[gdal-dev] Re: Ogr2ogr, WFS 1.1.0, -spat and gml:Box
jukka.rahkonen at mmmtike.fi
Mon Jan 9 05:12:51 EST 2012
Even Rouault <even.rouault <at> mines-paris.org> writes:
> > So it is WFS 1.1.0 request with the BBOX filter. But is it OK to give BBOX
> > as GML2 gml:Box if the service is WFS version 1.1.0? I have been thinking
> > it should be using GML3 and gml:Envelope instead.
> I suppose you're right. I didn't recall all the details, so I had a look at
> the code, and here's the answer :
> /* This is a heuristic to detect Deegree 3 servers, such as */
> /* http://deegree3-demo.deegree.org:80/deegree-utah-demo/services */
> /* that are very GML3 strict, and don't like <gml:Box> in a <Filter><BBOX>
> /* request, but requires instead <gml:Envelope>, but some servers (such as
> MapServer) */
> /* don't like <gml:Envelope> so we are obliged to detect the kind of
> server */
> So basically it seems that most servers are tolerant and will accept gml:Box.
> But some servers that should accept gml:Envelope don't. So the default
> behaviour is to use gml:Box, except in cases where we know it won't be
> accepted (but the server mentionned in the comment is no longer online, and I
> cannot find another one that doesn't accept <gml:Box>)
> It would perhaps be more reasonable to implement the reversed logic from a
> theoretical point of view, but unless you can point me to a server that
> doesn't like the current logic, I'm quite hesitant to change that
The deegree3 demos can be found here http://demo.deegree.org/ and the Utah demo
seems to be at http://deegree3-demo.deegree.org:80/utah-workspace/services
I had a quick test and it did not complain about using <gml:Box> in <Filter>.
The result looks like correct, too. So perhaps we can conclude that using
<gml:Box> with WFS 1.1.0 filters is probably wrong but because it works then it
will not be fixed.
I do not really like this ambiguous behaviour, though. Now for example WFS 1.1.0
bounding box guery with GDAL and EPSG:4236 leads to a mixture of using GML2
<gml:Box> that does not exist in GML3 but with a GML3 style Northing-Easting
coordinate order. However, normal GDAL user does not ever see it without
sniffing the web traffic and there is really nothing new with WFS being ambiguos
so perhaps I just need to take everything that is added to the stew and try to
remember all the tricks and pecularities while waiting for some comfortable
vector delivery service to appear.
More information about the gdal-dev