Decimal degrees

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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[change | change source]

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
DMS Object that can be unambiguously recognized at this scale N/S or E/W
at equator
E/W at
23N/S
E/W at
45N/S
E/W at
67N/S
0 1.0 1° 00′ 0″ country or large region 111.32 km 102.47 km 78.71 km 43.496 km
1 0.1 0° 06′ 0″ large city or district 11.132 km 10.247 km 7.871 km 4.3496 km
2 0.01 0° 00′ 36″ town or village 1.1132 km 1.0247 km 787.1 m 434.96 m
3 0.001 0° 00′ 3.6″ neighborhood or street 111.32 m 102.47 m 78.71 m 43.496 m
4 0.0001 0° 00′ 0.36″ individual street 11.132 m 10.247 m 7.871 m 4.3496 m
5 0.00001 0° 00′ 0.036″ a tree 1.1132 m 1.0247 m 787.1 mm 434.96 mm
6 0.000001 0° 00′ 0.0036″ a human 111.32 mm 102.47 mm 78.71 mm 43.496 mm
7 0.0000001 0° 00′ 0.00036″ commercial mapping 11.132 mm 10.247 mm 7.871 mm 4.3496 mm
8 0.00000001 0° 00′ 0.000036″ specialized mapping 1.1132 mm 1.0247 mm 787.1 µm 434.96 µm

References[change | change source]