DMS and decimal-degree coordinates
Aviation coordinates may be written as degrees, minutes, and seconds (DMS), degrees and decimal minutes, or decimal degrees. All three describe latitude and longitude, but charts, GPS systems, flight-planning software, and databases may expect different formats.
DMS to decimal degrees
Use decimal degrees = degrees + minutes ÷ 60 + seconds ÷ 3600. For example, 47° 30' 00" becomes 47.5000°. For 47° 27' 30", calculate 47 + 27/60 + 30/3600, which gives 47.4583°.
Hemisphere signs
North and east coordinates are normally positive in signed decimal-degree format. South and west are negative. That sign is essential. A longitude of 97° west is written approximately -97.0000°, not +97.0000°.
Decimal degrees to DMS
The whole-number part gives degrees. Multiply the remaining decimal by 60 to get minutes. Then multiply the remaining fraction of a minute by 60 to get seconds. Apply N, S, E, or W from the original sign.
Degrees and decimal minutes
Some aviation systems use degrees and decimal minutes instead of seconds. To convert DMS to that form, divide seconds by 60 and add the result to the minutes. Do not accidentally interpret decimal minutes as decimal degrees.
Why precision matters
One minute of latitude is approximately one nautical mile. That makes coordinate-format mistakes operationally meaningful. A misplaced decimal or hemisphere error can shift a point far from the intended location.
Common entry mistakes
Watch for west longitude entered as positive, minutes or seconds greater than 59, swapped latitude and longitude, and copying a coordinate from one format into a field expecting another. When software allows it, visually verify the plotted point before relying on it.
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