parselatitude, parselongitude

  parselatitude(latitudeText)
  parselongitude(longitudeText)

The parselatitude and parselongitude functions parse a text (varchar) latitude or longitude coordinate, respectively, and return its value in decimal degrees as a double. The coordinate should be in one of the following forms (optional parts in square brackets):

[H] nnn [U] [:] [H] [nnn [U] [:] [nnn [U]]] [H] DDMM[.MMM...] DDMMSS[.SSS...]

where the terms are:

• nnn

  A number (integer or decimal) with optional plus/minus sign. Only the first number may be negative, in which case it is a south latitude or west longitude. Note that this is true even for DDDMMSS (DMS) longitudes - i.e. the ISO 6709 east-positive standard is followed, not the deprecated Texis/Vortex west-positive standard.

• U A unit (case-insensitive):

  • d

  • deg

  • deg.

  • degrees

  • ' (single quote) for minutes

  • m

  • min

  • min.

  • minutes

  • " (double quote) for seconds

  • s (iff d/m also used for degrees/minutes)

  • sec

  • sec.

  • seconds

  • Unicode degree-sign (U+00B0), in ISO-8559-1 or UTF-8
  If no unit is given, the first number is assumed to be degrees, the second minutes, the third seconds. Note that "s" may only be used for seconds if "d" and/or "m" was also used for an earlier degrees/minutes value; this is to help disambiguate "seconds" vs. "southern hemisphere".

• H A hemisphere (case-insensitive):

  • N

  • north

  • S

  • south

  • E

  • east

  • W

  • west
  A longitude hemisphere may not be given for a latitude, and vice-versa.

• DD

  A two- or three-digit degree value, with optional sign. Note that longitudes are east-positive ala ISO 6709, not west-positive like the deprecated Texis standard.

• MM

  A two-digit minutes value, with leading zero if needed to make two digits.

• .MMM...

  A zero or more digit fractional minute value.

• SS

  A two-digit seconds value, with leading zero if needed to make two digits.

• .SSS...

  A zero or more digit fractional seconds value.

Whitespace is generally not required between terms in the first format. A hemisphere token may only occur once. Degrees/minutes/seconds numbers need not be in that order, if units are given after each number. If a 5-integer-digit DDDMM[.MMM...] format is given and the degree value is out of range (e.g. more than 90 degrees latitude), it is interpreted as a DMMSS[.SSS...] value instead. To force DDDMMSS[.SSS...] for small numbers, pad with leading zeros to 6 or 7 digits.

EXAMPLE

insert into geotest(lat, lon)
  values(parselatitude('54d 40m 10"'),
         parselongitude('W90 10.2'));

CAVEATS

An invalid or unparseable latitude or longitude value will return NaN (Not a Number). Extra unparsed/unparsable text may be allowed (and ignored) after the coordinate in most instances. Out-of-range values (e.g. latitudes greater than 90 degrees) are accepted; it is up to the caller to bounds-check the result. The parselatitude and parselongitude SQL functions were added in version 6.00.1300132000 20110314.