Degrees/Minutes/Seconds (DMS) and Decimal Degrees (DD) are two different ways of expressing geographic coordinates, such as latitude and longitude¹.
**Degrees/Minutes/Seconds (DMS)**: This system represents angles as a combination of degrees, minutes, and seconds. For example, the geographic coordinate expressed in degrees-minutes-seconds for New York City is:
- LATITUDE: 40 degrees, 42 minutes, 51 seconds N
- LONGITUDE: 74 degrees, 0 minutes, 21 seconds W¹
**Decimal Degrees (DD)**: This system represents angles as a single decimal number. It's often used for ease of calculations³. For example, New York City in decimal degrees is:
- LATITUDE: 40.714
- LONGITUDE: -74.006¹
You can easily convert between these two formats. There are 60 minutes in a degree and 60 seconds in a minute². So, to convert from DMS to DD, you would take the number of minutes, divide by 60, and add that to the degrees. Then, take the number of seconds, divide by 3600 (since there are 60 seconds in a minute and 60 minutes in a degree), and add that to the result².
For example, to convert 40 degrees, 42 minutes, 51 seconds to decimal degrees:
- 42 minutes ÷ 60 = 0.7
- 51 seconds ÷ 3600 = 0.0141667
- Add these together with the 40 degrees to get 40.7141667 degrees².
Conversely, to convert from DD to DMS, you would take the decimal part of the degree, multiply by 60 to get minutes, and then take the decimal part of that result, multiply by 60 again to get seconds².
For example, to convert 40.714 degrees to DMS:
- The whole number part is 40 degrees.
- Multiply the decimal part by 60: 0.714 * 60 = 42.84. So, 42 minutes.
- Multiply the decimal part of the minutes by 60: 0.84 * 60 = 50.4. So, 50 seconds (rounded to the nearest whole number)².
In summary, the choice between DMS and DD often depends on the context and the need for precision or simplicity¹³.