[gdal-dev] Best way to test wheter point is contained in Polygon

Jose Gomez-Dans jgomezdans at gmail.com
Mon Sep 22 10:35:08 EDT 2008

I have a raster file and a vector file. I want to assign to each pixel in my
raster size a value derived from the vector file (which are polygons). To do
this, I want to test that the centroid of my pixel lies within a given
polygon. In the past, I have done this gdal_rasterize-ing the polygon file,
and going through numpy arrays. It is a bit cumbersome, and the
rasterization is not really needed with OGR. However, it seems that if my
pixel centroid is (x,y), I will need to go through all features in my layer,
extract the geometry and do a Contains() test for my (x,y) point. I can cut
the number of iterations (I guess, not tried) by using a SpatialFilter on my
vector layer, so only one (ish) geometry is returned, so I would only need
to do one Contains test (I do have a _lot_ of polygons in this file)

Is there some other (better) way of doing this? I'm using the python ogr


Centre for Terrestrial Carbon Dynamics
Department of Geography, University College London
Gower Street, London WC1E 6BT, UK
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/gdal-dev/attachments/20080922/d10f0ef6/attachment.html

More information about the gdal-dev mailing list