Converting between Degree Minute Second (DMS) and Decimal Degree (DD)

When working with Latitudes and Longitudes in Geomatics Information Science (GIS), there two ways that degrees can be represented that is:-
~ Degree Minute Second (DMS) and
~ Decimal Degree (DD)

In this article, am going talk about converting between two representations Degree Minute Second (DMS) and Decimal Degree (DD).

Notation

The notation for DMS is as follows

The notation for DD is as follows

Values

Now, the units of Minute Second might be new you. So here are the values;-
60" = 1'
60' = 1o
Its then just a simple matter of multiplications to see that there
3600" = 1o

More about this here

Example

1) Lets Convert from Degree Minute Second (DMS) to Decimal Degree (DD)
120o 30' 45"

The general approach is that: the degree part (120o) remains unchanged, then the second part (45") is divided by 60" and added to the minute part (30'). Finally the result is divided by 60' and added to the degree.

2) Lets Convert from Decimal Degree (DD) to Degree Minute Second (DMS)
120.5125o

This will be the reverse of the above and the general approach is that: the whole number part (120) remains unchanged, then the decimal part (.5125) is multiplied by 60' which result to 30.75'. The whole number part (30) again droped unchanged, then the remain decimal part (.75) is now multiplied by 60" to give the remaining seconds part as 45".

That is it!
Thanks for reading