Q:

How is a km in coordinate?

Anyone how much is a kilometer in coordinate for example I can suppose that every five coordinate I have one kilometer? Does it exist one relation in this way? Anyone can suggest me?

A:

On a sphere, the usual coordinates are angle measures, latitude and longitude. But if you move along the latitude at the equator by 1 km, the latitude changes only a little, whereas if you move along a latitude close to the north or south pole, the latitude may change arbitrarily much.
The relation that you want to obtain can thus only be valid approximatively, and at a certain region of the sphere.

