https://github.com/defra/os-map-ref
OsMapRef is a tool to help handle UK Ordnance Survey map references, in particular to convert them to other coordinate systems
https://github.com/defra/os-map-ref
Last synced: about 1 year ago
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OsMapRef is a tool to help handle UK Ordnance Survey map references, in particular to convert them to other coordinate systems
- Host: GitHub
- URL: https://github.com/defra/os-map-ref
- Owner: DEFRA
- License: other
- Created: 2016-03-23T09:08:48.000Z (about 10 years ago)
- Default Branch: main
- Last Pushed: 2022-05-06T07:50:05.000Z (about 4 years ago)
- Last Synced: 2024-04-25T07:43:03.453Z (about 2 years ago)
- Language: Ruby
- Homepage:
- Size: 82 KB
- Stars: 2
- Watchers: 12
- Forks: 5
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# OsMapRef
[](https://sonarcloud.io/dashboard?id=DEFRA_os-map-ref)
[](https://sonarcloud.io/dashboard?id=DEFRA_os-map-ref)
[](https://badge.fury.io/rb/os_map_ref)
[](http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3)
This gem allows you to gather U.K. Ordnance Survey Eastings, North, and Map
References from a range of text inputs.
## Installation
Add this line to your application's Gemfile
```ruby
gem 'os_map_ref'
```
And then update your dependencies by calling
```bash
$ bundle install
```
Or install it yourself as
```bash
$ gem install os_map_ref
```
## Usage
To convert a map reference to eastings and northings
```ruby
location = OsMapRef::Location.for 'ST5880171043'
location.easting == 358801
location.northing == 171043
location.map_reference == 'ST 58801 71043'
```
To convert eastings and northings to a map reference
```ruby
location = OsMapRef::Location.for '358801, 171043'
location.easting == 358801
location.northing == 171043
location.map_reference == 'ST 58801 71043'
```
### Handling short easting/northing input values
If the full input easting or northing value has fewer than six digits, for example a northing value for a location in the south of England, the input value should be left-zero-padded within the input string. For example:
*Without* a leading zero on the northing input value, the map reference is for a location in Fife, Scotland:
```ruby
location = OsMapRef::Location.for '358801, 71043'
location.easting == 358801
location.northing == 710430
location.map_reference == 'NO 58801 10430'
```
Whereas *with* a leading zero on the northing input value, the map reference is for a location in Dorset, England.
```ruby
location = OsMapRef::Location.for '358801, 071043'
location.easting == 358801
location.northing == 071043
location.map_reference == 'SY 58801 71043'
```
### From OS Map Reference to Longitude and Latitude
If your end result needs to be longitude and latitude, you can combine the
OsMapRef output with that of another gem called
[global_convert](https://github.com/reggieb/global_convert)
For example
```ruby
require 'global_convert'
require 'os_map_ref'
os_location = OsMapRef::Location.for 'ST 58801 71043'
location = GlobalConvert::Location.new(
input: {
projection: :osgb36,
lon: os_location.easting,
lat: os_location.northing
},
output: {
projection: :wgs84
}
)
puts "Latitude = #{location.lat} in radians."
puts "Longitude = #{location.lon} in radians."
```
## Development
After checking out the repo, run `bin/setup` to install dependencies. Then, run `bundle exec rake` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run `bundle exec rake install`.
## Contributing to this project
If you have an idea you'd like to contribute please log an issue.
All contributions should be submitted via a pull request.
## License
THIS INFORMATION IS LICENSED UNDER THE CONDITIONS OF THE OPEN GOVERNMENT LICENCE found at:
http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3
The following attribution statement MUST be cited in your products and applications when using this information.
> Contains public sector information licensed under the Open Government license v3
### About the license
The Open Government Licence (OGL) was developed by the Controller of Her Majesty's Stationery Office (HMSO) to enable information providers in the public sector to license the use and re-use of their information under a common open licence.
It is designed to encourage use and re-use of information freely and flexibly, with only a few conditions.