3D Lake District lets you explore England's most popular mountain region on your phone or tablet with 1:25,000 Ordnance Survey OpenData maps.
The map data is downloaded when the app is first run (reliable WiFi connection recommended); subsequently no network connection is needed.
These maps are from Ordnance Survey, but they aren't the same as their paper maps. They include contour lines, rocks, roads, rivers, forest, coastline and urban features, and some footpaths are superimposed using data from OpenStreetMap. Please see the website for details.
The altitude data has a vertical resolution of 1m and a horizontal resolution of 50m, and is used to add a slope shading effect as well as the 3D landform.
Move around using one finger to drag the map, and the sliders at the edges of the screen to adjust your altitude and direction of view. You can zoom in and out with two fingers, but it's normally better to move closer to the ground rather than to zoom in in this way.
Important: Hardware Compatibility: 3D graphics hardware is needed. Works on the Samsung Galaxy Tab, Motorola Defy, and other devices with Imagination Technologies PowerVR SGX graphics (which should include most Motorola and Samsung phones). DOES NOT WORK on the Toshiba Folio 100 and other devices with NVidia Tegra graphics. Feedback about compatibility with other devices would be very much appreciated.
See also my national app, "UK Map 3D", which has less detailed 3D mapping for all of England, Scotland and Wales.