I'm currently trying to parse a shapefile (http://www.esri.com/library/whitepapers/pdfs/shapefile.pdf) with c++. While I have no problems parsing all the data I need, there is a problem with the coordinates. I got a description file for the data, which states that the used projection is "ETRS89 (Ellipsoid: GRS80), UTM (Zone 33)".
I need all points to be in lon/lat format. I spent the whole day googling around to find a solution for this problem, but there doesn't seem to be one.
33354891.477852, 6060028.67074774 ^ ^ X (E) Y (N)