I have uploaded a shapefile and I am simply trying to calculate some simple areas of provinces (and I know their areas from Wikipedia). My map is from Zimbabwe, and I have saved the project, reprojected all layers, and saved everything as WGS 84 / UTM Zone 36S. The units are all in metres.

When I use $AREA function in field calculator, the areas come around very very small. I expect areas in order the thousands of square kilometers, but I get numbers like 3m2.

Why are my results so far out?

Edit: I've added images of the property settings

Project properties

Layer properties

  • 1
    Because your calculations are done using a geographic CRS instead of a projected one. Make sure the layer is actually saved using the correct UTM zone.
    – Erik
    May 13 '19 at 18:30
  • Sorry, but I thought saving everything as WGS 84/UTM Zone 36S would be a projected CRS. Is this not a UTM CRS? May 14 '19 at 7:35

Based on your screenshots it seems you did not reproject layer but defined (wrong) layer CRS. To reproject layer if actually needed, you need to export layer it and on export define desired CRS.

Check 'General Project Settings' what units are set for area measurments:

enter image description here

And Settings menu, Options:

enter image description here

  • I can't see the map tools option in QGIS (I'm using QGIS 3.6 - do I need an additional plugin?) but everything under general says meters, rather than degrees, and the area is measured in square metres. What could be going wrong? May 14 '19 at 7:39
  • @MichaelHammond it can be found under Settings > Options
    – AWGIS
    May 14 '19 at 7:48
  • Thanks. Still, everything seems to be in metres, in a UTM projection, etc. I can't see why I'm getting funny units May 14 '19 at 7:53
  • Try ctrl+shift+J what values you get. Where did you get shapefile. Is it possible its not in actual scale? Try loading OpenStreetMap to make sure. You can use Open Layers plugin for that..
    – Mat
    May 14 '19 at 7:54
  • 3
    Maybe you didnt actualy reproject but just defined layer projection? If you changeed CRS under layer properties you only defined (wrong) projection of layer data not reproject. You should leave data as is and reproject only by changing project CRS if needed. Or Export layer and on export change to desired projection.
    – Mat
    May 14 '19 at 8:14

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