Hi
Maybe it is not of importance, because no one else would use such extreme settings, but in case someone considers it as a bug:
I was testing a bit with v.outlier in GRASS 7 on dense LiDAR data (~4 points per m2).
When I use a very low Tykhonov regularization parameter (lambda_i) of 0.0000000000000000001 and rather short spline steps (1.5) at 0.5m resolution I get an error-message:
“Decomposition failed at row 16499 and col 0”
Stefan
Are those bare earth points only, or are you feeding it the entire point cloud?
On Fri, Dec 6, 2013 at 7:17 AM, Blumentrath, Stefan <Stefan.Blumentrath@nina.no> wrote:
Hi
Maybe it is not of importance, because no one else would use such extreme settings, but in case someone considers it as a bug:
I was testing a bit with v.outlier in GRASS 7 on dense LiDAR data (~4 points per m2).
When I use a very low Tykhonov regularization parameter (lambda_i) of 0.0000000000000000001 and rather short spline steps (1.5) at 0.5m resolution I get an error-message:
“Decomposition failed at row 16499 and col 0”
Stefan
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The opinions I express are my own and are not representative of the official policy of the U.S.Fish and Wildlife Service or Dept. of the Interior. Life is too short for undocumented, proprietary data formats.
I fed just points which where classified as “ground”, but which I know do contain vegetation…
Are those bare earth points only, or are you feeding it the entire point cloud?
On Fri, Dec 6, 2013 at 7:17 AM, Blumentrath, Stefan <Stefan.Blumentrath@nina.no> wrote:
Hi
Maybe it is not of importance, because no one else would use such extreme settings, but in case someone considers it as a bug:
I was testing a bit with v.outlier in GRASS 7 on dense LiDAR data (~4 points per m2).
When I use a very low Tykhonov regularization parameter (lambda_i) of 0.0000000000000000001 and rather short spline steps (1.5) at 0.5m resolution I get an error-message:
“Decomposition failed at row 16499 and col 0”
Stefan
grass-dev mailing list
grass-dev@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-dev
–
Doug Newcomb
USFWS
Raleigh, NC
919-856-4520 ext. 14 doug_newcomb@fws.gov
The opinions I express are my own and are not representative of the official policy of the U.S.Fish and Wildlife Service or Dept. of the Interior. Life is too short for undocumented, proprietary data formats.
On Fri, Dec 6, 2013 at 1:17 PM, Blumentrath, Stefan
<Stefan.Blumentrath@nina.no> wrote:
Hi
Maybe it is not of importance, because no one else would use such extreme
settings, but in case someone considers it as a bug:I was testing a bit with v.outlier in GRASS 7 on dense LiDAR data (~4 points
per m2).When I use a very low Tykhonov regularization parameter (lambda_i) of
0.0000000000000000001 and rather short spline steps (1.5) at 0.5m resolution
I get an error-message:“Decomposition failed at row 16499 and col 0”
I found similar errors with very small lambda values, i guess it's
some floating point precision limit. It seems that lambda should not
be much smaller than 0.0001. For v.outlier, I would leave lambda at
the default and rather use shorter spline steps, if you want to
fine-tune the results.
Markus M