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 the hemisphere parameters retain their values but change their positions in their respective coordinate strings from the end of the strings to the beginnings (both forward and reverse). Forward calculation from Hdeg representation to DMSH representation: First, re-order fields from lathem, lat_adeg and lonhem, lon_adeg to lat_adeg, lathem and lon_adeg, lonhem Then ideg = INT(adeg) min = (adeg - ideg) * 60 imin = INT(min) sec = (min - imin) * 60 Reverse calculation from DMSH representation to Hdeg representation: adeg = (ideg + imin/60 + sec/3600) Then re-order fields from lat_adeg, lathem and lon_adeg, lonhem to lathem, lat_adeg and lonhem, lon_adeg