I'm stymied trying to get output from r.param.scale that is equivalent to
the example on the bottom of the man page.
Resetting g.region to the input elevation map without any additional
options and adding a zmult factor of 5 appears to help. When the specified
param is 'features' I see what should be ridges and channels, but no peaks
or pits.
Changing the calculated param to either elev or profc yields blank maps
when I try to display them with d.rast.
Suggestions on how to properly apply this module will be very helpful.
On Thu, 28 Jan 2010, Rich Shepard wrote:
> I'm stymied trying to get output from r.param.scale that is equivalent
> to the example on the bottom of the man page.
Resetting g.region to the input elevation map without any additional
options and adding a zmult factor of 5 appears to help. When the specified
param is 'features' I see what should be ridges and channels, but no peaks
or pits.
Changing the calculated param to either elev or profc yields blank maps
when I try to display them with d.rast.
Suggestions on how to properly apply this module will be very helpful.
Are you working with data in a projected coordinate system? Are you x,y and z
coordinates all in the same units. What is the general nature of the terrain
you are looking at? Try adjusting the window size to get generalized
features-- remember that the quantification of terrain is a fractal problem.
Are you working with data in a projected coordinate system? Are you x,y
and z coordinates all in the same units. What is the general nature of the
terrain you are looking at? Try adjusting the window size to get
generalized features-- remember that the quantification of terrain is a
fractal problem.
Dylan,
All data are Oregon Lambert Conformal Conic. x,y distances are in metres,
z in international feet. I specify the zmult of 0.3048 or the module does
this automatically.
The drainage basin has an area about 12,000 acres. There are portions of
surrounding basins in the window, but I'm interested only in the one basin.
The attached screenshot has the DEM, basin boundaries, streams, and other
features too small to see at the reduced scale.
I'm stymied trying to get output from r.param.scale that is equivalent to
the example on the bottom of the man page.
Turns out it's all a matter of scale. When I zoom in to the specific area
of interest within the drainage basin the output map ('morphology') is much
better represented. Still doesn't show any peaks, saddles, or other
features, but that may be because the local topographic changes don't fall
within the algorithm's definitions.
