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I am currently mapping Lahar flows on Montserrat Island (as many have done before!). I have the Cost Distance analysis below, the circle is the origin and the triangle the destination. With a known destination a Cost Path analysis can easily be performed, however I would like to use the Cost Distance map below to automatically find the destination point, based purely on the the direction of flow from the origin/circle.

I was thinking of using a filter to include only edge cells of the raster, and then find the one with the lowest value, is there a way to do this?

Software: Arc GIS Desktop 10.5

Montserrat

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    What are the components of your cost surface apart from elevation? – FelixIP Feb 18 '17 at 0:37
  • I intend to add in vegetation cover next, but currently the cost surface is solely the DEM of the island. – Sam3000 Feb 18 '17 at 0:39
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    It makes it purely hydrochlorical task. Fill dem, compute flow direction. Create small buffer around lake. Place multiple points on buffer to simulate different outburst locations. Compute cost paths from these points using flow direction as back link, anything as cost – FelixIP Feb 18 '17 at 0:44
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    Fill Dem first to remove sinks – FelixIP Feb 18 '17 at 1:02
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    Let us continue this discussion in chat. – FelixIP Feb 18 '17 at 1:26
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With elevation being single component of cost surface, the task is purely hydrological and can be saved by using relevant Spatial Analyst toolbox.

  • Fill elevation model to remove sinks
  • Compute flow direction
  • Create small buffer around lake and place multiple points on buffer to simulate different outburst locations.
  • Compute cost paths from these points using flow direction as back link, anything as cost.
  • Convert stream to feature (optional)

Input: enter image description here

Output:

enter image description here

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