Frequently asked questions

Last updated according to PyWPS 3.0.x branch.

Which version of PyWPS should I use?

Always, you should use the latest stable version. Older versions (1.0.0, 2.0.x) are really outdated and you should better not use them.

How to debug PyWPS processes?

You have several possibilities:

• Run PyWPS from command line directly from command line:

  $ ./wps.py "&service=wps&version=0.4.0&request=execute&datainputs=input1,value1,input2,value2,..."

• See error log file from your web server. I use program tail:

  $ tail -f /var/log/apache/error.log |sed -e "s/\[.*\] //g"
  PyWPS GCmd: r.rescale out=kat_dop_k_2004_1188372842 in=dop_k_2004_1188372842\
              to=0,255 to kat_dop_k_2004_1188372842[0,255]
  PyWPS GCmd: r.support map=dop_k_2004_1188372842 title="drasil2"
  PyWPS GCmd: r.support map=kat_dop_k_2004_1188372842 title="drasil2"
  PyWPS ERROR: Could not perform command:
          r.support map=kat_dop_k_2004_1188372842 title="drasil2"
          in process K2O, method execute() /home/bnhelp/pfwps/wps.py:
              79: DeprecationWarning:
                  Non-ASCII character '\xc2' in file
                  /usr/home/bnhelp/pfwps/pywps/processes/pf_interpolate_grass.py
                  on line 51, but no encoding declared;
          see http://www.python.org/peps/pep-0263.html for details
  from pywps.processes import *
  PyWPS GCmd: g.region rast=mask2004@medlov res=5 1>&2

• See the logfile, which you have set in the configuration file, in the [server] section

How to run command line commands?

Use build-in cmd() method of the process:

self.cmd(["ogr2ogr","output","input"])

How to run GRASS commands?

The same way, like normal commands:

self.cmd(["g.region","rast=raster"])

Where can I find documentation to process writing in general?

Of course, there is Documentation, but it does not contain modules documentation yet. To get this, try:

pydoc pywps/Process/Process.py
pydoc pywps/Process/InputsAndOutputs.py

Have a look at doc/examples/processes directory

How to cite PyWPS software?

• PyWPS Development Team, 2009. Python Web Processing Service (PyWPS)

  Software, Version XXXX. http://pywps.wald.intevation.org

• Cepicky, J. (2007): PyWPS 2.0.0: The presence and the future.

  Proceedings Geoinformatics FCE CTU 2007,Prague, Czech Republic, 19th Sept. 2007, Electronic document PDF: http://geoinformatics.fsv.cvut.cz/gwiki/PyWPS_2.0.0:_The_presence_and_the_future

• Cepicky, J., and Becchi, L., 2007, Geospatial Processing via

  Internet on Remote Servers – PyWPS. OSGeo Journal, 1, 39-42. http://www.osgeo.org/journal