Grid Ref is a simple iPhone™ / iPod™ touch app that displays your current position as a grid reference, as used on Ordnance Survey maps. Other apps show your position using only latitude and longitude which is not very useful for O.S. map users, since these maps show only the O.S. grid.
Accuracy will be as good as the hardware can provide, i.e. to within a few metres using the iPhone 3G's GPS. The iPod touch seems to manage a resolution of a hundred metres or so in built-up areas, but is useless in the countryside. Grid Ref reports the hardware's estimate of its current accuracy and also shows your altitude if the hardware knows it.
Grid Ref is available from Apple™'s App Store in the Navigation category for only 59p.
Feedback and questions are welcome.
Please also have a look at another of my iPhone apps, the Panoramascope, which computes and displays the skyline as seen from almost anywhere in the world.
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