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I am trying to calculate the area of polygons in a shapefile on QGIS 2.2. My project is in an equal area conic projection with OTF projection activated. When I added a new field called 'AREA' and used the $area function in the field calculator, I got impossibly small numbers. I then switched the CRS on the shapefile from the properties menu from NAD83 to the same US Equal Area Conic and tried to calculate again with the same results. Do I need to make a copy of the shapefile and set to the CRS that way? Or am I doing something else wrong?

  • Is your data extent focused locally to a particular city or state or is it broad spanning multiple states/countries? – artwork21 Dec 7 '16 at 15:42
  • It is focused on the Continental US – Roger Dec 7 '16 at 15:43
  • Did you check your project's settings ("Project" "Project properties..." "General" "Measurements" "Units for area measurement"? The result of $area depends on those settings. – Rudi Uhl Dec 7 '16 at 16:26
  • So after doing that I still have areas that are too small...closer, but still too small. – Roger Dec 7 '16 at 16:43
  • Also, my measurement tool is working, that is how I know the areas are so far off. – Roger Dec 7 '16 at 16:49

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