3.2. Convert Decimal Coordinates to DDD MM.MMM
If you would like to convert Decimal Coordinates to DDD MM.MMM, take the integer (whole number) - positive is North and East, negative is South and West - and set it aside. The remaining decimals would be multiplied times sixty to get minutes.
Example: the Sears Tower in Chicago is located at 41.878928° -87.636415°. For the latitude...
Start with the number in decimal degrees
Positive is north, and take the whole number
Then take the remainder times 60
Round to three decimals
Therefore the latitude for the Sears Tower in Chicago is
41.xxxxxx = N41°
0.878928 x 60 = 52.73568
Now try the math on your own: Longitude -87.636415° will convert to W087° 38.185.
To reverse the process, take the minutes portion and divide by 60, then tag it on to the degrees:
W 087° 38.185
38.185 ÷ 60 = 0.636417
tag it onto the degrees to get 87.636417°
“West” is negative: -87.636417°
To carry it further to seconds beyond minutes, you do the same thing with the minutes that you did with the degrees. Take the integer off of the minutes and multiply the remaining decimal times 60. That will give you seconds. If you have Degrees, Minutes and Seconds...
- Start with the seconds and divide by 60. Add the minutes and you'll be in the format that Geocaching uses: H DDD MM.MMM
- To take it further to the decimal degrees, divide the minutes (MM.MMM) by 60 and add the decimal to the degrees. That will leave you in the format DDD.DDDDD. Remember, West and South are negative, East and North are positive. Coordinates in the US are N latitude (positive) and W longitude (negative).
Many thanks to Volunteer Forum Moderator Markwell for initially developing these instructions.