> You seem to be approaching things from a Cartesian perspective, but GIS almost always works in spherical coordinates because the earth is (approximately) a sphere
Actually no, I'm complaining about the exact opposite. I want to be working in spherical native coordinates, but QGIS seems to treat "degrees" as just another fixed unit of length measurement rather than an angular measurement!
For example I had the measurement projection set to "cartesian", which I would have expected to either give me the linear distance from (X,Y,Z) to (X,Y,Z), or the linear distance between (Lat,Lon) on an approximation of the earth's surface (either sphere or ellipsoid). Instead, it was treating (Lat, Lon) as if they were (X,Y) coordinates on a flat map and doing Pythagorean theorem on the angular measurements, resulting in the longitudinal distance being off by a factor of cos(latitude) !
I can see no paradigm in which such a result would ever be desired, apart from QGIS fundamentally working in terms of linearized projections, with WGS84/spherical coordinates being added on as an afterthought.
Actually no, I'm complaining about the exact opposite. I want to be working in spherical native coordinates, but QGIS seems to treat "degrees" as just another fixed unit of length measurement rather than an angular measurement!
For example I had the measurement projection set to "cartesian", which I would have expected to either give me the linear distance from (X,Y,Z) to (X,Y,Z), or the linear distance between (Lat,Lon) on an approximation of the earth's surface (either sphere or ellipsoid). Instead, it was treating (Lat, Lon) as if they were (X,Y) coordinates on a flat map and doing Pythagorean theorem on the angular measurements, resulting in the longitudinal distance being off by a factor of cos(latitude) !
I can see no paradigm in which such a result would ever be desired, apart from QGIS fundamentally working in terms of linearized projections, with WGS84/spherical coordinates being added on as an afterthought.