[Gdal-dev] Getting started with raster processing with GDAL/OGR

[Roger André]

Hi Ivan and Mathew,

Thank you both for your responses.  Ivan, I appreciate the simple
description of how to assign values to raster cells.  Mathew, your
script is exactly what a colleague of mine needs to complete a project
he's working on, and I believe I can follow what it does well enough
to understand how I can adapt it for making my heat maps.  Also, I
wanted to thank you for the other examples of code that you've posted
on PerryGeo.  The "Tissot Indicatrix" page was what whetted my
appetite initially to learn how to use OGR from within Python to do my
own GIS processing.

Thanks again,

Roger
--

On 9/9/07, Matthew Perry <perrygeo at gmail.com> wrote:
> Roger,
>
> On 9/9/07, Roger André <randre at gmail.com> wrote:
> > I'd like to start making some "heat maps" in raster format using the
> > Python API to GDAL/OGR.  In a nutshell, what I'd like to do is overlay
> > an empty raster grid (no intentional reference to the ESRI GRID
> > intended) over various point data sets and assign the grid cells
> > values based on the point data attributes.
>
>
>  I've got a  "point density" script that you could take a look at. It
> is pretty basic; given a raster extent and cell size, loops through
> each cell, performs a spatial filter on the point dataset and writes
> out the number of points encountered within that raster cell.
>
> http://perrygeo.googlecode.com/svn/trunk/gis-bin/point_density.py
>
> Note: it uses the "old" python bindings (with Numeric instead of
> numpy) and I haven't tested it with the next-gen bindings.
>
> Hopefully this will be of some use to you. Best of luck.
>
> --
> Matthew T. Perry
> http://www.perrygeo.net
>
> "You never change things by fighting the existing reality.
> To change something, build a new model that makes
> the existing model obsolete" - R. Buckminster Fuller
>