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Hello
I have some problems with the toposhape module. I've been trying to use
it on a DEM, going all the way to Pellegrini's Ph.D. thesis (cited as
module source) to understand the nuts and bolts of it.
Nontheless I am having serious problems applying the module.
First I've run the module on a raw DEM, obtaining dismal results:
inflection hillsides and ravines seem to dominate, and it doesn't
reflect at all what you would interpeter visually from the DEM. Assuming
it to be a scale problem, I tried to use a Butterworth filter in FFT to
smooth the DEM removing the high frequency components, as suggested by
the help module. Since my DEM is not the size of a power of 2, I used
zero padding.
Wrong move: the effect of reverse transformation of a zero padded image
is the production of heavy ringing at the edge between the image proper
and the zero pads.
Any suggestions? other experiences?
Marco
--
Marco Albani, Ph.D. Candidate
Department of Forest Sciences
University of British Columbia
Vancouver, BC - Canada.
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