[mapserver-users] WMS BBOX tolerance out of this world?

[Charlton Galvarino]

Hi, all.  I'm hoping that someone knows this answer off the top of their head so I won't have to sort through mountains of OGC specs.  That's the lazy developer in me.

Let's say we're dealing w/ epsg 4326.  We as humans (some mostly human) know that this generally means -180,-90,180,90.  Or perhaps sometimes 0,-90,360,90.

My question is, does the WMS server need to support queries outside of these bounds?  E.g. for a dataset advertised as 4326 w/ bounds -180,-90,180,90, if the user requests -198,-99,198,99, should the user get the 'data' image surrounded by white space or get an error that says 'sorry, that was something I don't understand'?  A GetCaps can advertise the BBOX for the site and each layer, but I'm still asking about these exceptional cases.

I dug around and found that both ESRI and MapServer WMS servers support these queries just fine.  But are they being nice, or does the WMS spec say that these are valid queries and that the servers should support them?

Many TIA,

Charlton

Examples of ESRI & MapServer queries.  Apologies if the URL's get chopped up in listserv land.

ESRI world
http://toposervices.cr.usgs.gov/wmsconnector/com.esri.wms.Esrimap/USGS_EDNA_geo?LAYERS=Counties&FORMAT=image%2Fpng&TRANSPARENT=true&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4326&BBOX=-180,-90,108,90&WIDTH=360&HEIGHT=180

ESRI world + 10% in all directions
http://toposervices.cr.usgs.gov/wmsconnector/com.esri.wms.Esrimap/USGS_EDNA_geo?LAYERS=Counties&FORMAT=image%2Fpng&TRANSPARENT=true&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4326&BBOX=-198,-99,198,99&WIDTH=360&HEIGHT=180

MapServer world
http://disc1.sci.gsfc.nasa.gov/daac-bin/wms_airs?LAYERS=AIRX3STD_SURFPRES_D&FORMAT=image%2Fpng&TRANSPARENT=true&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4326&BBOX=-180,-90,108,90&WIDTH=360&HEIGHT=180

MapServer world + 10% in all directions
http://disc1.sci.gsfc.nasa.gov/daac-bin/wms_airs?LAYERS=AIRX3STD_SURFPRES_D&FORMAT=image%2Fpng&TRANSPARENT=true&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&STYLES=&EXCEPTIONS=application%2Fvnd.ogc.se_inimage&SRS=EPSG%3A4326&BBOX=-198,-99,198,99&WIDTH=360&HEIGHT=180





Charlton Galvarino
1 (803) 233-6205 : voice
1 (803) 223-9579 :   fax
charlton at 2creek.com

P.O. Box 50960
Columbia, SC 29250