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Parse geo coordinate¤

Description of the plugin¤

This plugin parses and normalizes geographic coordinates.

The input is a geographic coordinate (or “geocoordinate”) expressed as a single text string, and the output is the normalization of the geographic coordinate, consisting of both latitude and longitude, in the form (latitude, longitude). For this to work, the input must contain a separating comma (,) between the latitude and the longitude. Otherwise, the coordinates (0, 0) are returned by convention, instead of throwing an error.

Geographic coordinate system¤

The term “geocoordinates” is a shortened form of “geographic coordinates”, specifically used in technical contexts such as ours. Both —“geocoordinates” and “geographic coordinates”— are synonyms that refer to a location on Earth, expressed by the (angular) coordinates of latitude (north/south) and longitude (east/west).

The origin of this coordinate system is known as the Null Island. The positive direction of latitude is —by definition— the cardinal direction north, whereas the positive direction of longitude is east. Lines of constant longitude are known as meridians, whereas lines of constant latitude are known as parallels or circles of latitude. The meridian with 0° longitude is known —informally— as the prime meridian, and —formally— as the IERS Reference Meridian (IRM), or International Reference Meridian. The acronym “IERS” stands for “International Earth Rotation and Reference Systems Service”. The parallel with 0° latitude is the equator.

Geographic coordinates are dimensionless numbers for measuring and expressing angles. By convention, these angles are expressed in degrees, not in radians. This means, for the range of values for latitude and longitude, the following:

  • Latitude (φ): range –90° ≤ φ ≤ +90°

    • –90° → South Pole
    • 0° → Equator
    • +90° → North Pole

  • Longitude (λ): range –180° ≤ λ ≤ +180°

    • 0° → Prime Meridian (Greenwich)
    • +180° → directly east of Greenwich (International Date Line eastward)
    • –180° → directly west of Greenwich (International Date Line westward)

The meridian at 180° is known as the antimeridian or, simply, the 180th meridian.

Normalization of geographic coordinates¤

Normalization converts varied geolocation formats into a standard numeric form in decimal degrees: (latitude, longitude).

The input is expressed in degrees-minutes-seconds (DMS). Each portion is accompanied by the corresponding symbol:

  • Degrees (°)
  • Minutes (′)
  • Seconds (″)

Example¤

An example of the normalization of the geographic coordinates "51°20.519' N,12°22.443' E" is (51.3419833, 12.37405). This stems from the following calculation:

Latitude = 51 + 1⁄60 · 20.519 = 51.3419833° N,
Longitude = 12 + 1⁄60 · 22.443 = 12.37405° E.

A bit more detailed:

  1. First, the input is parsed: The latitude is 51°20.519' N, the longitude is 51°20.519' N. As stated, north (N) and east (E) are positive by convention. Correspondingly, south (S) and west (w) are negative.
  2. Next, each of these components is split into their portions:
    • 51°20.519' N corresponds to 51 degrees and 20.519 minutes.
      • Notice that the portion 20.519 minutes contains, itself, a decimal number, instead of the degrees-minutes-seconds format. This is because decimal degrees and minutes are permitted as a form of mixed format by our plugin.
      • Fully written in DMS format, this would be 51°20'31.14''N. This comes from the conversion of the fractional part: 0.519’ · 60 = 31.14’‘.
    • 12°22.443' E corresponds to 12 degrees, 22.443 minutes.
      • Once more, the portion 22.443 minutes is a mixed format, where instead of minutes and seconds, we write the minutes in decimal format to include the seconds.
  3. Finally, the DMS format of the input is normalized according to the following conversion formula: decimal degrees = degrees + 1⁄60 · minutes + 1⁄3600 · seconds.

Examples¤

Notation: List of values are represented via square brackets. Example: [first, second] represents a list of two values “first” and “second”.

Example 1:

  • Input values:

    1. [51°20.519' N, 12°22.443' E]

  • Returns: [GeoCoordinate(51.34198333333333,12.37405)]

Example 2:

  • Input values:

    1. [51°20'31.14'' N, 12°22'26.58'' E]

  • Returns: [GeoCoordinate(51.34198333333334,12.37405)]

Example 3:

  • Input values:

    1. [0°0'0'' N, 0°0'0'' E]

  • Returns: [GeoCoordinate(0.0,0.0)]

Example 4:

  • Input values:

    1. [47° 45' 3.8736'' N, 120° 44' 24.4860'' W]

  • Returns: [GeoCoordinate(47.751076,-120.740135)]

Example 5:

  • Input values:

    1. [35° 39' 10.1952'' N, 139° 50' 22.1208'' E]

  • Returns: [GeoCoordinate(35.652832,139.839478)]

Parameter¤

None

Advanced Parameter¤

None

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