Code to calculate elevation profile along line from a DEM

Question

Given a DEM (Digital Elevation Model) say in and a line (x1,y1) --> (x2,y2) (paired coordinates (x,y)), how can one calculate the elevation profile or cross-section projected on that line ?

I am looking for open source code that i can use in my project or pseudo-code that I can use as a guide.

Answer 1

The GRASS command r.profile performs this (documentation, source) and should provide a good basis for implementing a cross section, and is available under the GPL.

Answer 2

Maybe QGIS "Profile" plugin source code can be a start.

Answer 3

Here screenshots for GRASS:

Answer 4

You can go much further by combining DEM and raster colors, using GRASS with R (see Raster profile along arbitrary line segments, or http://www.portailsig.org/content/grass-gis-et-r-superposition-des-couleurs-d-un-raster-quelconque-sur-un-profil-topographique and with Python (Python: utilisation des couches vectorielles et matricielles dans une perspective géologique, sans logiciel SIG , in french, but the scripts are universal...)

with Elevation colors (GRASS GIS and R):

With colors of a Geological Map (Python with GRASS raster)

And using the Python script in the Python console of QGIS: