PMAP                     Map Physical Coordinates to World

 y = PMAP(expr,function)

    Converts a specified physical x or y coordinate to its world
    coordinate value, as defined by the WINDOW statement; or vice versa.

        expr    Specifies the x or y coordinate to be converted.

    function    A value in the range 0 to 3; specifies what the PMAP
                function is to do, as follows:

                0   Maps world coordinate x to physical coordinate x
                1   Maps world coordinate y to physical coordinate y
                2   Maps physical coordinate x to world coordinate x
                3   Maps physical coordinate y to world coordinate y