Hello all,

I've noticed that there is a Minimum Bounding Geometry tool now. How might I use this tool (or related tool within ArcGIS) to create a 95% Minimum Convex Polygon. It would appear that the before mentioned tool is performing a 100% MCP.

Thanks for your help.

I've noticed that there is a Minimum Bounding Geometry tool now. How might I use this tool (or related tool within ArcGIS) to create a 95% Minimum Convex Polygon. It would appear that the before mentioned tool is performing a 100% MCP.

Thanks for your help.

some issues... creating the convex hull (CH) (aka convex polygon) and removing the hull points and re-doing the analysis will fail in almost all cases ... as will buffering negatively by 5% of the area not fairly represent your analysis, so in short could you provide some visuals or some description which would account for the general situations ie your clustering consists of 4 points, 5 points with one outlier etc etc. it may be the clustering algorithm that you are interested in rather than the CH

I am in the same situation as the original poster in that I too would like to construct 95% minimum convex polygons.

Mr. Patterson, I think you may be right in that this may be a clustering algorithm issue rather than the convex hull tool itself. The only example I can provide that better describes our question is this:

I have a distribution of animal movement points, i.e. lat/long (WGS 84), and I have just used the Minimum Bounding Geometry to construct a convex hull that encapsulates all of my points (see attached document). However, it is apparent that there are areas within my polygon that contain no points (empty) or are not near any other points, i.e. outliers. Essentially, this polygon represents 100% of my data points--this is what I believe the original poster meant by a 100% MCP. The downside of this method is that it produces a "home range", i.e. convex hull, that incorporates areas never used by the animals. Therefore, as a means to alleviate this downside, researchers disregard or remove the top 5% of the data points in hopes of reducing the impact of outliers or large data points. The new "home range," then, is 95% of the original 100%.

Is there a way to do this in ArcGIS?

Thanks in advance!

## Attachments

Does that help?

You will have to search for concave hull

http://resources.arcgis.com/gallery/file/geoprocessing

Thanks for the prompt responses and redirection. I'll give both of your suggestions a look and get back. Again, thanks!

Thanks, Josh