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How do you apply a unidirectional buffer?

September 15 2010 | 0 comments
Categories: Map Data

I am trying to represent the spread of vehicular pollution from major roads. So basically, I have identified the busiest roads and the prevailing wind direction and now want to buffer the roads in the direction the wind blows to simulate multi-rings of decreasing pollution distribution from the source i.e. the roads.

I have used the multi-buffer tool in ArcMap 9.3 but can't get it to prioritise a specific direction for the buffer?

Any assistance would be greatly appreciated.

Mapping Center Answer:

I took a different approach to this using raster processing and then ultimately overlaying the results with the buffers.  I am attaching a zip file with the data and results so you can see what I did.  First I used the Euclidean Direction tool to create a surface that represents the directions away from the points that I used as inputs.  (This will also work with lines or polygons as inputs.)  Then I reclassified the surface to create a raster that had values for North, Northeast, East, etc... (You can make this as detailed as you want so you could make it simple like N,S,E,W or detailed like N,NNE,NE,ENE, etc...) Then I converted the reclassified raster to polygon.  Then I used Identity to overlay the direction polygon layer with the buffers. The last step would be to select only those poolys that you want based on the direction(s) you are intersted in. You could do this using Select by Attributes and then exporting the selected features in the layer.

In the output, I used the symbology described in the Aspect-Slope Map blog entry.

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