Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.
Sign up to join this community
I have a layer with several polygons in it and would like to find out the maximal extend of each polygon in each direction, e.g. the western- and easternmost point etc.
Just tracing the polygon with the cursor and checking the coordinates seems a little imprecise.
How would I go about that?
Open the fieldcalculator and use these expressions:
x_min($geometry), x_max($geometry), y_min($geometry), y_max($geometry)
To get the entire point geometry, not just x or y value, you can get all vertices and test whether its x or y value is maximum, like this:
geom_to_wkt(
array_first(
array_filter(
array_foreach(
generate_series(1,num_points($geometry)),
point_n($geometry,@element)
),
y(@element) = y_max($geometry)) -- change the filtere here depending on which point you want. E.g. to x(@element) = x_min($geometry))
)
)
