Dear all, here I am back with one of my usual "newbie" questions which I'm sure has such a simple answer that I already feel embarassed in advance! Here goes anyway... I'm trying to calculate the area and perimeter length of a polygon shapefile. Using the QGIS measuring tool and clicking along the outline of the polygon, I get an answer of approximately 663 km area with a perimeter of about 110 km... and those values seem about right. So what's the problem? The problem is that if I do the same using the Field Calculator, or the "Extract Add Geometric Columns" vector tool (not sure if the name is right, I'm using the Italian version), I get completely different answers: an area of 0.072189 and a perimeter of 1.13297 (not even sure in what units). The layer units are set to metres and reprojection is disabled. Help!! What am I doing wrong!? I could of course simply continue using the measuring tool, but I have a lot of polygons to calculate and some are very complex. Thanks for your usual patience, Sarah.
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