Reply-To: grassu-list@max.cecer.army.mil
Subject: reducing grid size of elevation data
Although I know it's not accurate to resample 30 m grid size elevation
data to 10 m grid size, I want to do this to improve my display since
other layers are 10 m grid size.
What is a good method for doing this? r.surf.idw etc. seem to assume
random points. I would like the center of each 9 cells that used to be
one cell to remain the same, and the outer 8 to become an averaged value
of their neighbors. I am thinking of using r.neighbors. Has anyone
done anything like this? I promise I will not claim that it is accurate
10 m elevation data -- it will just look a little better.
Thanks, Jane Rossing
r.neighbors is a good fast way of doing what you what. If your DEM is
exactly 30m n-s and e-w, all you need to do is:
g.region rast=DEM30
g.region res=10
r.neighbors in=DEM30 out=DEM10 method=average size=3
Spelling on my part is always subject to error.
Chuck Ehlschlaeger
Note: results will not be the same as an r.surface using the centers of
30 meter DEMs but "it will just look a little better".