Finding nearest wind data point for given location

Question

Hi,

I am using ArcGIS Pro to work out which areas of terrain are exposed to prevailing winds. I have a 20 m DEM (with which I have created an aspect raster) but my wind data (in degrees, direction only) is approximately 2 km resolution and in netcdf format. I have successfully added the netcdf wind data to my map and converted it to point data. (which I think is the correct step). I need to find the wind direction at every DEM point, but rather than interpolate the wind data to the high res DEM, I want to know the wind direction at the nearest wind data point to any given point.

Is there a straightforward way to do this?

danretired · Answer

Did you look at the suggestion then?

RachelBadlan · Answer

The reason I am lookig at wind and topography is to identify areas of terrain that have increased fire risk given certain conditions. The wind data is gridded ad we really want to identify the general direction of flow in a given area (i.e. to get an idea of blocking due to terrain).  The wind doesn't have to be exact or high resolution, as the algorithm we use to identify areas of risk has a fairly large uncertainty built in and will allow fairly large variations in very local wind conditions. We just want to be able to assume the given wind direction at any wind data point to be associated with the terrain around it. Therefore given a regular grid of wind points ( 2km x 2 km - delta x and delta y), a 2 km x 2 km area of the DEM would be associated with each gridpoint (with the wind data in the centre of that square area).

Hopefully this makes sense!

danretired · Answer

It almost sounds like

Distance Allocation (Spatial Analyst)—ArcGIS Pro | Documentation

but what variant you use and whether it is appropriate would depend on your data.

What do you think the interplay is between your topography and wind direction? and where was wind direction being measured?  Fuzzy questions perhaps, but you want to be careful about allocating anything anywhere unless there is a sound reason