# MBG_Orientation: ranges from 0-180, instead of 0-360? (ArcGIS, Minimal Bounding Geometry)

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?

• 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 `0°`, or a line drawn at `45°` is the same as a line drawn at `225°`, `135°` at `315°`.

• 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
• @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