[GRASS-user] find (x,y) index of data

Ken Mankoff mankoff at gmail.com
Thu Feb 4 16:55:13 PST 2016


I think I've solved this. I can compute i,j with:

On 2016-02-04 at 16:48, Ken Mankoff <mankoff at gmail.com> wrote:
> I'd like to do additional processing elsewhere (Python), outside of
> grass, based on the index (i,j) of each point in a raster. Is
> it possible to loop through the lon,lat or x,y coordinates in grass,
> perform a calculation, and then also generate the i,j grid index
> values for each point?

eval `g.region -pg`
r.out.xyz input=surf output=- fs=, | cut -d"," -f1-2 | while read -r line
  x=$(echo $line | cut -f1 -d,)
  y=$(echo $line | cut -f2 -d,)
  i=`echo "(($x)-($w))/$ewres"|bc`
  j=`echo "(($y)-($s))/$nsres"|bc`
  echo $x   $y   $i   $j


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