pywms.py

Dummiest possible implementation of a WMS server.

Allows you to serve a single image using the WMS protocol. It supports only 2 commands:

• GetCapabilities
• GetMap

Most GetMap parameters are ignored, the only used ones are:

• FORMAT: the format of the returned image
• BBOX: the extracted area
• WIDTH, HEIGHT: dimension of the returned image

Tested with QGIS and OpenLayers.

Example usage:

python pywms.py foo.png EPSG:2154 0,0,100,200

The first parameter is the image to serve and the second one is the bounding-box covered by the image (minx,miny,maxx,maxy).

If you have a big image (say 30.000x15.000 pixels), you can use a pyramidal format (tif for instance) to get faster response time.

Example command line to convert your image:

vips im_vips2tiff --vips-progress myimage.png  myimage.tif:jpeg:75,tile:256x256,pyramid

Notes regarding ImageMagick: pywms uses Wand python binding to ImageMagick. If you try to use it with big images you might hit ImageMagick's default security policy.

You can simply write a custom policy.xml, e.g:

<policymap>
  <policy domain="resource" name="width" value="40KP"/>
  <policy domain="resource" name="height" value="40KP"/>
  <policy domain="resource" name="memory" value="4GB"/>
  <policy domain="resource" name="map" value="4GB"/>
  <policy domain="resource" name="area" value="4GB"/>
  <policy domain="resource" name="disk" value="1GB"/>
</policymap>

and then set MAGICK_CONFIGURE_PATH value to the folder containing your custom policy.xml.