Hi John,<br><br>I wrote a very un-optimized tool to do this a little while ago. It's a Python script that you can probably run in FWTools. Just be sure that you put it in your FWTools/bin directory, and then that you create an appropriate environment setting script with the same name in FWTools/bin_safe. Just do a search for gdal_merge.py and you'll see what I mean.<br>
<br>You'll need to do some editing of the script to specify the pixel values you want to vectorize, but that should be pretty straight-forward.<br><br>Good luck, and let me know if you need any help getting it to run.<br>
<br>Roger<br>--<br><br><div class="gmail_quote">On Wed, Apr 8, 2009 at 8:03 PM, John Zastrow <span dir="ltr"><<a href="mailto:jcz@northredoubt.com">jcz@northredoubt.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
We need to vectorize a large class raster (landuse) that we produced<br>
using spatial analyst. ArcGIS is refusing to take it further and our<br>
friends at ESRI are stumped. So, we are ready throw some FOSS tools at<br>
the problem and the next step is to simply vectorize about 12 raster<br>
classes into a vector that we'll clean up from there. I think<br>
gdal_polygonize (<a href="http://www.gdal.org/gdal_polygonize.html" target="_blank">http://www.gdal.org/gdal_polygonize.html</a>) will help me<br>
get the product out. But, I tried two types of FWtools installs for<br>
Windows (osgeo and maptools) and was bitten by the "old gen" problem<br>
with each.<br>
<br>
I'll happily kick over to Ubuntu-based linux or keep on Windows if<br>
someone can recommend a surefire way to get gdal_polygonize running<br>
quickly - or recommend a replacement.<br>
<br>
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</blockquote></div><br>