topic Wind direction cross Polygon_max distance in ArcGIS Spatial Analyst Questions

Wind direction cross Polygon_max distance

MarziehForoutan — Wed, 22 Nov 2017 18:03:00 GMT

Hi All,

I have a wind direction and many polygons as a shape file and I want to measure the longest distance that this wind can travel over the polygon (see attached image for clarification). Since I have lots of polygons its pretty hard to measure it individually. Any idea is really appreciated.

Thanks in advance

Re: Wind direction cross Polygon_max distance

DanPatterson_Retired — Wed, 22 Nov 2017 18:12:08 GMT

some implementations of 'wind fetch' can be found published elsewhere

http://www.spatialecology.com/gme/geompolygonfetch.htm

similar implementations can be accomplished using the spatial analyst extension approximately using

Zonal Geometry and/or Zonal Geometry as Table If you want an exact solution, the coding will be required, and given the market for such things is meagre, then you would have to specify your constraints specifically to see if the problem were interesting enough to warrant any investment in time coding a solution

Re: Wind direction cross Polygon_max distance

curtvprice — Sat, 25 Nov 2017 19:50:46 GMT

I can imagine a workflow:

1. create a line of cells away from your zones, perpendicular to the wind direction, each cell with a unique value

2. Run the Euclidean Allocation tool, include the parameter to create a eucdist raster

3. Run Combine tool of rasterized zones + euclidean allocation zones

4. Summary Statistics on the combine result table to identify max number of cells (longest stripe) in each zone

5. Select these zones and run Zonal Statistics As Table against the eucdist raster to get the range (max-min) of euclidean distances in that zone, that's your fetch length.

Map algebra really is pretty cool.