[GRASS-user] aspect claculations with integer and float rasters

[Carlos Grohmann]

Hi Hamish, thanks for the quick reply.

Well, I think this is not related to output but to _input_. It's as
r.slope.aspect doesn't care if the input is integer or float, so the
output aspect always has the artifacts.

I tried using 'prec=float' (or double) and it makes no difference.

I also cannot try r.param.scale because it doesn't work in lat/long locations :(

best

Carlos



On Sun, Sep 16, 2012 at 10:50 PM, Hamish <hamish_b at yahoo.com> wrote:
> Carlos wrote:
>> I'm a bit annoyed by some aspect maps here. Using SRTM in a
>> lat/long location, aspect presents the
>> usual artifacts at 0, 45, 90, etc. So I tried to convert it
>> to float, but using new = old * 1.0
>> in mapcalc didn't worked (I can swear it worked before), so
>> I used new = old + 0.00001
>>
>> and then I ran r.slope.aspect again, but my aspect raster
>> still shows the artifacts.
>
> maybe something to do with
>   https://trac.osgeo.org/grass/ticket/1728
> ?
>
> can you try the r.slope.aspect 'prec=float' option?
>
> does an aspect map made with r.slope.param look any better?
>
>
> Hamish



-- 
Prof. Carlos Henrique Grohmann
Institute of Geosciences - Univ. of São Paulo, Brazil
- Digital Terrain Analysis | GIS | Remote Sensing -

http://carlosgrohmann.com
________________
Can’t stop the signal.