Latitude and Longitude coordinates are often presented in degrees, minutes, and seconds, such as 39°45'30" (39 degrees, 45 minutes, 30 seconds). However, MapViewer can only plot values in decimal degrees. So, for example, 39°45' is referred to as 39.75° in MapViewer.

Converting from degrees, minutes, and seconds is actually quite easy. Consider the latitude value 39°25'30". This value needs to be converted to use it in MapViewer. There are 60 minutes in one degree and 3600 seconds in one degree. To convert minutes and seconds to decimal degrees, divide minutes by 60, divide seconds by 3600, and then add the results to obtain the decimal equivalent.

To convert 39°25'30" to decimal degrees

1. First, convert minutes and seconds to their degree equivalents and add the results.

25'/60 = 0.4167; 30"/3600 = .0083; and 0.4167 + 0.0083 = 0.425

2. Then, add this number to the number of degrees.

39 + 0.425 = 39.425

3. So, 39°25'30" = 39.425°

See Also

Introduction to Map Projections

Latitude and Longitude Coordinates

Using Scaling to Minimize Distortion on Latitude and Longitude Maps