Calculating polygon areas in QGIS?

  • How do I calculate areas of an area shapefile in square meters or in acres (ha)?

    I didn't find that functionality in the vector tools.

  • Stev_k

    Stev_k Correct answer

    9 years ago

    Make the layer editable, then use the field calculator (Layer>Open attribute table>Field Calculator/Ctrl+I or right click shapefile>Open attribute table>Field Calculator/Ctrl+I). There is an operator "$area" that will calculate the area of each row in the table. All units will be calculated in the units of the projection, so you probably want to project it to a projection that uses feet or metres before doing that, rather than lat/lon.

    In current versions of QGIS if your data is in a Geographic CRS you can use the function transform() to project the geometries to a projected system (Preferably an equal area one) without the need to duplicate your data. In the Field calculator, something like this should work: area($geometry, 'EPSG:4326','EPSG:3763')

    @AlexandreNeto: Do you mean `area(transform($geometry, 'EPSG:4326','EPSG:3763'))`?

    @smacdonald yes, my mistake.

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Content dated before 6/26/2020 9:53 AM

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