I tried showing $area of polygons in QGIS, and it always showed planimetric square degrees instead of metric units. No matter what I set in project general settings, the value remained the same.

QGIS version is 3.4.3, layer CRS is 4326, and I tried different CRS in the project, which made no difference.

I calculated a new field with the formula: $area / 10000 (to get hectares, which is more readable). And looking it up in Wikipedia, the city area is close to that and is rather correct.

So, you can get $area but have to use field calculator. Is there a workaround to make $<function> work correctly in labels?

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Following suggestions by @MAP: the derived tab in object properties is always correct...

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...But the reason I'm asking is that the function description promises to work this way too:

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...while simple area(geometry) is always planimetric.

  • Which CRS (EPSG) uses your QGIS project? (as shown down right in the status bar)
    – MartinMap
    Jan 1, 2019 at 21:18
  • @MAP: it's 3857. Changing it also does not make any difference.
    – culebrón
    Jan 1, 2019 at 21:27
  • Try: Compare the results in the "derived" tab in the Identify Results window for one country. There are two calculations based on ellipsoidal / cartesian surface
    – MartinMap
    Jan 1, 2019 at 21:30
  • @MAP I did, those are always correct.
    – culebrón
    Jan 1, 2019 at 21:43
  • It seems that the area(geometry) function in the label expression ignores the properties of the project but of the layer. It can be solved with the transform(geom, source_auth_id, dest_auth_id) function. What version of QGIS are you using? What is the coordinate reference system of the layer? Jan 1, 2019 at 22:54

1 Answer 1


I also see that the function always calculates the planimetric area in the labeling.

A possible solution (I do not consider it robust but at least possible) is to reproject the polygons in the World_Cylindrical_Equal_Area CRS (EPSG:54034).

Since the spatial reference of the vector layer is the geographic system WGS 84 (EPSG: 4326), the transform function can be included in the labeling expression to reproject the geometry and calculate the area at the time of labeling:

'$area in calculator:' || ar || '\n$area in label:' || round( area( transform( $geometry, 'EPSG:4326', 'EPSG:54034') ) / 10000, 4) 

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