Geographic Names Information System - 20 of 25

Geographic Names Information System FAQs - 25 Found

All of the coordinates (latitude and longitude) in Geographic Names Information System seem incorrect. What is the problem?

One might confuse the difference between degrees/minutes/seconds and Decimal Degrees. To convert from decimal degrees to degrees/minutes/seconds with 45.63248 as an example:


1) Subtract 45, leaving only the decimal .63248. Keep 45 for later reference.


2) Multiply by 60, to obtain 37.94880 – 37 is the number of minutes; 37 then will follow 45 degrees.


3) Subtract 37 to leave only .94880.


4) Multiply by 60 once again to obtain 56.92800, and round to 57, which represents the seconds.


This yields 45 degrees, 37 minutes, 57 seconds.


To convert from degrees-minutes-seconds to decimal degrees using 45 degrees, 37 minutes, 57 seconds as an example:


1) Begin with 57 seconds and divide by 60 to obtain .95000.


2) Add the 37 minutes to yield 37.95000.


3) Divide by 60 once again to obtain .63250.


4) Add the 45 degrees to obtain 45.63250.


Notice that rounding less than one-tenth of a second changes the conversion by .00002 degrees.

Tags: Maps, Coordinates, Topographic, Geospatial, Features, Geographic Names Information System (GNIS), Latitude and Longitude