[GRASS-user] raster map of the azimuth to a point

[ivan marchesini]

This is my solution at the moment:


given a point of coordinates x,y

_____________
r.mapcalc "px=(x()-x)"
r.mapcalc "py=(y()-y)"

r.mapcalc "azimuth=if(px>=0 & py>=0,90-atan(py/px),if(px>=0 &
py<0,90-atan(py/px),if(px<0 & py<0,270-atan(py/px),if(px<0 &
py>=0,270-atan(py/px)   ))))"
_____________


cheers

Ivan



Il giorno ven, 06/02/2009 alle 14.27 +0100, ivan marchesini ha scritto:
> Dear Grass Users,
> I have a single point vector map.
> 
> I would like to obtain a raster map where each cell represents the value
> of the azimuth to the point raster map.
> I mean I would like to know which direction someone have to look to see
> the point in the vector map.
> 
> any suggestion?
> 
> many thanks 
> 
> Ivan
> 
> 
> 
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Ivan Marchesini
Department of Civil and Environmental Engineering
University of Perugia
Via G. Duranti 93/a 
06125
Perugia (Italy)
Socio fondatore GFOSS "Geospatial Free and Open Source Software" http://www.gfoss.it
e-mail: marchesini at unipg.it
        ivan.marchesini at gmail.com
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