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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?

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    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
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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
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    @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

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