> enconding="utf-8"></wps:ComplexData>
> </wps:Data>
> </wps:Input>
>
> i.e. the input data info is empty.
>
> The same seems to be true for the output data:
>
> <ows:Identifier>input</ows:Identifier>
> <ows:Title>input</ows:Title>
> <wps:Data>
> <wps:ComplexData mimeType="text/xml"
> schema="http://schemas.opengis.net/gml/2.1.2/feature.xsd"
> enconding="utf-8"></wps:ComplexData>
> </wps:Data>
> </wps:Input>
>
> Whereas the 'parameter' option contains the value I gave:
>
> <wps:Input>
> <ows:Identifier>parameters</ows:Identifier>
> <ows:Title>parameters</ows:Title>
> <wps:Data>
> <wps:LiteralData>20</wps:LiteralData>
> </wps:Data>
> </wps:Input>
>
>
> Here some info about my config:
>
> pywps.cfg:
>
> [grass]
> path=/home/mlennert/SRC/GRASS/grass_trunk/dist.i686-pc-linux-gnu/bin:/home/mlennert/SRC/GRASS/grass_trunk/dist.i686-pc-linux-gnu/scripts
> addonPath=
> version=7.0svn
> gui=text
> gisbase=/home/mlennert/SRC/GRASS/grass_trunk/dist.i686-pc-linux-gnu
> ldLibraryPath=/home/mlennert/SRC/GRASS/grass_trunk/dist.i686-pc-linux-gnu/lib
> gisdbase=/home/mlennert/WWW/pywps/grassdata
>
> pywps.cgi:
>
> export PYWPS_CFG="/home/mlennert/WWW/pywps/pywps.cfg"
> export PYWPS_PROCESSES="/home/mlennert/SRC/WPS_PROCESS"
>
> and in WPS_PROCESSES I have all the files from your original
> wps-grass-bridge svn directory:
>
> GlobalGrassSettings.py
> GlobalGrassSettings.pyc
> GrassXMLtoPyWPS.py
> GrassXMLtoYAML.py
> GrassXMLtoZCFG.py
> PyWPSGrassModuleStarter.py
>
> the gms and wpsXML directories (I erased the zoo-related) and a long list of
> grass modules descriptors, of which just the v.perturb one as example:
>
> # ################################################ #
> # This process was generated using GrassXMLtoPyWPS #
> # Author: Soeren Gebbert                           #
> # Mail: soerengebbert <at> googlemail <dot> com    #
> # ################################################ #
>
> from pywps.Process import WPSProcess
>
> from PyWPSGrassModuleStarter import PyWPSGrassModuleStarter
>
> class v_perturb(WPSProcess):
>
>  def __init__(self):
>    WPSProcess.__init__(self, identifier = 'v.perturb', title = 'Random
> location perturbations of vector points.', version = 1, statusSupported =
> True, storeSupported = True, metadata = [{'type': 'simple', 'title':
> 'vector'}, {'type': 'simple', 'title': 'statistics'}], abstract =
> 'http://grass.osgeo.org/grass70/manuals/html70_user/v.perturb.html')
>
>    # Literal and complex inputs
>    self.addComplexInput(identifier = 'input', title = 'Data source for
> direct OGR access', minOccurs = 1, maxOccurs = 1, formats = [{'mimeType':
> 'text/xml', 'schema': 'http://schemas.opengis.net/gml/2.1.2/feature.xsd',
> 'encoding': 'UTF-8'}, {'mimeType': 'text/xml', 'schema':
> 'http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd', 'encoding': 'UTF-8'},
> {'mimeType': 'application/dgn', 'schema': 'None', 'encoding': 'None'},
> {'mimeType': 'application/shp', 'schema': 'None', 'encoding': 'None'},
> {'mimeType': 'application/x-zipped-shp', 'schema': 'None', 'encoding':
> 'None'}])
>    self.addLiteralInput(identifier = 'layer', title = 'A single vector map
> can be connected to multiple database tables. This number determines which
> table to use. Layer name for direct OGR access.', minOccurs = 1, maxOccurs =
> 1, type = type("string"), default = "-1")
>    self.addLiteralInput(identifier = 'distribution', title = 'Distribution
> of perturbation', minOccurs = 0, maxOccurs = 1, type = type("string"),
> default = "uniform", allowedValues = ['uniform', 'normal'])
>    self.addLiteralInput(identifier = 'parameters', title = 'If the
> distribution is uniform, only one parameter, the maximum, is needed. For a
> normal distribution, two parameters, the mean and standard deviation, are
> required.', minOccurs = 1, maxOccurs = 1024, type = type(0.0), allowedValues
> = '*')
>    self.addLiteralInput(identifier = 'minimum', title = 'Minimum deviation
> in map units', minOccurs = 0, maxOccurs = 1, type = type(0.0), default =
> 0.0)
>    self.addLiteralInput(identifier = 'seed', title = 'Seed for random number
> generation', minOccurs = 0, maxOccurs = 1, type = type(0), default = 0)
>
>    # complex outputs
>    self.addComplexOutput(identifier = 'output', title = 'Name for output
> vector map', formats = [{'mimeType': 'text/xml', 'schema':
> 'http://schemas.opengis.net/gml/2.1.2/feature.xsd', 'encoding': 'UTF-8'},
> {'mimeType': 'text/xml', 'schema':
> 'http://schemas.opengis.net/kml/2.2.0/ogckml22.xsd', 'encoding': 'UTF-8'}])
>
>  def execute(self):
>    starter = PyWPSGrassModuleStarter()
>    starter.fromPyWPS("v.perturb", self.inputs, self.outputs, self.pywps)
>
> if __name__ == "__main__":
>  process = v_perturb()
>  process.execute()
>
> Any ideas ?
>
> Moritz
>
>
>>> 2011/4/14 Moritz Lennert<mlennert at club.worldonline.be>:
>>>>
>>>> Soeren,
>>>>
>>>> Thanks for the great work on WPS integration !
>>>>
>>>> On 28/01/11 11:44, Soeren Gebbert wrote:
>>>>>
>>>>> How to attach GRASS modules to PyWPS using the wps-grass-bridge is
>>>>> documented here:
>>>>> http://code.google.com/p/wps-grass-bridge/wiki/PyWPS_Integration
>>>>>
>>>>> Well, the code isn't stable yet but it demonstrates the possibilities
>>>>> of this approach.
>>>>
>>>> I've tried following the above instructions, and the server does give a
>>>> correct answer for GetCapabilities. I can also see the list of
>>>> modules in
>>>> the QGIS WPS plugin and get the GUI of a module. However, once I run the
>>>> module I always get the following error, whatever the module I try:
>>>>
>>>> <wps:ProcessFailed>
>>>> <wps:ExceptionReport>
>>>> <ows:Exception exceptionCode="NoApplicableCode">
>>>> <ows:ExceptionText>argument 1 must be string or buffer,
>>>> not None</ows:ExceptionText>
>>>> </ows:Exception>
>>>> </wps:ExceptionReport>
>>>> </wps:ProcessFailed>
>>>>
>>>>
>>>> Any idea what could be wrong ? I can't find a way to see what URL the
>>>> QGIS
>>>> plugin sends to the server.
>>>>
>>>> Moritz
>>>>
>>>>
>>
>>
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>
>