EPSG
EPSG guidance note #7.
2002-11-22
Applies to 2D and the horizontal component of 3D ellipsoidal systems.
In the formulas that follow, the coordinate strings are symbolically represented as follows: deg decimal degrees adeg absolute value of decimal degrees ideg integer degrees sdeg signed integer degree min real-number minutes imin integer minutes sec real-number seconds lathem, lonhem hemisphere abbreviation In this conversion (both forward and reverse) the hemisphere parameter remains unchanged and retains its position in the respective coordinate strings. Forward calculation from degH representation to DMSH representation: ideg = INT(adeg) min = (adeg - ideg) * 60 imin = INT(min) sec = (min - imin) * 60 Reverse calculation from DMSH representation to decimal degree representation: adeg = (ideg + imin/60 + sec/3600)