[gdal-dev] substitute pixel values

Travis Kirstine traviskirstine at gmail.com
Wed Jan 9 08:53:28 PST 2013


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.Smith at 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
> ****[image: icons]
>
> ***NOTE NEW ADDRESS***
>
> State House Station 145
> 51 Commerce Drive
> Augusta, ME 04333-0145
> 69o 47' 58.9"W  44o 21' 54.8"N****
>
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