Ok, crazy buffering removed. uDig should make sane WMS GetFeatureInfo requests now. This is on trunk, and will be reflected in the release we are trying to put out (later today).
It definitely needs some testing, in particular when both client and server side reprojection are involved. (The fix was written in haste and may not be perfect) Bart, are you able to test it once we have a release ready? Richard On Tue, 2006-05-09 at 19:42 +0200, Bart van den Eijnden (OSGIS) wrote: > uDIG requests a 3x3 image. And then it requests the topleft pixel (X=1, > Y=1). > > I don't know the internals ofcourse, but should it not request the > center pixel (X=2, Y=2)? At least that gives the correct results for my > testcase :-) > > Why else would it request 3x3, it might as well request 1x1 or 2x2 if it > is using the topleft pixel. > > Best regards, > Bart > > Jody Garnett schreef: > > In that case we will need to ask Richard to implement a different > > plugin for the InfoTool for each renderer he creates. Not fun but > > possible. I did think he ended up making a 2x2 reference image and > > selecting the first pixel (after having a few WMS fail on a 1x1 image > > reference image. > > Jody > >> > >> I think the problem with this approach, as now demonstrated, is that > >> it doesn't work :) It might take something a little more > >> "arbitrary", like a pretend image of "about 300 pixels in size" with > >> the click point in the "middle of that image" to get a > >> correct-seeming answer. Sending back a one-pixel map with a click > >> "on the pixel" is begging to hit corner cases in the WMS server side > >> code. > >> > >> On 5-Sep-06, at 12:29 AM, Jody Garnett wrote: > >> > >>> Ah, interesting question ... because of a difference between what we > >>> display and what we requested from the WMS. > >>> - often we will have to make several requests and tile content onto > >>> the screen in WMS happy chunks, > >>> - or we will need to make slightly larger requests and resample them > >>> onto the screen (as mentioned previously). > >>> > >>> It was just easier to back project a pixel and use it to make a > >>> request in the correct location once, rather then trying to reverse > >>> several rendering process es to exactly match the original request > >>> (aka the approach we used for uDig 0.8). > >>> > >>> Cheers, > >>> Jody > >>>> Hi Jody, > >>>> > >>>> why did you end up changing the BBOX and width/height client-side? > >>>> Why not leave it up to the WMS server like Gaia does? > >>>> > >>>> Best regards, > >>>> Bart > >>>> > >>>> Jody Garnett schreef: > >>>>> Indeed, we eventually figured out that WMS getInfo is considered a > >>>>> check in the center of a single pixel. > >>>>> > >>>>> Thinking, > >>>>> > >>>>> Richard for a while we forced the renderers to leave us a hook so > >>>>> we could make our info request, is there any way we can ask the > >>>>> WMS renderers to leave some hints on the layer blackboard about > >>>>> the image rendered? The same plugin making the rendering > >>>>> contribution can provide the hint ... > >>>>> > >>>>> Jody > >>>>>> 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 > >>>>>>>> > >>>>>>> > >>>>>>> > >>>>>>> _______________________________________________ > >>>>>>> User-friendly Desktop Internet GIS (uDig) > >>>>>>> http://udig.refractions.net > >>>>>>> http://lists.refractions.net/mailman/listinfo/udig-devel > >>>>>>> > >>>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>> > >>>>> _______________________________________________ > >>>>> User-friendly Desktop Internet GIS (uDig) > >>>>> http://udig.refractions.net > >>>>> http://lists.refractions.net/mailman/listinfo/udig-devel > >>>>> > >>>>> > >>>> > >>>> > >>> > >>> > >>> _______________________________________________ > >>> User-friendly Desktop Internet GIS (uDig) > >>> http://udig.refractions.net > >>> http://lists.refractions.net/mailman/listinfo/udig-devel > >> > >> _______________________________________________ > >> User-friendly Desktop Internet GIS (uDig) > >> http://udig.refractions.net > >> http://lists.refractions.net/mailman/listinfo/udig-devel > > > > > > _______________________________________________ > > User-friendly Desktop Internet GIS (uDig) > > http://udig.refractions.net > > http://lists.refractions.net/mailman/listinfo/udig-devel > > > > > > _______________________________________________ User-friendly Desktop Internet GIS (uDig) http://udig.refractions.net http://lists.refractions.net/mailman/listinfo/udig-devel
