John: Admittedly I work with GRASS solely on the text-based side - rarely if ever touching the GUI - but hopefully I can help:
1) To be honest, it's probably easiest to continue to use d.his and then display the resulting map using the GRASS plugin - QGIS doesn't really have many (if any?) raster tools, while GRASS was created primarily to deal with raster features (and added vectors later). 2) I believe r.mapcalc is the way to do this on the fly - not sure what you are asking, because I'm sure d.rast calls this "on the fly" when you go to display the image? You can always do something like r.mapcalc "{$output_map} = if({$input_map[0,0]} >= 3000, {$input_map[0,0]}, null())" so it doesn't stop the processing. 3. You CAN do raster reprojection on the fly. However, your results won't be anywhere near as "clean" as a vector reprojection as a result of the different format type. Also, there are some rules - I believe the projection has to be in the current region of the location you're reprojecting to, and also the resolution must be sufficient in order to handle the map. The r.proj part of the manual has two good procedures for doing so: http://grass.osgeo.org/grass64/manuals/html64_user/r.proj.html (old version but should still be okay) 4) I think it's an actual limitation - I am assuming, for a categorical map, you would like say all cats < 10 to have a transparency but all cats >= 10 to not have a transparency? I'm not sure how to do this, if this exists - I'd just use r.mapcalc and display two different layers. I hope I didn't misinterpret what you're writing, and hopefully that was of some help. Cheers John ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel