I have GIS software that can do this conversion but I need to know the actual formula / math involved. I'm writing code and need to perform a single conversion (WGS to EPSG:3071) so using a library, open source or not, involves too much overhead (20+ MB for one library). I don't need libraries of coordinate systems that will never be used. It would be best if I just write a function to perform the calculation.
How do I convert from WGS84 to EPSG:3071 (Wisconsin Transverse Mercator)?