Since 2010, Ordnance Survey have released a large amount of their map data under a free licence. The maps that this app uses are based on this data, and this is why the app can offer map downloads free of charge. Note that these are not the same as the paper Landranger® and Explorer® maps.
These maps are built in to the app and are always available. They are based on the OS MiniScale® and 1:250,000 scale colour raster products.
These maps are most suitable for countryside use. They are downloaded in 5km squares. Once they are downloaded they remain on your device until you delete them, so you don't need a network connection. They are based on the OS VectorMap™ District product, with contour lines from OS Terrain 50.
None of the free OS data released so far includes footpaths. Since footpaths are essential for countryside use, this app has superimposed footpaths derived from openstreetmap.org data. These paths have been recorded by volunteers; coverage is not yet complete and varies from place to place.
These maps are most suitable for urban use as they show most road names, building outlines and name important public buildings. Like the 1:25,000 maps they are downloaded in 5km squares and remain on your device until you choose to delete them. They are based on the OS Street View® product.
The OS OpenData licence allows commercial use of the data provided that the source of the data is acknowledged and the same rights and obligations are passed on to users of the derived product. Please see the licence for details.
The OpenStreetMap data is licensed under the Open Database License v1.0, under the terms of which these maps are a produced work. We would be happy to provide a copy of the derived database used in the production, or the algorithm used to create it, as required by section 4.6 of the licence; please contact us by email.
You are therefore free to use maps from this app (e.g. screenshots or similar) for any purpose, provided that you acknowledge Ordnance Survey and OpenStreetMap as the source of the maps and pass on the same terms.
For more information about the OS OpenData maps, see the OS OpenData website.