I need some help in how to find the long axis of an irregular shaped ellipse using ArcGIS Desktop.

I have found the centroid but don't know how to determine the longest distance.

2 Answers 2


You can use the Minimum Bounding Geometry (Data Management) tool.

Use the 'Convex Hull' option.

This will create several new fields:

MBG_Length will give you the distance between the farthest points (antipodes)

The MBG_APOD points will give you the coordinates of the new antipodal line

Further reference: http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//00170000003q000000

  • It should be noted that the Convex Hull option is only available with an ArcInfo license. If you don't have this license, then this tool may not be sufficient.
    – Fezter
    Commented Jun 15, 2012 at 2:56
  • 2
    This link works for all license levels resources.arcgis.com/gallery/file/geoprocessing/…
    – user681
    Commented Jun 15, 2012 at 12:46

I think at basic license this can be done by using "Rectangle By Area" Command as below is the comparison..


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