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Changes for version 2.12

  • Re-worked the handling of points near the boundary of the OSTN02 polygon, to avoid a potential loop in rare cases. This is unlikely to affect any transformations with real coordinates (unless you spend a lot of time in boats about 10km offshore), but avoids some problems in my testing with random grid points.
  • Simplified OSTN02 data access. Removed the OSGM02 height part of the data as this is no longer used. This makes the module somewhat smaller and a little faster to load.
  • Added user interface to approximate conversion routines for quick Helmert transformations: "grid_to_ll_helmert" and "ll_to_grid_helmert"
  • Fixed a small bug in "parse_grid", so that it allows '/' character in map sheet names, and therefore works with sheet names like: 'B:110/OL44'
  • Corrected structure of POD documentation in Maps.pm and Background.pm
  • Simplified testing of random grid references to give more reliable results. Added more tests based on OS transformations, and to prove some edge conditions.

Documentation

Backround and extended description

Modules

Convert coordinates between Lat/Lon and the British National Grid
Format and parse British National Grid references
Data for OSGB Maps