Decimal degrees

Decimal degrees are the latitude and longitude geographic coordinates as decimal fractions.

Positive latitudes are north of the equator and less than zero latitudes are south of equator. Positive longitudes are east of the prime meridian and less than zero longitudes are to the west of the prime meridian. Latitude and longitude are usually listed as "Latitude, Longitude", in that order.

Precision

The radius of the semi-major axis (the distance from the center of Earth to the outside at the equator line) of Earth at the equator is 6,378,137.0 meters[1] resulting in a circumference of 40,075,161.2 meters. The number of decimal places required for a particular precision at the equator is:

Degree precision versus length
decimal
places
decimal
degrees
DMSObject that can be unambiguously recognized at this scaleN/S or E/W
at equator
E/W at
23N/S
E/W at
45N/S
E/W at
67N/S
0 1.01° 00′ 0″country or large region111.32 km102.47 km78.71 km43.496 km
1 0.10° 06′ 0″large city or district11.132 km10.247 km7.871 km4.3496 km
2 0.010° 00′ 36″town or village1.1132 km1.0247 km787.1 m434.96 m
3 0.0010° 00′ 3.6″neighborhood or street111.32 m102.47 m78.71 m43.496 m
4 0.00010° 00′ 0.36″individual street11.132 m10.247 m7.871 m4.3496 m
5 0.000010° 00′ 0.036″a tree1.1132 m1.0247 m787.1 mm434.96 mm
6 0.0000010° 00′ 0.0036″a human111.32 mm102.47 mm78.71 mm43.496 mm
7 0.00000010° 00′ 0.00036″commercial mapping11.132 mm10.247 mm7.871 mm4.3496 mm
8 0.000000010° 00′ 0.000036″specialized mapping1.1132 mm1.0247 mm787.1 µm434.96 µm

References

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