smo_os_bng_grids

https://github.com/Sebasmadridmx/smo_os_bng_grids

Developed by Sebastian Madrid Ontiveros. Pure Ruby gem providing all Ordnance Survey British National Grid squares (100km, 50km, 10km, 5km, 1km) with hardcoded geometry sourced directly from the OS BNG Grids GeoPackage. Supports point-to-grid-ref lookup by easting/northing, bounds retrieval, grid square validation, listing with filters, and export to ESRI Shapefile format. No external dependencies. Uses only Ruby stdlib. Contains OS data. Crown copyright and database right 2025. Licensed under the Open Government Licence v3.0. Built to support hydraulic modelling and flood risk workflows in the UK. If this gem saves you time, consider buying Sebastian a coffee at https://buymeacoffee.com/smadrid