Hi Radim (and list), I have finally had the time to follow up on your suggestion, although I don't have the capacity to rebuild QGIS.
Using QGIS 1.6 I opened my grass raster layer and used the Info tool to query. I then opened a grass session and zoomed in on the same point (a pixel corner actually) and used the pixel query. The coordinates shown in QGIS differ from those in grass by about 3m in latitude (resolution of my data-set is 2m). However, when I tried to compensate (moving the cursor to the coordinates that grass showed) I still did not get the right result to my query in QGIS. Any ideas? Regards, Patrick -----Original Message----- From: Radim Blazek [mailto:radim.bla...@gmail.com] Sent: Wednesday, March 16, 2011 4:40 PM To: fg...@unam.na Cc: qgis-user@lists.osgeo.org Subject: Re: [Qgis-user] Zooming on raster maps - Identify error Hi, are you able to run QGIS compiled with debug support? With debug you can see debug output on terminal like: Debug: qgsgrass.cpp: 1072: (runModule) qgis.g.info info=query rast=align@alignment coor=69.5627,6.49715 Debug: qgsgrass.cpp: 1130: (getInfo) value:178.000000 As you can see, QGIS runs GRASS-QGIS module qgis.g.info to query values. Try to find if wrong coordinates are passed to qgis.g.info or qgis.g.info gives wrong values. If you cannot compile with debug output, try to verify if qgis.g.info module works correctly, you can run it as any other module in GRASS shell. Radim On Wed, Mar 16, 2011 at 11:15 AM, Dr. F. Patrick Graz <fg...@unam.na> wrote: > Hi Folks, > I have been using QGis (1.5 & 1.6) to view GRASS raster layers, and ran into > the following snag. > > When I zoom in to query the raster map (using Identify) I get the wrong > pixel value. I cross-checked the results in GRASS where the value is > correctly identified. > > I had rasterised a grid of lines (2x2m pixels). The pixel values running in > the north-south direction seem to be detected ok. The ones running east-west > are not. I assumed that there is some vertical off-set but I have not been > able to detect anything consistent. I have also cross-checked with a raster > layer with larger pixels - and there things work fine. > > Any guess as to what the issue might be? > > Patrick > ------------------------------------------ > Dr. F. Patrick Graz > Snr. Researcher, > Multidisciplinary Research Centre, > University of Namibia > > > > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user > _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user