[Qgis-developer] Wrong Area for large polygons in
vector/Geometry Tools/Export/Add Geometry Columns
Giovanni Manghi
giovanni.manghi at gmail.com
Mon Apr 9 08:35:43 EDT 2012
> Check, for example, polygons with ID 25967 and 26570: according to the table,
> the areas are
> 25967: 8550196769
> 26570: 1736474738
>
> while visual inspection indicates that 26570 is obviously much larger.
this depends on
http://hub.qgis.org/issues/4955
if you compute areas (with both the filed calculator or the "add
geometry columns tool") you get
ID Area_FC
25967 8550196769.93
26570 173647473841.47
that makes sense according to the size of polygons
> Both results are different than those calculated by R:
>
> 25967: 9294889613
> 26570: 205414657947
>
> Discrepancies with R are particularly large for polygons with area > 1E+10
Can't understand these differences.
-- Giovanni --
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