Monday, 2 July 2018

shapefile - 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.



Answer




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.


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