Minimum Bounding Geometry - Length/Width of Polygon(s) - Units

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05-13-2019 06:58 PM
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New Contributor

Hi

I am trying to determine the length and width of polygons in feet. I have learned there is a tool called Minimum Bounding Geometry that seems like the right tool to use to determine this information. The problem is that the MGB_width and MGB_length are coming out as 0.000179 and 0.000195 when I would have expected something closer to 57.36 and 65.17. I have tried re-Projecting the layer but it does not appear to make a difference. Any help related to what I am doing wrong and how to correct the issue would be greatly appreciated.

Thanks

Shawn

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MVP Esteemed Contributor

Use the projected file.

Open a new dataframe (arcmap) / map (ArcGIS Pro) with NO basemaps or any other data in it.

The first layer that is added sets the coordinate system of the mapping framework.  I want to make sure that the dataframe/map have the exact same coordinate system as the projected layer.  Check

Minimum Bounding Geometry—Data Management toolbox | ArcGIS Desktop 

way down at the bottom of the link, you will notice that the tool support an output coordinate system environment parameter.

Check the tool's Environment settings prior to running the tool to make sure that the output coordinate system is indeed set to the projected LCC.

I suspect that things are being projected-on-the-fly to a geographic coordinate system because of the dataframe/map setting or the environment parameter in the tool's settings

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MVP Esteemed Contributor

Your middle image of the layer shows that the coordinate system is in decimal degrees.

Did you use the Project tool to get a new file in the projected coordinate system that matches the map/dataframe?

If you project the layer (not define projection) you will get coordinates in planar units.  If your coordinate system uses feet, then your bounding units will also be in feet

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New Contributor

Hi Dan

Thanks for helping. I have tried both projecting and not projecting the starting layer using a Projected Coordinate system of NAD 1983 (North Carolina using a linear unit of feet). All of my tests appear to end up with a Geographic Coordinate System of GCS_WGS_1984 with the Minimum Bounding Geometry tool run regardless of the starting layer's projection. Thoughts? 

Initial Starting/Input Layer:

Starting Layer Projected

MBG Result:

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MVP Esteemed Contributor

Use the projected file.

Open a new dataframe (arcmap) / map (ArcGIS Pro) with NO basemaps or any other data in it.

The first layer that is added sets the coordinate system of the mapping framework.  I want to make sure that the dataframe/map have the exact same coordinate system as the projected layer.  Check

Minimum Bounding Geometry—Data Management toolbox | ArcGIS Desktop 

way down at the bottom of the link, you will notice that the tool support an output coordinate system environment parameter.

Check the tool's Environment settings prior to running the tool to make sure that the output coordinate system is indeed set to the projected LCC.

I suspect that things are being projected-on-the-fly to a geographic coordinate system because of the dataframe/map setting or the environment parameter in the tool's settings

View solution in original post

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New Contributor

Thanks. It appears to have been the environment setting.

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