Curious Polygon Output from Cost Distance Tool

[TimSmith4]

I am using the cost distance tool to map out helicopter response times with constraints (mountain passes, geographic boundaries, etc).  I have a uniform cost raster where the value of each pixel is equal to the amount of time it takes the helicopter to overfly the pixel.  The Cost Distance Tool adds up all these bits of time to produce a map of response times, but where I would expect the map to be circular in shape it instead is an 8-sided polygon.  My question...

Is there a way to make Cost Distance Output maps circular, or are polygon outputs the result of the underlying algorithm?

[DanPatterson_Retired]

if the cost surface is uniform, just run a Euclidean Distance (then reclass) depending upon preference.  I think what you are seeing is an artifact of the cost tool working on a cumulative 8 cell neighbourhood

[TimSmith4]

Great thanks!

[DarrenWiens2 · Accepted solution]

See this discussion for a nice explanation of exactly your problem (in the end, use Euclidean Distance, as mentioned above):

Circular vs. Octagonal Cost Distance

[Anonymous User]

Hi Tim

In 10.7.1 arcmap or later, you should be able to use the new 'barriers' parameter in the Euclidean distance toolset. Please see this blog post.

In pro 2.5 or later you can use that or the new Distance Accumulation tool (for more involved cost surfaces).

Regards,

-Jim TenBrink

spatial analyst team