Finer Scale Convex Hull

[DarrenWiens2]

Is there a way to shorten the search distance for creating a minimum convex hull polygon from line features? Basically, I want a polygon surrounding the line features in picture 1, but the best I can do so far is what's in picture 2. It would be nice if I could say, "only look this far ahead and make a polygon edge from those lines it has encountered".

[DanPatterson_Retired]

What you are describing is a variant of the concave hull.  There is one implementation here:
http://resources.arcgis.com/gallery/file/geoprocessing/details?entryID=AA23C5C6-1422-2418-8811-13652...
There are other ways of generating concave hulls, but this may be a start.

[Anonymous User]

Original User: jscheirer

Like a concave hull?

[DarrenWiens2]

Yes, thank you. I ran the tool, and it looks like that would be a good starting point (it would need some work to clean up). I ended up finding a boundary polygon afterall, but it's nice to know this exists.

[Anonymous User]

Original User: bruce_harold

Darren

Please also see the attached tool, with thanks to the University of Minho in Portugal for the idea.
It requires point input data (use Feature Vertices to Point GP tool to make this) and is not as fast as the other referenced tool, but may be closer to what you need.

Regards

[DanLee]

If you are using ArcGIS 10, you can do the following:
- Run the Feature Vertices To Points with the ALL option to convert your lines into points.
- Run the Aggregate Points Tool to combine the points into a polygon with an aggregation distance you specify.
- If you get undesired holes in the polygon, run Eliminate Polygon Part tool to remove them.

Hope this is a good alternative for you.

Thanks.

[Anonymous User]

Original User: dkwiens

Thanks all. That's exactly what I was looking for Dan. I should probably explore the cartography toolbox a bit more.

[DanLee]

Really glad to hear!  🙂

[DanPatterson_Retired]

I am sure all of the ArcInfo license holders are ecstatic...but don't get too excited for the ArcView of ArcEditor holders...(please ESRI...qualify license levels)