The coordinates for equations dealing with cylindrical and spherical conduction are derived by factoring in the volume of the thickness of the cylindrical control. Coordinates are placed into a Cartesian model containing 3 axis points, x, y, and z.

projections of the surface of a (nearly) spherical body that preserves the longitudes and latitudes as coordinates.

Ivan Istvan Mueller has written:

'Introduction to surveying' -- subject(s): Surveying

'Spherical and practical astronomy' -- subject(s): Spherical astronomy

'Gravimetic and celestial geodesy' -- subject(s): Dictionaries, Geodesy

'Reference coordinate systems' -- subject(s): Coordinates, Geodetic surveys, Inertial reference systems, Spherical coordinates, Standards

Curvilinear coordinate systems are a means of describing an object/point's position based on angle and distance from the origin. For example, polar coordinates are Curvilinear coordinates for R2 (2D space). Spherical coordinates are Curvilinear coordinates for R3 (3D space) If you need to know more:

http://en.wikipedia.org/wiki/Curvilinear_coordinates

Using the spherical coordinate system, they would be (6378 km, 40, -120).