A map’s geographic coordinates can be given in Decimal Degrees (DD, like 121.135°) or in Degrees, Minutes and Seconds (DMS, like 121°8’6“), which is more common.
Conversion
Basic concept:
- The whole units gives the degrees
- Multiply the decimal portion by 60; the whole units gives the minutes
- Again, multiply the decimal portion multiplied by 60; the whole units gives the seconds
- Puts the number together
Formula:
Knowing that 1° = 60' = 3600", let’s say dd = 121.135
- d = integer(dd) = 121°
- m = integer((dd - d) * 60) = 8’
- s = (dd - d - m / 60) * 3600 = 6“
Source: How to Convert Decimal Degrees into Degrees, Minutes, Seconds