Re: [gdal-dev] substitute pixel values

[Joaquim Luis]

Sorry to come out so often with GMT solutions in this GDAL list but somethings are so trivial there. If you can trust that all your negative values are (mean)seawater, this will do the job grdclip yourGrid -Sb0/0 -Gclipped_grid.nc Note, one need the dev GMT5 version to read all grid formats through GDAL, otherwise (GMT4) "yourGrid" should be netCDF   Joaquim Michael, I'm not sure if you can do this using one of the existing utilities, you may be able to do this my creating a virtual file (gdalbuildvrt) and modifying it see - http://www.gdal.org/gdal_vrttut.html, but I have not attempted this.  An alternative is to do this using the API and something like numpy to choose and rewrite pixel values. See the following for a example in python http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/val_repl.py    On 9 January 2013 11:33, Smith, Michael <michael.sm...@maine.gov> wrote: I have some DEMs that are created from lidar.  For reasons related to seeing currents and wind effect, we did not ask for the water to be flattened, but rather it shows waves.  This is cool, and what we wanted.  BUT of course now we want to create a second set of DEMs with a  nice flat ocean.   I have numerous pixels out in the ocean which are slightly less than 0.  So how does one select out all pixels < 0 and substitute them with 0 with GDAL?    =============================== Michael Smith MS GISP State GIS Manager, Maine Office of GIS State of Maine, Office of Information Technology michael.smith _at_ maine.gov 207-215-5530 Board Member, Maine GeoLibrary Education Chair, Maine GIS Users Group State Rep, National States Geographic Information Council ***NOTE NEW ADDRESS*** State House Station 145 51 Commerce Drive Augusta, ME 04333-0145 69o 47' 58.9"W  44o 21' 54.8"N _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev

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