equidistant system

equidistant system

[¦ē·kwə¦dis·tənt ′sis·təm]
(mathematics)
A system of parametric curves on a surface obtained by setting surface coordinates u and v equal to various constants, where the coordinates are chosen so that an element of length ds on the surface is given by ds 2= du 2+ F dudv + dv 2, where F is a function of u and v.