the author of this app says:
Pocket S-Calc is a series of programs designed for the land surveyor, civil engineer or anyone else who has the need for creating and processing coordinate data. Using S-Calc on your Pocket PC, you will be able to transform and rotate coordinate systems from one base to another, instantly perform setting out (inverse) calculations on data produced or pre-loaded into the Pocket PC. S-Calc will also calculate coordinates along road straights and curves, again storing the data generated to the Pocket PC for plotting or calculations. There is also a function for calculating coordinates from drawings.
The trial version is fully functional but limited to loading 25 data points and the file save facility is not operable.