Feature #830

grdimage, clipping

Added by Mark over 2 years ago. Updated over 2 years ago.

Status:ClosedStart date:2015-12-04
Priority:NormalDue date:
Assignee:Paul% Done:


Target version:Candidate for next bugfix release
Platform:Mac OS X


Every once in awhile, I stumble on a case where grdimage shows black pixels for a grd file. It usually takes me a while remember that this will happen in some cases where the spline interpolation scheme generates values that are out of range relative to the range of the input data. There is a useful discussion in the documentation about this issue (see "Consequences of grid resampling"). Of the two recommended solutions, the second one, setting the clipping option via -n+c, has generally worked best for me. That said, I usually spend a bunch of time thinking that there is something wrong with the input data. I now recognize that grdimage generates a brief warning about this issue when it happens, noting that some of the generated values are out of range. It would really help if that warning included a recommendation to set -n+c so that those out of range values are clipped.


Associated revisions

Revision 15325
Added by Paul over 2 years ago

Improve warning message for -n+c, i.e., issue #830


#1 Updated by Paul over 2 years ago

  • Tracker changed from Bug to Feature
  • Status changed from New to Resolved
  • Assignee set to Paul
  • Target version set to Candidate for next bugfix release

I have added a message so that if we by resampling exceed the input range and -n+c is not in effect then we get a new warning "See option -n+c to clip resampled output range to given input range". In r15325.

#2 Updated by Mark over 2 years ago


#3 Updated by Paul over 2 years ago

  • Status changed from Resolved to Closed

Time to close this puppy.

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