Data source: EPSG
Information source: EPSG guidance note #7.
Revision date: 2002-11-22
Remarks: 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