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Cost Path Problem When Encountering Small Stream Line Features

Question asked by mbd63031 on May 5, 2017
Latest reply on May 5, 2017 by mbd63031

Hello all,

 

I think I've discovered an issue with a method I'm using. Hopefully someone can help or at least point me in the correct direction.

 

I'm trying to use both slope and water accumulation as variables to determine where a historic trail could have traveled. I'm using a least cost analysis to do so by creating my own scale within each variable by reclassing results. These are then combined using weighted overlay to give me one raster set depicting where the easiest and most difficult areas to travel would be.

 

My problem comes in when using the cost path tool. It will draw the easiest path, or the past of least resistance, but the problem regards small wash line features. Although the program marks these as areas where water is more likely to accumulate (thus areas they wouldn't want to travel), when cost path runs it thinks it can go to the cell next to the stream and then cross diagonally, completely avoiding the line feature.

 

I've attached a picture to better describe what I'm talking about. The red line is the cost path drawing, the costs in the area are higher with darker blues, lower with lighter blues (or light purples). If you notice, at several points the path diagonally jumps across a stream when the stream is traveling diagonally as well. Checking the values of these cells, it certainly doesn't seem to be accounting for the higher valued cells around it.

 

Anyone have an idea how to fix this? Should I try finding a way to restrict movement just to up, down, left, and right? I'm at a loss at this moment, as I'm pretty new to using the program.

 

Help is appreciated!

 

Matt

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