[Freegis-list] Rasters, Vectors and spatial databases

[Jose Gomez-Dans]

Hi Frank,
Thank you very much for your prompt reply. It is really very appreciated!
> OGR, the vector side of GDAL/OGR can support Oracle Spatial,
> so in if you build it carefully to include Oracle support you could use
> OGR to extract the polygon(s) from Oracle.  Either at the commandline
> with ogr2ogr, using the C++ API or perhaps from Python.

OK, this looks like a doable possibility. There's also a C interface
to OGR, is there not?
 
> I'm not sure what you have been using to rasterize he polygons so
> far, but I do know of folks doing this sort of thing with MapServer.
> The whole process could also be automated in GRASS which includes
> GDAL raster access and OGR vector access as well as good polygon
> rasterization for masking, and sophisticated sorts of raster analysis.
> You might need to be somewhat handy with shell scripting to automate
> it in GRASS.

I think my colleagues working ont he GIS side have used some
propietary software, but rasterisation is problematic for a number of
reasons, and needs a fair bit of user input. Ideally, I would like to
have the polygon edges, and select the pixel values which lie within
said polygon. I have coded similar algorithms in the past, but have
found that my implementation was *ahem* not optimal :), and I was
thinking that there ought to be a better implementation. OSSIM has an
implementation  (see
<http://www.remotesensing.org/doxygen/ossim/classossimPolygon.html#a27>),
so this could be re-implemented (given it is free software) for our
purposes. I was actually wondering whether GDAL and OGR are connected
somehow.

Again, thank you for your comments,
José