[GRASS-user] Multidirectional hillshading scripts / addons?

[Markus Neteler]

Hi HB,

Here is one more:

r.shaded.pca - Creates relief shades from various directions and
combines them into RGB composition.
https://grass.osgeo.org/grass8/manuals/addons/r.shaded.pca.html

Best
Markus

On Fri, Feb 16, 2024 at 11:20 PM B H via grass-user
<grass-user at lists.osgeo.org> wrote:
>
> Hi,
> I am trying to create a hillshading effect using DEM rasters similar to ESRI multidirectional hillshading, but I am unable to get anything  in. grass to perform as good as ESRI (or even gdaldem multidirectional shading).
> I am hoping someone in this group has some scripts /addon/tips that I can try.
>
> So far I have tried the following on a few DEMs ( from 3m  to 100 m grid sizes).
> 1) gdaldem  multidirectional hillshading : It's not grass based, but so far has performed better than other grass options :  with the parameter zfactor between 1 and 10. But  it does not seem to be quite as good as ESRI.
> 2) Following code is based on some old discussion on this email list.(Its seems to exaggerate the hills and valleys more than I would expect)
> https://gist.github.com/amcox/b54d65f08fe4448840462901fd6350d4
> 3) Other variants of hillshading like r.skyview : Tried with several parameters but it seems to be inferior to gdaldem (It seems to be a 'washed out' version of the multidirectional. hillshading).
>
> Thanks,
> HB
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-- 
Markus Neteler, PhD
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