[GRASS-user] r.composite giving unexpected results

I am trying to use r.composite to make a shaded relief raster I can export for presentation purposes. I am using r.his to generate the RGB channels based off of a shaded relief map for intensity and an NLCD raster as the hue. However, the results are very unexpected and the RGB values to not appear to be mapping to the output.

For example, a composite of RGB maps of 171:171:171 , 112:112:112, and 40:40:40 , respectively, which are just the RGB components of the NLCD map (NLCD Class 82, cultivated crops). R.composite sets the color table to rainbow and yields a pixel with a value of 5589. The intensity map can vary and still yield the same r.composite value. I am using the default levels value of 32. Levels=255 seems to crash GRASS

Any ideas as to what I may be doing wrong in making the composite or if I am using the correct method?

Alex

On Wed, Sep 19, 2018 at 10:41 PM Moody, Alex <Alex.Moody@idwr.idaho.gov> wrote:

I am trying to use r.composite to make a shaded relief raster I can export for presentation purposes. I am using r.his to generate the RGB channels based off of a shaded relief map for intensity and an NLCD raster as the hue. However, the results are very unexpected and the RGB values to not appear to be mapping to the output.

Please take a look a the dedicated command:
https://grass.osgeo.org/grass74/manuals/r.shade.html

best,
Markus