Here's another fun way of mapping airspace: You can get sectional charts in the form of .tif files from: http://www.aeronav.faa.gov/index.asp?xml=aeronav/applications/VFR/chartlist_sect
You can then read them into QGIS ... and then overlay them with whatever other information you want, perhaps from apt.dat and nav.dat and/or elsewhere. (Reading the same .tif file into GRASS doesn't work. GRASS tries and fails, with no error or warning messages. The resulting map has no pixels at all, according to d.histogram. So this is another reason to use QGIS.) On 09/21/2011 06:10 PM, J. Holden wrote: > Admittedly I work with GRASS solely on the text-based side - rarely > if ever touching the GUI Roger that. I, too, rely almost exclusively on the command-line interface to GRASS. I occasionally use the GUI to give me hints about what CLI commands I need to use. The stuff I need to do involves so many GRASS commands that I could not possibly remember them all, let alone do them reliably, so I use a script. > I hope I didn't misinterpret what you're writing, and hopefully that > was of some help. You definitely understood the questions (even though I now realize the questions were not entirely clear) ... and you have been very helpful. > 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. Well, YMMV but I can't get the instance I'm running to do raster reprojection. It tries and fails. I have an example where there are two rasters in the same location, with slightly different projections, plus some vector data. If I switch projections in my "project" workspace, one raster or the other goes to all-white. The "zoom to layer" button zooms to the right place, but the image is still all-white. The vector data stays where it belongs, so that is working. This is a low priority for me, because I am content to reproject all rasters to a common SRS using gdalwarp. That does everything I need it to do. > 1) 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). That sounds good, but I haven't figured out how to get a map /out/ of d.his. I think of d.his as a display function, not a map-calculation function. I don't know how to find the "resulting map" produced by d.his, not in any useful form anyway. And here is a possibly-related question: what colormap are the Sectional Aeronautical Charts using, and how do I specify it? They show up in QGIS in beautiful natural color. In particular, in QGIS, if I change the colormap on one of those charts, there does not appear to be any way to change it back to the beautiful original colormap. I assume there is some clever colormap that the QGIS backend knows about but the GUI does not. I mention this because I reckon I could solve several interesting problems by using this colormap, using r.mapcalc if necessary to format the pixels. This includes the "drape" operation, which produces very nice-looking results by taking the hue from one layer and the intensity from another. Or maybe somebody can write a r.calc.drape module. ------------------------------------------------------------------------------ All of the data generated in your IT infrastructure is seriously valuable. Why? It contains a definitive record of application performance, security threats, fraudulent activity, and more. Splunk takes this data and makes sense of it. IT sense. And common sense. http://p.sf.net/sfu/splunk-d2dcopy2 _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
