[udig-devel] accuracy of GetFeatureInfo

[Bart van den Eijnden (OSGIS)]

Hi Jody,

the projections I am trying are both supported by the WMS.

Unfortunately I have no Java hosting, but it's a simple shapefile which 
can be set up with Geoserver. I am using 1.4.

The shapefile can be found here (200 Kb, native projection EPSG:28992, 
uDIG set to RD / New projection):

http://www.osgis.nl/lausanne/nl-prov.zip

An example request which uDIG is fyring off is (this request is really 
strange since the BBOX is not the BBOX of the map image shown anymore! 
and X and Y are always 1):

/geoserver/wms?Y=1&X=1&SERVICE=WMS&INFO_FORMAT=text/html&LAYERS=ogctestbed:nl-prov&FORMAT=image/png&HEIGHT=3&REQUEST=GetFeatureInfo&WIDTH=3&BBOX=188907.50415179788,391802.21024004533,192453.4125990071,395348.1186872545&SRS=EPSG:28992&QUERY_LAYERS=ogctestbed%3Anl-prov&VERSION=1.1.1 
HTTP/1.1" 200 447

Thanks in advance.

Best regards,
Bart

Jody Garnett schreef:
> Good question, it makes a direct call when able to make a direct 
> rendering of the WMS image (ie udig is using a coordinate system 
> supported by the WMS). In rare cases it may have to resample the image 
> onto the screen (making up for lack of WMS projections), we could 
> check that we back project the query into the coordinate space of the 
> original image... but as I recall I wrote this one and went to some 
> trouble to get it right.
>
> Can you point us at a service illustrating the problem, perhaps in a 
> jira report.
> Jody
>> Hi list,
>>
>> how accurate is uDIG with respect to GetFeatureInfo?
>>
>> I have tried it against 2 WMS's, Geoserver and Deegree, and at the 
>> borders of provinces, a lot of times the wrong element is returned. 
>> Ofcourse this could also be due to the WMS's.
>>
>> So I checked Gaia, and using Gaia it is very accurate for Geoserver, 
>> so I am assuming it is a uDIG problem.
>>
>> Any input appreciated.
>>
>> Best regards,
>> Bart
>>
>
>
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-- 
Bart van den Eijnden
OSGIS, Open Source GIS
http://www.osgis.nl