A problem by creating charts is simple reality that the surface of the ground, a surface curved in
A problem by creating charts is simple reality that the surface of the ground, a surface curved in three-dimensional space, must be represented in two dimensions like surface punt. This requires necessarily a certain degree of deformation, which can be treated by the use of projections which to the minimum reduce the deformation in certain areas. Moreover, the ground is not a regular sphere, but its form is in the place known as geoid, which is a form highly irregular but exactly knowable and calculable.