I'm using a program that generates a map using a set of colors (radio signal strength ranges, to be specific). It outputs the file as a jpg image with KML, so it displays perfectly well in Google Earth and in any photo viewer. But when I try to read it into QGIS (I've got 3.2 installed now), the raster processing functions seem to demand that they take over and replace the colors. Using palleted unique values, I was able to painstakingly regenerate something close to the original, but none of the options seem to just want to display the colors as the jpg file shows them.

Is there a trick I'm missing?

  • 1
    Add gdalinfo report about your jpg. Even better if you can share one for testing. – user30184 Jul 22 '18 at 7:51
  • I'm not sure where the gdainfo report would be. I'm just learning QGIS; my usual GIS is MapInfo. That doesn't do fancy raster stuff, but once you register a picture it shows in its own colors. QGIS does report this: Width 1800 Height 1790 Data type Byte - Eight bit unsigned integer GDAL Driver Description VRT GDAL Driver Metadata Virtual Raster Dataset Description D:\TEMP\Otelco\CBRS-allnodes.kml Compression Band 1 STATISTICS_MAXIMUM=113 STATISTICS_MEAN=10.414716561128 STATISTICS_MINIMUM=0 STATISTICS_STDDEV=5.6989374677964 – Fred Goldstein Jul 22 '18 at 16:39
  • Is there a setting that just displays jpg rasters without trying to interpret them? – Fred Goldstein Jul 23 '18 at 13:54
  • Does your image really have just one band? Does the KML part contain the palette? – user30184 Jul 23 '18 at 20:15
  • I assume it has one band, but I don't really understand how bands work -- RadioMobile produces the picture (can also be PNG -- that may work a bit better?) and every other program just displays it. The KML only contains the boundaries. I think there's a general issue here that QGIS is using raster palettes to encode information, not just display the presented colors, which I want. – Fred Goldstein Jul 24 '18 at 22:14

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