[GRASS-user] aspect map with azimuth values

[Moritz Lennert]

On 2015-07-09 00:51, Glynn Clements wrote:
> Moritz Lennert wrote:
>
>> > how can I convert aspect map's values to azimuth values?
>> > or is there any way to create aspect map with azimuth values?
>>
>> I think this should work (but you should double check):
>>
>> if aspect <= 90, then azimuth = 90 - aspect
>> else: azimuth = 450 - aspect
>>
>> i.e.
>>
>> r.mapcalc "azimuth_aspect = if(aspect <= 90, (90 - aspect), (450 -
>> aspect))"
>
> Or:
>
> 	r.mapcalc "azimuth_aspect = (450 - aspect) % 360"


Even better, thanks !

Added as a FAQ [1] and to the r.slope.aspect manual (r65553).

Moritz

[1] http://grasswiki.osgeo.org/wiki/Transform_CCW_aspect_to_azimuth