[GRASS-user] Sky-view Factor and GeoTiff Histogram equalization (stretch)
nik at nikosalexandris.net
Wed May 15 16:43:47 PDT 2013
Adrian Kirilov wrote:
> Hello to the GRASS users,
> Does anybody know how to equalize, or stretch, the histogram of a
In general, you can perform histogram equalisation on any GRASS raster map's
color table by using the "r.colors" module and instruct the "-e" flag. The "-
e" flag (quoting from its manual) "is designed to work with any color table,
both the floating point and the integer raster maps".
Please have a look in the manual (grass64):
<http://grass.osgeo.org/grass64/manuals/r.colors.html> (or grass70:
Note, this will operate on the color table associated with the raster map in
question. It wont affect the map's actual pixel values.
> The last represents Sky-view Factor based on a DEM model. It is
> well-known visualization technique when looking for archaeological
> I have to do *minimum-maximum stretch of the histogram with saturation
> of minimum*. How to do this in GRASS? Any help will be highly appreciated!
I don't know what the "...with a saturation of minimum" means. Maybe someone
else that understands this stuff better can help.
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