I'm very new to QGIS. I have been trying to calculate areas of interception and overlapping percentages of different shp polygon layers. I've watched tutorials and have managed to do it well. However, there's an issue that I havn't been able to solve:

For calculating areas in a polygon layer, I go to the field calculator and input "$area", selecting the "real" type. Clicking OK enables edit mode and propperly calculates areas as doubles. However, when I exit edit mode by clicking on the pencil and saving, all areas are rounded to the nearest integer. The datatype of the attribute is also changed to Integer64

My question is why does this happen and how do I stop it?

I'm working with QGIS 2.16(also tested it with 2.14) and for the following example I used the "continents.shp" layer in the world data from the QGIS official tutorial.

Area field creation After exiting edit mode and saving, areas are rounded

1 Answer 1


You have to increase the "Precision" field. Precision represents the number of digits after the decimal separator (official doc), though I have no idea why this field is not taken into account before exiting the edit mode.

  • 1
    That did it. Guess I never checked because it only happened afer saving, as you say. Thank you very much!
    – MV7
    Aug 5, 2016 at 13:40

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