Mapping

Syntax:

        set mapping { cartesian | spherical | cylindrical }

Data for splots are usually in regular Euclidean space and are provided in Cartesian coordinates. Such 3-d data require three coordinates (x, y and z) or one coordinate (only z) in each line in the data file. In order to be able to use spherical or cylindrical coordinate systems, use the set mapping command. In both cases two coordinates are expected in each line of the data. For a spherical coordinate system, these are theta and phi (in units as specified by set angles) and the mapping is:

        x = cos( theta ) * cos( phi )
        y = sin( theta ) * cos( phi )
        z = sin( phi )

For a cylindrical coordinate system, the mapping uses two variables, theta (in units as specified by set angles) and z:

        x = cos( theta )
        y = sin( theta )
        z = z

Again, note that mapping will affect data file splots only.