I have download the following Landsat 7 image


I want to open a true color RGB composition using bands 1, 2 and 3. For that, I import the Tiff files of the bands. When a create the RGB composition (raster, miscellaneous, virtual raster) the result does not look very nice. My issue is not that the image is dark (there is a lot of ice/snow) but that the true colors are not very accurate. Water looks purple, glaciers have some purple areas, etc. Am I missing something to create a good looking true color RGB?

enter image description here

The output should look like this

enter image description here

-- EDIT --

enter image description here

  • @radouxju, my issue is not that much that the image is dark but the rgb colors are not correct. (e.g. water as purple). – GCGM Dec 11 '17 at 10:47
  • @MikkelLydholmRasmussen, I am using landsat 7, bands 1,2,3 should be blue, green, red respectively – GCGM Dec 11 '17 at 10:47
  • this could be linked with the difference in contrast for each band. I don't have the data but I am pretty sure that you could modify the colors by changing the contrast (presence of snow messes up the contrast). – radouxju Dec 11 '17 at 11:05
  • @radouxju, Thank you for your suggestion. I have been playing with the contrast in the color rendering section. I have try also to change the min / max values of the bands. Although the appearance changes and improves (as suggested in the link you posted before) the colors are not natural. Same issue with the purple water, green colors in areas where it should be bare soil, etc. – GCGM Dec 11 '17 at 11:17
  • try to take a subset of an area without glacier, and see how the histograms look like. – radouxju Dec 11 '17 at 11:29

The order of bands for the true color composite should be B3,B2,B1. You could try to create a virtual raster using GDAL:

gdalbuildvrt -separate LE07_L1TP_231095_20011014_20170202_01_T1_RGB.vrt LE07_L1TP_231095_20011014_20170202_01_T1_B3.tif LE07_L1TP_231095_20011014_20170202_01_T1_B2.tif LE07_L1TP_231095_20011014_20170202_01_T1_B1.tif

The image LE07_L1TP_231095_20011014_20170202_01_T1_RGB.vrt looks as expected in QGIS.

Landsat 7 true color - B3,B2,B1

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  • I just did it again and now it's showing the proper colors. Cannot tell what I did differently but your answer may help others. Thanks – GCGM Dec 11 '17 at 12:20

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