[OpenLayers-Users] Bad Bounding box request

[Ben Madin]

G'day all,

I am getting the hang of OpenLayers & tilecache, but have noticed some 404 errors creeping into my apache access logs.

After fixing most of them, I'm still noticing these odd ones (500, 404) consistently occurring.

xyz.xyz.xyz.xyz - - [12/Feb/2010:01:57:11 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=countries&ISBASELAYER=true&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=92.74999936,-3.5527136788005e-15,103.99999872,11.24999936&WIDTH=256&HEIGHT=256 HTTP/1.1" 500 68919
xyz.xyz.xyz.xyz  - - [12/Feb/2010:01:57:11 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=countries&ISBASELAYER=true&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=81.5,0,209.5,128&WIDTH=256&HEIGHT=256 HTTP/1.1" 404 177
xyz.xyz.xyz.xyz  - - [12/Feb/2010:01:57:11 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=countries&ISBASELAYER=true&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=87.12499968,11.24999936,92.74999936,16.87499904&WIDTH=256&HEIGHT=256 HTTP/1.1" 200 4435
xyz.xyz.xyz.xyz  - - [12/Feb/2010:01:57:11 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=countries&ISBASELAYER=true&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=109.6249984,16.87499904,115.24999808,22.49999872&WIDTH=256&HEIGHT=256 HTTP/1.1" 200 42407


If I zoom in, mostly fine, but 

xyz.xyz.xyz.xyz - - [12/Feb/2010:02:08:18 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=urban&GRAPHID=1&ISBASELAYER=false&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=89.93749952,22.49999872,92.74999936,25.31249856&WIDTH=256&HEIGHT=256 HTTP/1.1" 200 1096
xyz.xyz.xyz.xyz - - [12/Feb/2010:02:08:18 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=countries&ISBASELAYER=true&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=113.5,0,145.5,32&WIDTH=256&HEIGHT=256 HTTP/1.1" 404 176
xyz.xyz.xyz.xyz - - [12/Feb/2010:02:08:18 +1000] "GET /tilecache/tilecache.py?TRANSPARENT=true&LAYERS=countries&ISBASELAYER=true&VERSION=1.1.1&SRS=EPSG%3A4326&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&FORMAT=image%2Fpng&BBOX=81.5,0,113.5,32&WIDTH=256&HEIGHT=256 HTTP/1.1" 404 176


So, in summary:

If the request BBox is too big I get a 404 - ie if it is  81.5,0,209.5,128

An error occurred: can't find resolution index for 0.062500. Available resolutions are: 
[0.0439453125, 0.02197265625, 0.010986328125, 0.0054931640625, 0.00274658203125, 0.001373291015625, 0.0006866455078125, 0.00034332275390625]

If the request BBox is overdetailed I get a 500 error - ie 92.74999936,-3.5527136788005e-15,103.99999872,11.24999936


The map definitions are :

 maxResolution: '0.04394531',
 numZoomLevels: 8,
 maxExtent: new OpenLayers.Bounds(81.5,0,126.5,30),

OpenLayers 2.8 (locally installed version (June 2009)
TileCache 2.10 (Python)
MapServer 5.4 (for WMS) on FreeBSD 7


It seems to be mainly working? is this a bug (the bbox size)?, or something I have overlooked

cheers

Ben