Cost Path problem: paths are just origin pixels

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05-20-2012 09:02 PM
PaulMaier
New Contributor
Hello,

I am trying to create a basic set of cost paths from a FC of points to the same set of points. The friction raster is simply slope, derived from a 10m DEM. The slope has been reclassified so that values range from 1-10 (e.g. 30-39% slope is value 3). I use Cost Distance (spatial analyst: distance) to create a cost distance raster and backlink, then use these outputs to create cost paths.

No matter what I do, the cost path output is just single pixels, centered on the original points. The remaining extent of the cost path raster is coded as NoData. WHY?? I have tried tweaking all sorts of parameters, simplifying the number of points (from original number 213 to just 5), the slope raster (reclassifying to fewer categories), but inevitably the output is the same. The projections are consistent - everything is in NAD83 11N. So what is going on?

A couple of clues. The cost distance output is taking values of 1-10 and creating enormous values (0-26,000); perhaps this is making ANY path too costly? This seems unlikely. Another clue: there is a cost path tool in the user-created Landscape Genetics toolbox, and running this tool with the points and the reclassed slope raster incurs an error:

<class 'arcgisscripting.ExecuteError'>: Failed to execute. Parameters are not valid.
ERROR 000732: Input Data Element: Dataset lcpPoints.shp does not exist or is not supported
Failed to execute (Delete).

OR

Failed to set analysis window.

Any ideas would be very helpful!
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JeffreySwain
Esri Regular Contributor
Try creating the cost distance with just one of the inputs and then when determining the Cost Path use the other ones.  The reason you are getting the single cell paths is that you have the same inputs for each, so there is no 'path'.  You asked the algorithm to find the quickest path from these locations to themselves.  Try to create a cost path for one of the points and then try using the other points as the inputs in the Cost Path tool.
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