topic Re: Make a minimum bound ellipse? in Geoprocessing Questions

Make a minimum bound ellipse?

LauraDugan — Thu, 16 Aug 2012 17:57:10 GMT

I am trying to make an ellipse around a set of points, and I essentially want to do what the 'Minimum Bounding Geometry' tool does, but I want it to make the smallest ellipse around my points rather than a rectangle, circle or envelope. I am ultimately trying to show the regions of globe that have been studied more than others by plotting the coordinates for individual study areas. This is for visualization only (not for quantitative analysis), so I want to make it look nice and consistent. I think using ellipses around the study areas will be the most visually appealing. I just can't figure out how to make them. Also, I don't want to use the draw function, because I would like to be able to play with merge and intersect and some things later to show which areas have been most studied i.e. I ultimately want shapefiles.

Thanks!
Laura

Re: Make a minimum bound ellipse?

JochenManegold — Fri, 17 Aug 2012 13:28:26 GMT

Hi Laura

the spatial statistics tool "Directional Distribution (Standard Deviational Ellipse)" may help

Jochen

Re: Make a minimum bound ellipse?

DanLee — Fri, 17 Aug 2012 17:29:48 GMT

Laura,

If you would like to promote the ellipse option for Minimum Bounding Geometry tool, you can post the idea at the Ideas site, so that other people can vote for it.
http://ideas.arcgis.com/ideaHome?c=09a300000004xET

Thanks.

Re: Make a minimum bound ellipse?

LauraDugan — Sat, 18 Aug 2012 22:56:37 GMT

Thanks Jochen!! I think this will work for my purposes. I appreciate it!

Dan - I am submitting the idea now. Thanks for the suggestion.

Laura

Re: Make a minimum bound ellipse?

DanLee — Sat, 18 Aug 2012 23:19:24 GMT

Thanks, Laura.

I was hesitating to suggest the Standard Deviational Ellipse because it may not be bounding your data. Just want to let you know.

Re: Make a minimum bound ellipse?

DanPatterson_Retired — Sun, 19 Aug 2012 09:14:57 GMT

A cautionary note, a minimum area bounding ellipse (MABE) is only going to make sense if you are using planar (aka projected) coordinates. If you have a projected point shapefile with the points grouped by some attribute so one can differentiate groupings of points then email a zip file to Dan_Patterson @ carleton.ca since I have a toolbox which I havent' posted, that calculates the MABE. I can do a run on it so you get a sense of how the MABE compares to the standard deviational ellipse.

Re: Make a minimum bound ellipse?

BruceHarold — Mon, 20 Aug 2012 14:04:16 GMT

...anybody mention Tissot Circles around lat/long coordinates that will look like ellipses when projected? 🙂

Regards