This module will convert any 2D or 3D, 2 space or 3 space field from
rectangular coordinates to polar, and vice versa. The output field is always
an irregular field, but the input can have any uniform or type setting.
When converting into polar coordinates, the output angles will be in the
range of 0 to 2*pi. When converting from polar to rectangular, any angles
can be used, but it is possible to overlap data if the range of angles is
greater than 2*pi.
For cylindrical coordinates, points along the z-axis will have a
radius equal to zero, and therefore an undefined angle. the atan2 function
will usually set this angle to 0 or PI. For that reason, polar to rectangular
to polar conversions will not always produce the original input field, though
no significant data is lost. For spherical coordinates, this effect only
concerns points located at the origin.
The Polar Type parameter is removed for 2 space fields since
cylindrical coordinates are assumed.