dataset extents from MapServer CGI

[Jan Hartmann]

Frank,

For my part, I would at least like to be able to get the map extent, but 
I don't think implementing an extent query for separate layers would be 
much more difficult to program. You are right that WMS and WCS will give 
back the extent via a GetCapabilities request, but that is exactly the 
thing that I would like to do with native MapServer. I just want to be 
able, before I request the actual map, to get its extents via a separate 
call. AFAICS the problem is not so much implementing this functionality 
(it's already there for WMS and friends), but to agree how to send back 
the results (XML, GeoJSON, etc)

Jan

Frank Warmerdam wrote:
> Jan Hartmann wrote:
>> I second that question. If not, could it be implemented? Very useful 
>> feature
>>
>> Jan
>>
>> Bob Basques wrote:
>>> All,
>>>
>>> Is there any way to get a dataset extents from MapServer CGI directly 
>>> (no Mapscript)?
> 
> Jan / Bob,
> 
> How would you see this working?  Would it be a request made against a
> particular layer?  Against the map as a whole?  Internally in the code we
> have:
> 
> int msLayerGetExtent(layerObj *layer, rectObj *extent)
> 
> which calls the data source specific GetExtent function.  But I don't think
> this works for raster layers.  There is also msOWSGetLayerExtent() which
> first consults the layer metadata for extents.  Perhaps this would be the
> logical place to look?
> 
> Well, I suppose the other side of this is that for WMS and WCS the layer
> and coverage descriptions include extents already.  Is that sufficient for
> your needs?
> 
> Best regards,