Hello,
On Fri, May 13, 2011 at 4:00 PM, Frank Warmerdam <warmer...@pobox.com> wrote: > On 11-05-13 06:51 AM, Jorge Arévalo wrote: >> >> Hello, >> >> Is there any reason to limit the GDALPolygonize function to read data >> in int32 buffers, instead of using 32b float or even 64b double ones? >> As I stated in ticket #4005 (http://trac.osgeo.org/gdal/ticket/4005), >> I want to code an alternative version using these kind of buffers. But >> I don't know if I'm missing something. > > Jorge, > > There are no *compelling* reasons to limit polygonization to integer > data, but once you get into floating point data lots of questions do > arise about value comparisons will be done - will it be a "within > epsilon" sort of test or are you looking for exact floating point matches? > I'm using the AlmostEqual2sComplement function from http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm to float comparison. Do you think it's a good approach? > If a floating point option is available, I think there will still need to > be a version of the algorithm operating on integer buffers to avoid > problems representing some integer values in floating point and potentially > more expensive comparisons. > Of course. I've created new algorithms for this (most of the parts cloning the original ones). I'ts kinda duplicating code, but I don't want to interfere with the original functions. > That said, I'm ok with extending the function to support floating point > bands. > Good :) > Best regards, > -- > ---------------------------------------+-------------------------------------- > I set the clouds in motion - turn up | Frank Warmerdam, > warmer...@pobox.com > light and sound - activate the windows | http://pobox.com/~warmerdam > and watch the world go round - Rush | Geospatial Programmer for Rent > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev > Best regards, -- Jorge Arévalo Internet & Mobilty Division, DEIMOS jorge.arev...@deimos-space.com http://es.linkedin.com/in/jorgearevalo80 http://mobility.grupodeimos.com/ http://gis4free.wordpress.com http://geohash.org/ezjqgrgzz0g _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
