Background: I am doing some area statistics (how much of different properties is used for a specific type of use) based on ACAD-constructions. Both the from dxf converted shapes and the baselayer with all the properties weren't changed, but when I redid the calculations today in order to check for the source of some discrepancies, I stumbled upon several different numbers in my old and new statistics.

Therefore the question: How exact is the $area-function in QGis? Are errormargins by 10 to 100 square metres to be expected? (We're talking usual european field sizes, 50 hectars max)

  • 1
    Have you checked or changed the projection your data is in? that can affect area calculations: gis.stackexchange.com/questions/147147/…
    – MAJ742
    May 30 '18 at 12:47
  • Always the same, always EPSG 25833
    – Erik
    May 30 '18 at 12:48
  • The error does seem to not to exceed 0.3 per cent.
    – Erik
    May 30 '18 at 13:09
  • 1
    EPSG:25833 is UTM and applies scale factor 0.9996. It may have an effect but it depends how your data are converted from ACAD into GIS format.
    – user30184
    May 30 '18 at 13:09
  • I believe that a function is a tool that can be configured to receive calculations with a certain error, and the accuracy of your calculations is likely to depend on your source geodata ... Jun 3 '18 at 19:24

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