# Degrees conversion

#### Yuseph

##### Junior Member
Yo guys,

Why do we need to convert decimal degrees into degrees minutes seconds ?
Since radians can only be converted to decimal degrees and we need decimal degrees to convert to rad.
Whats the point handling degrees minutes second a° b' c" ?

#### pka

##### Elite Member
Why do we need to convert decimal degrees into degrees minutes seconds ?
Since radians can only be converted to decimal degrees and we need decimal degrees to convert to rad.
Whats the point handling degrees minutes second a° b' c" ?
Radians are numbers, Degrees are just ghosts left in the machine.

#### Dr.Peterson

##### Elite Member
In some applications, such as navigation -- in fact, probably all applications in the not-too-distant past -- it has been traditional to use DMS format (sexagesimal units). I am not aware of any reason to continue doing so, so I would say it is only needed if someone demands it. It's mostly a historical oddity, ultimately going back to the Babylonians' base-60 number system.

So some trigonometry courses still teach it, while others consider it unnecessary (especially since, if you need to do it, your calculator can often do it for you).

#### JeffM

##### Elite Member
Probably because most historical work that is still valid uses that system. If you don't know it, you can't take advantage of a great deal of previously done work, for example any blueprint or surveyer's map older than about 30 years.

For practical work you may well need to understand it even if you do not use it prospectively. Academics (other than historians) need not worry about whether they can construe old documents, but practical people often need to construe stuff that was recorded before everything was computerized.