[GRASS-user] min and max coord values

[Glynn Clements]

temiz wrote:

> >> I want to get min and max coord values from  of catagorized raster
> >> map.
> >>
> >> something like:  r.stats -agn hey6 > gives minx maxx miny maxy
> >> is it possible  ?
> >>     
> >
> >
> > do you mean you want the coordinates of the bounding boxes surrounding
> > each category?
> >
> > loop over each CAT (`r.describe`), create a MASK or new map based on
> > that cat, then 'g.region -p zoom='.
> 
> thank you and other friends
> 
> I wrote a script to calculate the coordinates of  bounding box of each 
> category using "g.region -p zoom="
> 
> I am wondering if  "r.stats -agn"  is second alternative ?
> 
> My raster map is something like some islands.
> if I get coord value of each category , I can calculate most north- 
> south and, most west- east, and then determine the coords of  minimum 
> bounding  box?

This is more efficient, particularly for many categories, but it
requires a bit more work. The attached script takes the output from
"r.stats -gn" and computes the bounding boxes for each category, e.g.:

	r.stats -gn fields | ./bbox.awk | sort -n

-- 
Glynn Clements <glynn at gclements.plus.com>

-------------- next part --------------
#!/usr/bin/awk -f
{
	if ($3 in n)
	{
		if (n[$3] < $2) n[$3] = $2
		if (s[$3] > $2) s[$3] = $2
		if (e[$3] < $1) e[$3] = $1
		if (w[$3] > $1) w[$3] = $1
	}
	else
	{
		n[$3] = s[$3] = $2
		e[$3] = w[$3] = $1
	}
}

END {
	for (i in e)
		print i,n[i],s[i],e[i],w[i]
}