1

I have two shapefiles, one corresponding to census tracts and the other is precincts. I'd like to find the proportion of area of intersection of each precinct with every tract that it overlaps with.

I saw a couple of other questions on here about doing this (for example: Calculating proportional area of polygon within another layer's polygon using QGIS), but I get NULL values populating the area field of the resulting layer every time I try their solution.

Screenshot: enter image description here

The last column area is the one in question in the screenshot above. I am new to QGIS.

Vince
  • 20,017
  • 15
  • 45
  • 64
Sachin Rammoorthy
  • 111
  • 1
  • 1
    Just use the Overlap analysis algorithm in the Processing Toolbox. – Ben W Sep 15 '22 at 23:25
  • make sure that both layers have the same CRS – eurojam Sep 16 '22 at 05:49
  • Pretty sure you could just do a union. If the area isn't auto-calculated, open the field calculator and type $area and run it. Make sure your coordinate systems are the same and that the coordinate systems' units are in meters (or feet) so that the area calculation has usable units – jdavid05 Sep 16 '22 at 18:00

0 Answers0