author: Jeff Hollister date: 11/14/13
Based on my understanding of the current NSink tool, the information we would like out of it is the following:
Weighted FlowLength - FlowLength should be close. Just need to figure out how the weighting works.
Cost Path: Inputs are grid with source and destination. Plus a backlink grid. The backlink grid is simply flow direction from the elevation. Cost surface is a constant. I used the “Best_Single” path type. It should work (haven't tested this) for multiple end points (i.e as in coastal watersheds) and would pick the shortest one.
Only two geoprocessing services required. One, get the starting point and two, calculate the flow path with Cost Path.
So, for instance:
Here's an image of starting elevation:
Next a possible starting point on the landscape:
And the resulting flow path from that point:
A second starting point:
And a second flow path:
Take flow path, calculate Euclidean distance from that flow path, select cells greater than buffer distance and turn to NA. Mask out landcover. Count cells of each class, multiply by 900.
Need to think more about this, but it is some combination of Flow Accumulation and sinks.