HOW TO CONVERT DECIMAL LATITUDES AND LONGITUDES TO DEGREES, MINUTES AND SECONDS
|"Lou, Maybe you remember that latitude and longitude are usually given in degrees, minutes and seconds. And that a minute is 1/60th of a degree; and a second is 1/60th of a minute!"|
|"Sure, I remember that!"|
|"But sometimes degrees of latitude and longitude are given in decimals! And you may need to convert the decimal version into degrees, minutes and seconds!"|
|"You mean like if I'm told that a house at 1 Parade Place in Brooklyn has a latitude of 40.6530190° and a longitude of minus 73.9659271°? And I want to know what that is in decimals? So what's the procedure?!"|
|"First, let's get settled whether the latitude is north or south and whether the longitude is east or west! Sometimes the decimal version will indicate that directly: for example, latitude 27.87682° N or longitude 18.776789° W. But sometimes there is no N, S, E or W. Instead, you may see a latitude written as 40.665° or +40.665°. Both of these numbers are positive numbers and mean the latitude is a NORTH latitude."|
"A negative number for latitude, such as -7.48° (if it's negative, the minus is always shown), is a SOUTH latitude!"
"And for longitude, if there's no E or W, and if the number is positive
(such as 128.3425° or +128.34°), then the longitude is EAST. If the number is negative, such as -73.9917° (the minus is always shown if the number is negative), then the longitude is WEST!"
|"OK!"|| POS. LATITUDE = NORTH|
NEG. LATITUDE = SOUTH
POS. LONGITUDE = EAST
NEG. LONGITUDE = WEST
|"I see I got you boxed in, Lou! OK! So let's take the latitude (40.6530190°) of the house on Parade Place first! These are the steps:|
|a. The number is positive so its a NORTH latitude. So 40.6530190° is 40.6530190° N.
||e. Multiply the remaining 0.18114' by 60 to get the number of seconds: 0.18114 x 60 = 10.8684 seconds (10.8684").|
|b. Break up the 40.6530190° into 40° + 0.6530190°. So the number of whole degrees
|f. Round off to the nearest whole number of seconds: 10.8684 seconds becomes 11 seconds. (If you've forgotten how to round off numbers, go to the Toolbox Menu and click on Rounding Off Numbers.)|
|c. Multiply the remaining 0.6530190° by 60 to get the number of minutes: 0.6530190 x 60 = 39.18114 minutes (39.18114').
||g. So, the latitude is 40& 39' 11". And as we said, since it is a positive number, the latitude is a NORTH latitude.|
|d. Break up the 39.18114' into 39' + 0.18114'. So the number of whole minutes is 39'.
||h. So the final answer for the latitude|
is 40° 39' 11" N."
|"Now let's do the longitude (-73.9659271°)! We work the same way:|
|a. The number is negative so the latitude is WEST. So -73.96599271° = 73.96599271° W.
||e. Multiply the remaining 0.959562' by 60 to get the number of seconds: 0.959562 x 60 = 57.57372 seconds (57.57372").|
|b. Break up the 73.96599271° into 73° + 0.96599271°. So the whole number of degrees is 73°.
||f. Round off to the nearest whole number of seconds: 57.57372 seconds becomes 58 seconds. (If you've forgotten how to round off numbers, go to the Toolbox Menu and click on Rounding Off Numbers.)|
|c. Multiply the remaining 0.96599271° by 60 to get the number of minutes:
0.96599271 x 60 = 57.959562 minutes (57.959562').
||g. So, the longitude is 73° 57' 58". And since the longitude was originally given as negative, we know it is a WEST longitude.|
|d. Break up the 57.959562' into 57' + 0.959562'. So the whole number of minutes is 57'.
||h. So the final answer for the longitude is 73° 57' 58" W!"|
|"So, my friend Lou, try out some conversions! Go do the quiz!"|
| LINK TO QUIZ|
© 2000 David J. Leveson