Points on which we may all agree.
1. Every point has a distinct longitude and latitude. A longitude is a line where all sundials are showing the same time. A latitude is determined by the angle to the pole star (in northern side of earth) or by angle to southern axis of apparent celestial rotation.
2. Longitude lines are straight, in the sense that they are the shortest distance across the surface of the earth between two points on the longitude line.
3. Longitude lines all intersect at the geographic north pole (and perhaps at the south pole, but that depends on the model chosen)
Where we may disagree
4. The surface distance between lines of latitude is about 111km per degree, for any latitude whatsoever.