New answers tagged area
You can use the GroupStats plugin to achieve your goals. Just make sure to add the area column to your data table. Here's a link to a tutorial for the plugin GroupStats
In case I understand correctly, the common attribute for your groups is a weight attribute? Then you could use any of the dissolve functions in the toolbox, using that weight-field for dissolving (receiving probably multipart polygons). Next step would be to add a new area-field to your layer in the field calculator, using the $area expression to calculate ...
You can use OpenRouteService to add custom avoid areas / danger zones etc. The only alternative seems to be BRouter corresponding to the wiki overview.
You can do this by using a field in your layer's attribute table as the source for the buffer distance, rather than specifying the distance manually. This works in either the Buffer Wizard or the Buffer geoprocessing tool. You would first need to create a field in your feature class, then populate it with the buffer distances you'd like to use for each ...
You can create a Virtual field which updates features automatically based on the expression you insert. So in your case, it would be: $area You will need to create a Project for the shapefile (if you haven't done so already) as virtual fields are stored in the project files (.qgs). Hope this helps!
Have you checked that the transmission buffer and the merged datasets are in the same coordinate system? Also with your dissolve in the dissolve field, select dissolve all if you want to dissolve everything in that dataset to one polygon. Lastly have you tried Union instead of merging them as merge will give you 4 overlapping polygons whereas in Union ...
Yes, if you want ST_Area() on a bare geometry to return a planar area, you need to use an area-preserving CRS. GEOS is not magic, it just works in whatever units are handed to it, assuming cartesian math, so the expectation in a planar CRS if you want useful areas/lengths etc.
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