Mitered corners on overlapping buffers?

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03-23-2012 03:46 PM
TrishRice
Occasional Contributor III
I can't find this question addressed anywhere.  Is there a way to create mitered corners where buffers would normally overlap?  Instead of the overlapping ovals that result from a Round end type or the rectangles that result from a Flat end type, I want to end up with polygons that come to a point like picture frame corners.

The purpose is to make something kind of similar to a Thiessen polygon, where you can tell at a glance what area belongs to each feature.  But the area would surround polylines instead of points.  Thanks.
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markdenil
Regular Contributor II
Well, if you convert the polygon verticies to points (maybe densifying the verticies first), you could create Thiessen polygons on them and then dissolve the new polygons on the original polygon ID that was carried over to the points and then the Thiessen polygons.

Then, intersect the dissolved Thiessen polygons with the buffers.

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ChrisSnyder
Regular Contributor III
How about the euclidean alocation tool? (Spatial Analyst extension required)

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z0000001m000000.htm

Maybe some form of the buffer tool output intersected with vectorized euclidean alocation output?
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markdenil
Regular Contributor II
Well, if you convert the polygon verticies to points (maybe densifying the verticies first), you could create Thiessen polygons on them and then dissolve the new polygons on the original polygon ID that was carried over to the points and then the Thiessen polygons.

Then, intersect the dissolved Thiessen polygons with the buffers.
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TrishRice
Occasional Contributor III
csny490, thanks for the link but unfortunately I don't have Spatial Analyst.

Thank you too mdenil.  It's a great idea that one would expect to work, I should've mentioned that I tried it and had problems.

Here's what I did.  I'm working with street segments that are split at each intersection.  I turned all the vertices into points.  I ran thiessen polygons for those points, then merged the polygons together based on the original line segment ID.  That's when I discovered the problem: what happens when turning those polylines into points is that you get a point in the middle of the intersection that belongs to not just one line, but several lines.  The thiessen polygon tool creates a polygon around that point the same as any other.  But the resulting polygon describes an area that is closer to the intersection than to any other vertex of those intersecting lines.  Which is not what I want.

Maybe densifying will make a difference.  I haven't heard of that tool before.  If I'm imagining it correctly, densify will create extra vertices along the line at a specified interval?  That could be useful to shrink those useless polygons down to a tiny size.
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TrishRice
Occasional Contributor III
All right, densify did the trick!  Thank you so much mdenil for suggesting it.  The attached screencap is the result when I densified the lines to 3 ft distance.  This will work well for my needs, thanks again!
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