I'm trying to understand the concept of the Orientation of the Minimal Bounding Geometry: Minimum Bounding Geometry (Data Management toolbox, ArcGIS Desktop 10.1).

I run the tool Minimal Bounding geometry -> Rectangle_by_width -> "Add geometry characteristics as attributes to output". For every polygon I've got back: MBG_Width, MBG_Length, MBG_Orientation. As it is written in the tool description: "the orientation angles are in decimal degrees clockwise from north". My resulting angles range, however, from 0-180, not to 360, as I would expect.

How can I interpret my results? I doubt to have only eastern orientations in my data. Is there any simple drawing explaining how the MBG_Orientation is calculated in ArcGIS, i.e. from which point, to which direction? Or why the resulting orientation is from 0-180?

  • 2
    0...180 is enough in this case, because arcgis has no idea of true 'direction for shape(s)' if such thing even exist – FelixIP May 9 '17 at 18:04

Once the angle hits 180/vertical it starts again at 0, as there is no known direction.

To illustrate, I have drawn a line at 45° and another at 315°, but when I run the Minimum Bounding Geometry it returns a value of 135° for the second line.

This is because when there is no defined direction, 180° is the same as , or a line drawn at 45° is the same as a line drawn at 225°, 135° at 315°.

enter image description here

  • WoW! please, is there a way how to measure the relative orientation of one shapefile to another? i.e. beetle infestation from one year to another - do they tent to appear in specific orientation from the previous infestations? I thought to solve it by MBG, but this won't be true anymore... – maycca May 9 '17 at 18:34
  • 1
    @maycca You should ask that as a new question, include these specific details. Show that you tried with MBG (link back to this post as reference) which didn't work, so asking how to do it. – Midavalo May 9 '17 at 18:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.