CONVERTING UNITS

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 is 40°.	*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

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!"