This gem allows you to gather U.K. Ordnance Survey Eastings, North, and Map References from a range of text inputs.

Add this line to your application's Gemfile:

gem 'os_map_ref'

And then execute:

$ bundle

Or install it yourself as:

$ gem install os_map_ref

To convert a map reference to eastings and northings:

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:

location = OsMapRef::Location.for '358801, 171043'

location.easting       == 358801
location.northing      == 171043
location.map_reference == 'ST 58801 71043'

If your end result needs to be longitude and latitude, you can combine the OsMapRef output with that of another gem: global_convert

For example

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."

After checking out the repo, run bin/setup to install dependencies. Then, run rake test 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.

Bug reports and pull requests are welcome on GitHub at https://github.com/reggieb/os_map_ref.