Paul W. Box writes:
I would like to know if there is a straightforward way to do this. I
would like to take a least-cost path route created by r.drain, and
export the results to a simulation in the form of a list of cells or
lat-long coordinates. For example, if r.drain is used to calculate the
least cost path between two cells, then I would like to get a list of
the individual cells that the path crosses in the order that they're
crossed.
Take the raster output by r.drain in which the least cost path will be 1's
and all other cells will be zero's and run:
'r.stats -1 -g -x -z input=drainfile fs=, output=outfile'
Note: -1 outputs the data for each cell one per line
-g prints the grid coords east,north for each cell
-x prints the x and y (column and row) values for each cell
-z zero cells will not be reported
fs is the file column separator you need ie. , | or ' ' etc
outfile will contain the locations one per line but I don't
think they will be in path order. If the path does
not turn back on itself ie either N or E always increasing
or decreasing then a sort will get them in order.
If this is not true then you will have to write a little?
routine that given the start pixel coord traverses the list looking for
the neighbouring/nearest pixel in the list etc.
If you just need the actual path then you could run r.poly on the 'drainfile'
and get back a vector file of the least cost path.
regards
Rod Paterson
Aberfoyle Resources Ltd
Level 31
525 Collins Street
Melbourne Vic., 3000
Phone: 61-3-92706666
Fax: 61-3-92706699
Email: rgp@aberfoyle.oz.au