[gdal-dev] raster to polygon
Hi, Currently, I'm using gdal and ogr to convert a map after classification into a point shape file. Since the classification map typically consists of zones, a polygon shape file would make more sense. I'm wondering if anyone would know or share the idea of how to convert a map into a polygon shape file directly. Thanks Xiaodong ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] gdal_polygonize.py binding error
Hi, I just updated the older version of gdal (1.4.2) with the latest version of gdal (1.7.3) on x64 RedHat. Got an error when using gdal_polygonize.py for a test image gdal_polyzonize.py t2.tif -f "ESRI Shapefile" pt2 gdal.Polyzonize() not available. You are likely using "old gen" bindings or an older version of the next gen bindings. I found the previous threads on this issue, but could not find an answer. Any idea? Thanks Xiaodong ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] gdal_polygonize.py binding error
Hi Chaitanya, Setting PYTHONPATH did solve the problem. The new gdal-python bindings were installed under /user/local/lib64/python2.4/site-packages and the path was not set automatically. It would be nice if the sys.path is modified automatically by gdal installation. Thanks Xiaodong Xiaodong Zhang, Ph. D Associate Professor Department of Earth System Science and Policy University of North Dakota Tel: (701) 777-6087 http://www.und.edu/instruct/zhang On 1/6/2011 10:11 PM, Chaitanya kumar CH wrote: Xiaodong, Check again after setting the environment variable PYTHONPATH to the path to the new python bindings. On Fri, Jan 7, 2011 at 12:55 AM, Xiaodong Zhang mailto:xiaodong.zha...@und.edu>> wrote: Hi, I just updated the older version of gdal (1.4.2) with the latest version of gdal (1.7.3) on x64 RedHat. Got an error when using gdal_polygonize.py for a test image gdal_polyzonize.py t2.tif -f "ESRI Shapefile" pt2 gdal.Polyzonize() not available. You are likely using "old gen" bindings or an older version of the next gen bindings. I found the previous threads on this issue, but could not find an answer. Any idea? Thanks Xiaodong ___ gdal-dev mailing list gdal-dev@lists.osgeo.org <mailto:gdal-dev@lists.osgeo.org> http://lists.osgeo.org/mailman/listinfo/gdal-dev -- Best regards, Chaitanya kumar CH. /tʃaɪθənjə/ /kʊmɑr/ +91-9494447584 17.2416N 80.1426E ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] image operation over areas defined by a shapefile
Hi Gdal experts, First of all, happy holiday to all of you. Gdal-dev is really a wonderful learning platform (at least for me). I'm wondering if someone has done something like this and would like to share the experience. Say, I have an image, e.g. NDVI, and a shapefile define one or more areas (polygons) with the image. How to calculate the statistics for each area, for example, the mean value of NDVI within each polygon. Thanks Xiaodong -- Xiaodong Zhang, Ph. D Associate Professor Earth System Science and Policy University of North Dakota Tel: (701) 777-6087 http://www.und.edu/instruct/zhang http://www.und.edu/instruct/zhang ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] change the attribute values of a shapefile
Hi, I'm just wondering if any of you has done and would like to share your experience in replacing the attribute values of a shape file. Here is what I'm doing: 1. I have an image with pixels values ranging from, say, 1, 2, 3 and 4 2. I used gdal_polygonize.py to convert this into a polygone shape file, with attributes of 1, 2, 3 or 4. 3. Now I need to replace these attributes with a set new values, say, 10, 20, 30, and 40. Of course, I can do this in the first step, but I'm thinking the best way to do this is in the last step, because I can preserve the original image. Any suggestions? Thanks Xiaodong ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
[gdal-dev] acronym for OGR
Hi there, I have a simple question to ask: what does OGR stand for? Thanks Xiaodong ___ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
