Project

os_national_grid

0.0
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Transforms OS National Grid (OSGB36) to WGS84 coordinates using official Ordnance Survey methods.
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 Popularity
Downloads
726
Stars
0
Forks
0
Watchers
1
 Releases
Current version
0.1.0
Total releases
1
First release
2025-06-06
Latest release
2025-06-06
 Pull Requests
Open Pull Requests
0
Closed Pull Requests
0
Merged Pull Requests
1
Pull Request Acceptance Rate
100%
 Development
Primary Language
Ruby
Licenses
MIT
Average date of last 50 commits
2025-06-05
Reverse Dependencies
0

 Dependencies
 Project Readme

OsNationalGrid

Gem Version

OsNationalGrid is a Ruby gem that provides accurate transformations between the Ordnance Survey National Grid (OSGB36) and WGS84 (latitude/longitude) coordinate systems.

It uses the official mathematical transformations from the Ordnance Survey, including a Helmert transformation for precise conversions between coordinate systems.

Installation

Add to your Gemfile:

gem 'os_national_grid'

Then install:

bundle install

Or install it manually:

gem install os_national_grid

Usage

Convert from OSGB36 (easting, northing) to WGS84 (longitude, latitude)

lng, lat = OsNationalGrid.os_ng_to_wgs84(481_987.066, 213_552.27)

=> [-0.812036, 51.814605]

Convert from WGS84 (longitude, latitude) to OSGB36 (easting, northing)

easting, northing = OsNationalGrid.wgs84_to_os_ng(-0.812036, 51.814605)

=> [481987.066, 213552.27]

Development

Run the test suite with:

bundle exec rake test

License

The gem is available as open source under the terms of the MIT License.