Latitude, Longitude and Altitude format for geospatial information
Contents
Introduction
- The identification of the position on the earth by latitude and longitude (and altitude) is used by a lot of services on WWW. However, almost all the notations for them are different at each service. This situation expands the possibility to generate a meaningless discrepancy for geo-services. As for the notation of latitude longitude information, two styles will be possible with different usage. One is a notation to identify latitude and longitude separately. Another is a notation to identify as a set of latitude and longitude.
As for the former, Latitude and Longitude will be specified for a property name. Basic geo-vocabulary is a candidate which presents the notation for this. The latter will be identified as a latitude longitude data type. A lot of specifications including Dublin Core refer to W3CDTF. As a result, the notations for time are considerably united.
Formats
This notation is provided for by the analogy from W3CDTF. W3CDTF refers to ISO8601. Then this specification refer to ISO6709. And, this document defines a profile of ISO 6709 by restricting and qualifying the formats. The International Standard representation of latitude, longitude and altitude is ISO 6709. Its full reference number is ISO 6709-1983(E), and its title is "Standard representation of latitude, longitude and altitude for geographic point locations".
Declaration and qualification of valid geographic coordinate reference system
Data based on this profile has WGS-84 as geographic coordinate reference system. Note: WGS-84 would be the most popular geographic coordinate reference system that is supported as a standard on the GPS equipments.
Representations
- The formats are as follows. Exactly the components shown here must be present, with exactly this punctuation.
Latitude and Longitude in Degrees:
±DD.DDDD±DDD.DDDD/ (eg +12.345-098.765/)
Latitude and Longitude in Degrees and Minutes:
±DDMM.MMMM±DDDMM.MMMM/ (eg +1234.56-09854.321/)
Latitude and Longitude in Degrees, Minutes and Seconds:
±DDMMSS.SSSS±DDDMMSS.SSSS/ (eg +123456.7-0985432.1/)
where:
±DD = three-digit integer degrees part of latitude (through -90 ~ -00 ~ +90)
±DDD = four-digit integer degrees part of longitude (through -180 ~ -000 ~ +180)
MM = two-digit integer minutes part (00 through 59)
SS = two-digit integer seconds part (00 through 59)
.DDDD = variable-length fraction part in degrees
.MMMM = variable-length fraction part in minutes
.SSSS = variable-length fraction part in seconds
* Latitude is written in the first, and longitude is second.
* The sign is always necessary for each value.
Latitude : North="+" South="-"
Longitude: East ="+" West ="-"
* The integer part is a fixed length respectively.
And padding character is "0".
(Note: Therefor, it is shown explicitly that the first is latitude and the second is
longitude, from the number of figures of the integer part.)
* It is variable-length below the decimal point.
* "/"is a terminator.
Altitude can be added optionally.
Latitude, Longitude (in Degrees) and Altitude:
±DD.DDDD±DDD.DDDD±AAA.AAA/ (eg +12.345-098.765+15.9/)
Latitude, Longitude (in Degrees and Minutes) and Altitude:
±DDMM.MMMM±DDDMM.MMMM±AAA.AAA/ (eg +1234.56-09854.321+15.9/)
Latitude, Longitude (in Degrees, Minutes and Seconds) and Altitude:
±DDMMSS.SSSS±DDDMMSS.SSSS±AAA.AAA/ (eg +123456.7-0985432.1+15.9/)
where:
±AAA.AAA = variable-length altitude in meters [m].
* The unit of altitude is meter [m].
* The integer part and the fraction part of altitude are both variable-length.
BNF description
See this page at SVG MAP Lab
Examples
Mount Everest +27.5916+086.5640+8850/ South Pole -90+000+2800/ New York City +40.75-074.00/ Mount Fuji +352139+1384339+3776/ Tokyo Tower +35.658632+139.745411/
Ranged data
A couple of data
A_Couple_Of_LatLonAlt = LatLonAlt LatLonAlt
Example: +35.331+134.224/+35.336+134.228/
Sequence of data
Sequence_Of_LatLonAlt = LatLonAlt+
Example: +35.331+134.224/+35.336+134.228/+35.333+134.229/+35.333+134.227/
Use Cases
XML Encoding (Including GeoRSS/XML) <point>+35.36083+138.72750/</point>
HTML metadata (microformats) <meta name="geo.position" content="+47.1595+130.0894/" />
URL Encoding (REST) http://hoge.net/pl?point=+35.36083+138.72750/
See Also
This document draws on "Latitude, Longitude and Altitude on the Internet" (in Japanese).
A geographic information notation using SVG and RDF compatible metadata
Point Location 6709 an open-source Java parser and formatter
ISO6709 tools for Java
ISO6709 tools for Java Script
