I would like to do the following:
- Get the area of each soilscape type
- Calculate the sum of area per boundary
I'm trying to do the following but seems the output is always "0"
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1What spatial reference is your data? It could be geographic which would make your area unmeaning. The geometries could be bad which could interfere with the area calc. Probably the best way of getting combined areas is, after individual polygons are calculated, open a copy of the DBF file (part of a shapefile, you might need to save as if not already a shapefile) in Excel (or similar) and create a pivot table.– Michael StimsonCommented Jun 28, 2017 at 2:25
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1 Answer
Duplicate the layer, and perform a dissolve operation to make a polygon for every kind of soilscape How to dissolve based on attribute with QGIS
Then calculate the geometry of every polygon in a new field. Try if it works this way, maybe it is not the most elegant, but it may work for you.
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2This will work, but reproject to an appropriate equal-area projection first. Commented Jun 28, 2017 at 2:45
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Then find and fix invalid geometries faunaliagis.wordpress.com/2013/08/14/… or gis.stackexchange.com/questions/167421/… Incorrect ring orientation and self intersections can make the area calcs untrustworthy at best or crash QGIS at worst. Commented Jun 28, 2017 at 4:57