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I am investigating methods to perform a simple least cost path analysis with gdal. By simple, I mean using the slope of a dem as the only cost factor.

I would prefer to do using the python or .net bindings, but will take anything. Can anyone suggest any good tutorials or the like?

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For analytical questions, perhaps better use a GIS rather than a data format abstraction library... – markusN Jul 1 '12 at 8:12
Out of curiosity, what is the application? It is difficult to think of anything for which the DEM's slope would be a realistic proxy for the cost of travel. Are you sure this is what you need? It would be a pity if, after going to the effort of writing this code, you discovered it did not actually solve your problem! – whuber♦ Jul 1 '12 at 17:42
Slope could be useful as a travel cost if you're modelling a gravity-dependent dispersal model of some sort, though I'd expect some other factors too rather than just slope. – MappaGnosis Jul 2 '12 at 8:45
Also, slope usually shows the maximum slope at each cell, even if the route is not travelling directly downhill or uphill. – Matthew Snape Jul 25 '12 at 20:05

1 Answer

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You can use the A* search algorithm using slope as the cost between generated nodes. To see a quick visualization of what that looks like:

A Star Animated

See A* Search Algorithm (Wiki) and Python A* Search Algorithm (SO)

to understand A*.

For a slope map there are options out there - Here is one.

With a slope map (raster) you can get cost values out of it with GDAL.

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