Assigning polygon-to-polygon orientation angles to polygons with shared geometry.

[AlexBoone]

Using the "Generate Near Table" tool it is possible to determine the "NEAR_ANGLE" between polygons.  However this only works if the polygons do not share borders.

In the image attached, I'd like to indicate the orientation ("NEAR_ANGLE") of the polygons surrounding polygon 9, relative to polygon 9.  I.E.12 is north, 10 is east etc.

Is this possible?

Thanks!

-Alex

[DanPatterson_Retired]

for those simple cases, produce the centroids of the polygons and perform the analysis using the centroids, then join the results back to the polygon... for those simple cases...

[AlexBoone]

Hi Dan,

Unfortunately my actual polygons are more complex than my example.  The centroid method won't work especially with long, linear polygons, see #7:

I would like the table to indicate that #7 is west of #3, using the centroid method indicates that it is south of #3.

Thanks.

[DanPatterson_Retired · Accepted solution]

If its not something it's something else   so some other options

That is part of a sort, is is indeed correct, 7 is south of 3, then you sort the centroids to get the West to east direction.  

Others

• do an internal buffer (-ve buffer) by the exact correct amount that it works 
• lexicographically sort your polygons and assign an EW, NS order to the centroids (more formal than the method which I suggested that works
• create a medial axis from the polygons and use those
• select the ones that have to be done manually and do those.

Nothing is going to work for everything I suspect

[AlexBoone]

Dammit, why can't everything have a simple, one-size-fits-all solution!

Thanks again for your help Dan, I'll look into those options.

-Alex

[VinceAngelo]

You can compute the intersection of the neighboring shapes (which will generate a line or point, or a line and a point) and compare the envelope of the relationship geometry with that of the reference shape, which would let you discern intercardinal directions (N/NE/E/SE/S/SW/W/NW) or even "Within".

- V

[DanPatterson_Retired]

the same result as a lexicographic sort of the centroids, then a point to point  line creation,selecting the shortest .

A minimum spanning tree of the centroids starting at the west most centroid will produce a good result also if the polygons are elongated in the NS direction compared to the EW.... the list goes on, but manually selecting and ordering them at a rate of 1 polygon per second will give one an idea how long it will take the mis-behaving one to get done relative to the easy ones.