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I am relatively new to ArcGIS.

I am looking to find the least cost path between a number of points in a landscape (eastern Sicily) that avoids rivers (obviously a Roman cart would not plough through a river). I have DEMs for the elevation and ran the analysis for the slope, and I had a shapefile for the rivers which I used to also create a feature; I've used conversion tools with this to create a raster for the rivers too. I'm just not sure where to go from here!

I'm using ArcGIS 10 on Windows 7.

I do know how to use the cost distance, back link, and cost past tools to find the least cost path; my problem is getting the rivers incorporated into this.

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You should integrate the rivers as an extraordinarily large cost value, several many orders of magnitude greater, that will force the algorithm to never include rivers in the calculations. Rasterize your rivers the same spatial resolution and registration (snap raster) as the cost surface - if you haven't already. Run a map algebra/raster calculator in a way that combines the two, and wherever the rivers are, add said big value to cost surface. (you can use conditionals, multiplication [beware the of zeros] or a simple addition of the river values if they're are already high).

There might be more advanced ways to execute cost distance with barriers, but I think this method is simpler to handle.

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  • Should I do that when I reclassify the result of using the Euclidean Distance tool with the raster I get when I use the Polyline to Shapefile tool? Let me show my path in an easier way: river shapefile -> river feature -> polyline to raster (using river feature) -> river raster input into Euclidean Distance tool -> result of this into Reclassify tool where I adjust the cost value to be very high -> into raster calculator with slope? I'm sorry, I am incredibly new at this! Thank you for your comment though!
    – lbc15
    Commented Jan 20, 2015 at 22:24
  • I actually had a friend help me figure this out today - so this has been solved. Thank you!
    – lbc15
    Commented Jan 21, 2015 at 13:25

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