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I'm trying to create a shapefile of fields, drawing polygons around each field, and having the acreage calculated in the attribute table. I believe I have the projections correct. It's not coming up with accurate figures. How do I correct this?

Thank you!

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2 Answers

The units are based on your projection, either meters, feet, or degrees. If you're calculating area with a projected dataset you're either getting square meters or square feet, you'll need to apply the appropriate conversion factor to get acres.

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Thank you. I added in the conversion factor and got a much better answer! I appreciate your help. –  Vicki Mar 11 '13 at 20:21
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The units are associated to the project you create the shapefile as. If you set it as a UTM projection, you will be working in meters. If you use a Lat/Long projection, you will be working in degrees. If you are using a State Plane projection, you will be working in feet. Within the attribute table when you are calculating you can always perform a conversion on the calculated area.

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State Plane can be meters or feet. –  Dan C Mar 11 '13 at 17:59
    
Thank you for your quick response. This seems to work. I think the layers I was working was in a different projection. –  Vicki Mar 11 '13 at 20:23
    
I'm glad everything worked for you –  Ryan Garnett Mar 11 '13 at 20:42
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