[Tilecache] problems getting tilecache.cfg and Openlayers WMS parameters in sync

[David Herbert]

Hello,

I have seen problems related to the ones I'm having on the list
already.  However, I seem to be going round in circles getting different
Tilecache errors each time.  Time to ask for help!  I downloaded the 1.9
distribution from SVN (the links on the website appear to be broken
today).  I am using Tilecache in CGI mode on Windows XP under Apache
2.2, and have made all the relevant changes to tilecache.cgi to reflect
my Python path (BTW I am a Java programmer and know next to nothing
about Python).  I have Geoserver WMS map layers (a base layer and a
number of overlays) which I wish Tilecache to cache.  Here are the
relevant bits of my tilecache.cfg:

[cache]
type=DiskCache
base=c:\temp\tilecache

[sggis:bathy_poly,sggis:coast_polygon]
type=WMSLayer
url=http://10.48.1.76:8080/geoserver/wms
layers=sggis:bathy_poly,sggis:coast_polygon
extension=png
bbox=-82000,7800,80000,116000
srs=EPSG:2007056

(my SRS is a recently defined one for the island of South Georgia in
the Southern Ocean - our local Geoserver has been modified to use it).

In Openlayers I have:

var sgStandardLayerOpts = {        
    'maxExtent' : new OpenLayers.Bounds(-82000,7800,80000,116000), 
    'maxResolution' : 'auto',
    'minResolution' : 0.5,
    'units' : 'm',    
    'projection' : EPSG:2007056
};

to initialise my map to the full extent of the enclosing <div>.  I am
not fussy about the set of resolutions or zoom levels.  When I bring up
my map, the following URL is fetched:

http://10.48.1.76/tilecache/tilecache.cgi?LAYERS=sggis%3Abathy_poly%2Csggis%3Acoast_polygon&STYLES=sggis_bathymetry_polygon%2Csggis_coastline&FORMAT=image%2Fpng&TRANSPARENT=off&SERVICE=WMS&VERSION=1.1.1&REQUEST=GetMap&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A2007056&BBOX=-133294.814815%2C59094.814815%2C-82000%2C110389.62963&WIDTH=256&HEIGHT=256

I can't understand where Tilecache is getting the bounding box it is
eventually giving to Geoserver.  It seems to be out of range.  I
currently get the error:

An error occurred: can't find resolution index for 200.370370.
Available resolutions are: 
[419.921875, 209.9609375, 104.98046875, 52.490234375, 26.2451171875,
13.12255859375, 6.561279296875, 3.2806396484375, 1.64031982421875,
0.820159912109375, 0.4100799560546875, 0.20503997802734375,
0.10251998901367187, 0.051259994506835938, 0.025629997253417969,
0.012814998626708984, 0.0064074993133544922, 0.0032037496566772461,
0.001601874828338623, 0.00080093741416931152]

from Tilecache when I put the above URL into a browser.

Any help greatly appreciated!

Thanks,

David Herbert
British Antarctic Survey.

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