OpenPostcode

Ireland's only wholly free to use and calculate postcode.

Interactive OpenPostcode map - convert location to Google Maps, Bing, OSI, OpenStreetMap, and more. Perfect for anyone studying a specific location.

A fully extensible, independent, free and open geolocation code for a wide range of applications and precisions, efficiently describing single points and complex areas (released under the LGPL).
Born as a proof of concept that geolocation-postcodes can be trivial maths, and without the need for proprietary licenses and centralised management, it remains Ireland's most accurate postcode at 8 characters; while even at 7 characters at <3m average radial offset from a point - over 4 times more precise than Loc8code. For geolocation applications: at eight characters it extends to an accuracy of an average radial offset of ~.58m (inside an area just 1.2m x .92m), while the code is easily extended with even further characters. At 9 characters it is down to centimetre scale. At 10 characters it can provide geolocation coding for the entire globe. Precision calculations are available in spreadsheet format.

The code works at any level of precision.
 
At eight characters it has an average offset of 0.58m. At seven characters it describes an area 5.98m by 4.6m. At six, an area 30m by 23m - perhaps an average postcode sized area. At five, an area 150m by 115m. At four, a small area .75km by .57km. At just three characters an area 3.7km by 2.9km. At two characters an area 19km by 14km. And finally the country is divided into a 5 by 5 grid of approximately 93km x 72km areas.
 
For example, The Spire of Dublin is encoded as KFPX-WT7D/5. This might also be written as KFPX-WT (KFPX-WT/P with a checksum).

Digits Example  Checksum Precision  Applications
9     .24m x .18m  Precise geolocation functions.
8 KFPX-WT7D 5 1.2m x .9m (avg. offset ~0.58m)   Geolocation. Infrastructure (signage, fittings, poles, meters, etc.)
7 KFPX-WT7 U 5.98m x 4.6m (avg. offset <3m) Postcodes: individual buildings, entrances; infrastructure (bridges, junctions, etc.).
6 KFPX-WT P 30m x 23m  Many sites and campuses.
5 KFPXW M 150m x 115m  Larger campuses, street segments.
4 KFPX X .75km x .57km  Neighbourhood areas. 
3 KFP U 3.7km x 2.9km  Small area statistics, rough/private address, service calculations.
2 KF 3 19km x 14km  General regions, statistical regions, marketing, etc.
1 K F 93km x 72km  Coarser geographical statistics.
        Irregular regions can be described in terms of groups of postcodes of varying size.
  International
 
6 N962-65     J 3.5m x 4.6m Geolocation postcode for Hong Kong (example HSBC Tower).
7                 0.7m x 0.9m  
10 942GC-7JD54 W 2m x 2.9m World geolocation postcode (example Spire of Dublin).    
  4WMXJ-P5CCG G 2m x 2.9m International: Centre of the Öresundsbron/Øresundsbroen.
10 bdrd5tb4Md n 0.33m x 0.47m Global Geohash-36 (machine suitable code, base-36, case-sensitive).

On the whole locations nearby have similar codes. City Hall, Dublin, is at KFW5-X3L. The Central Bank is at KFW6-MW. The National Concert Hall is at KFWK-D2. The DCENR on Adelaide Road is KFXF-L6. While a house on the Blaskets is R374-CJ.

The code does not prescribe a format for display for individual codes. It is open to the specific application to apply formatting rules. For example, a postcode might prescribe the format KFPX-WT7 to delineate postal areas and specific addresses.

The code is open to any number of uses and required precision.

The parameters for an Irish postcode as set via "west=-10.75; north=55.5; wide=5.4; high=4.2; digits=7". Using the code on a world scale generates a geolocation code in 10 just characters. Likewise, the OpenPostcode for Hong Kong is defined by "west=113.8; north=22.6; wide=.7; high=.5; digits=6".

A checksum character is available at any precision level of the code.

It is short, as short as any other and as short as you need it to be. It is clear, avoiding character confusion. Easy to remember, while neighbouring codes are largely similar and distinct from UK Northern Ireland codes. It is accurate, to an average distance of under 3m at 7 characters. It is scaleable and extensible to any application or purpose from 1 character to 10 characters capable of covering the globe. It is flexible, not just about mail and addresses, but for all sorts of locations, points-of-interest, postboxes, railway bridges, TV masts, telephone poles, pylons, manholes, petrol stations, lay-bys, in fact any geolocation data. It does not categorise. It does not navigate. It just points (navigation is for other systems). Each postcode is verifiable as correct by a built in checksum character. It has a published mathematical algorithm, free to use and to adapt, based on earth coordinates. The codes are mathematically logical and orderly. There is no language discrimination between Irish or English. The codes are objective: there is no such thing as a "select area" or posh code; it is maths. It is entirely free and released under the LGPL license.

Links