Open location code

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The Open Location Code (OLC, Plus Code ) is a coding system for geographic coordinates . It was developed in a Google- related engineering office in Zurich and published at the end of 2014. Compared to the conventional notation in degrees, it is compact, clear and easy to adapt to the required accuracy. The spelling stipulates that after eight symbols a plus sign (“+”) is inserted for easier readability, which is why the term Plus Code prevailed.

If the name of a nearby place is given in addition to the code, the code can often be shortened to four to seven digits, for example like this: X8GJ + F8 Weimar

specification

OLC is a grid-based system. Each code describes an area that is delimited by two parallels and two meridians from a solid grid and that is determined by its southwest corner and its size. The largest grid has blocks of 20 × 20 degrees (9 rows and 18 columns) and is divided up to four times into 20 × 20 sub-blocks. This is divided into 5 by 4 sub-blocks. The table below shows the different block sizes with their maximum near the equator . The block width decreases with the distance to the equator.

Code length 2 4th 6th 8th + 10 11
Block size 20 ° 1 ° 0.05 ° (3 ′) 0.0025 ° (9 ″) 0.000125 ° (0.45 ″)
Approximate size 2200 km 110 km 5.5 km 275 m 14 m 3.5 m

The full grid uses deviations from the south pole (−90 °) and from the antimeridian (−180 °) expressed in a base 20 representation. To avoid words being read or written incorrectly, the coding excludes vowels and symbols that can easily be confused with each other. The following table shows the assignment.

Characters in base 20 0 1 2 3 4th 5 6th 7th 8th 9 10 11 12 13 14th 15th 16 17th 18th 19th
Code characters 2 3 4th 5 6th 7th 8th 9 C. F. G H J M. P Q R. V W. X

The code starts with up to five pairs of digits, each consisting of one digit for latitude and one for longitude. The largest blocks only have two digits. After 8 digits, a plus sign ("+") is inserted as a separator to make it easier to read. After 10 digits in each division, sub-blocks are encoded in a single code digit as follows:

Longitude →
Latitude
↓ 		R. V W. X
J M. P Q
C. F. G H
6th 7th 8th 9
2 3 4th 5

Areas larger than an 8-digit block can be specified by replacing any number of trailing digits before the plus sign with the digit 0 and nothing after the plus sign.

example

Location of the south tower of Cologne Cathedral

  • 9F : Specification of a 20 ° high and 20 ° wide spherical rectangle that includes the northern part of Europe and Germany
  • 9F28WX : Limit to Cologne with an accuracy of 0.05 ° = 5.5 km
  • 9F28WXR4 + FW : Limit to 14 m
  • 9F28WXR4 + FWR : Limit to 3 m

9F28 stands for the Cologne-Düsseldorf area, 9F28WX for the district and R4 + FWR for the house number. This is where OLC differs from other referencing systems, such as MapCode , in which the similarity of the codes does not allow conclusions about spatial proximity. In this way, the OLC helps with the addressing of houses if street maps are missing.

In comparison, in conventional notation there are different possible notations for the same coordinates, for example:

  • N 50 ° 56 ′ 28.1040 ″, E 6 ° 57 ′ 26 ″ (degrees, minutes, seconds - notation)
  • 50.94114 north latitude, 6.95728 east longitude (decimal notation)

See also

Individual evidence

  1. ↑ 2 million Brazilians receive addresses for the first time - thanks to Google Maps. In: Heise.de. Heise, January 6, 2020, accessed on January 6, 2020 .

Web links