Decimal degrees

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Decimal degrees (DD) is a notation for expressing

Positive latitudes are north of the equator, negative latitudes are south of the equator. Positive longitudes are east of the

A DMS value is converted to decimal degrees using the formula:

${\displaystyle \mathrm {D} _{\text{dec}}=\mathrm {D} +{\frac {\mathrm {M} }{60}}+{\frac {\mathrm {S} }{3600}}}$

For instance, the decimal degree representation for

38° 53′ 23″ N, 77° 00′ 32″ W

(the location of the United States Capitol) is

38.8897°, -77.0089°

In most systems, such as OpenStreetMap, the degree symbols are omitted, reducing the representation to

38.8897,-77.0089

To calculate the D, M and S components, the following formulas can be used:

${\displaystyle {\begin{aligned}\mathrm {D} &=\operatorname {trunc} (\mathrm {D} _{\text{dec}},0)\\\mathrm {M} &=\operatorname {trunc} (60\times |\mathrm {D} _{\text{dec}}-\mathrm {D} |,0)\\\mathrm {S} &=3600\times |\mathrm {D} _{\text{dec}}-\mathrm {D} |-60\times \mathrm {M} \end{aligned}}}$

where ${\textstyle \mathrm {\left\vert D_{dec}-D\right\vert } }$ is the absolute value of ${\textstyle \mathrm {D_{dec}-D} }$ and ${\textstyle \mathrm {trunc} }$ is the truncation function. Note that with this formula only ${\textstyle \mathrm {D} }$ can be negative and only ${\textstyle \mathrm {S} }$ may have a fractional value.

See also

• ISO 6709 Standard representation of geographic point location by coordinates
• geo URI scheme

References