they curve the longitude lines.
distortion
A small area map.
There is always some distortion.
The stretching, bending, and enlarging of areas on a map due to the curvature of the earth.
some landmasses
Distortion of shapes, sizes, and distances is likely to occur when cartographers represent the three-dimensional Earth on a two-dimensional map. This distortion is known as map projection, where different map projections prioritize different aspects such as area, distance, or direction. It is impossible to accurately represent the spherical Earth on a flat map without some degree of distortion.
Cartographers
When cartographers represent the three-dimensional Earth in two dimensions, distortions in the shape, size, distance, or direction of geographic features are likely to occur. This is because it is impossible to accurately capture the true nature of the Earth's surface on a flat map without some form of distortion. Different map projections are used to minimize specific types of distortion depending on the purpose of the map.
Cartographers
Cartographers.
Cartographers are map makers.
Because it's almost impossible to make a 3D object correctly placed in 2D. The different map projections are different people trying to be the most correct on their map projections. There's always going to be distortion... each projection has its pros and cons.
map keys
map maker
keys
Using a projection.
A person who reads a map is called a map reader or a navigator.