[mapserver-users] Trying to get GeoWebCache to work with MapServer

[John Westwood]

Hi,

I am having some problems trying to get GeoWebCache working with MapServer. I currently have a fully functional MapServer / TileCache / OpenLayers system setup on the server. MapServer is functioning as a WMS server.

With a GeoWebCache layer I receive pink tiles, right clicking and viewing the image tile reports the following type of GeoWevCache error:

400: Empty metatile, error message: MimeType mismatch, expected image/png but got text/html

I believe this means that GeoWebCache received a text response from MapServer instead of an image response. The previous error also came with a MapServer url. Hitting that url brings back the following MapServer error:

msEvalRegex(): Regular expression error. String (/data/map-files/gbhgis.map?exceptions=application/vnd.ogc.se_inimage) failed expression test

I tried stripping down my map file to just a single layer but that did not help. I also tried using the shp2img command with my full map file:

shp2img -m /data/map-files/gbhgis.map -o test.png -map_debug 3

The following debug information was output and the resulting png was blank / transparent:

msDrawMap(): Drawing Label Cache, 0.000s
msDrawMap() total time: 0.001s
msSaveImage() total time: 0.031s

There are many layers in my map file, yet nothing much happened with shp2img. Something seems a bit fishy. But everything works alright with Tilecache or with MapServer on its own with no caching. I'm confused.

Does anybody have any ideas? Perhaps I could look at and compare the TileCache and GeoWebCache requests in the server log? However, it seems that there may be something more fundamentally wrong if shp2img returns northing.

Regards,

John Westwood
Great Britain Historical GIS Project