All,
I need to create image footprints (outlines excluding the nodata
areas) for about 300 geotiff images. While GDAL's gdal_polygonize.py
may do the job, I prefer GINA's
(http://www.gina.alaska.edu/projects/gina-tools) gdal_trace_outline
because of its option,s but I'm open to alternatives. I intend to load
the polygons into PostGIS for later processing and I need some kind of
key value (filename?) on the polygons. Neither gdal_polygonize nor
gdal_trace_outline have an option for setting an attribute value (the
produced shapefiles have a single integer attribute) to identify the
polygon when they create the shapefile.
So my current plan calls for scripting:
For 300 shapefiles:
Use shp2pgsl to Load shapefile into a PostGIS temp table
(creates a table with a single row),
Use pgsql to do an ALTER table to:
add a IMAGENAME column
update IMAGENAME for the loaded row
copy the row into the final table
delete the temp table
I suppose I could enhance gdal_polygonize (or gdal_trace_outline) to
allow an attribute value, but I'm hoping someone has a simpler, more
elegant way using existing software.
GeoKettle may be an answer, but it has a steep learning curve...
--
Best Regards,
Brent Fraser
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