Theodolite

This app was released back in 2009, but due to some big updates recently, we thought it was about time Tap! took to the hills to explore exactly what it can do with the latest iOS hardware.

A theodolite operates on measuring angles of horizontal and vertical planes, but this app is fully loaded with GPS and mapping features, so it’s more of a hiking app than a surveyor’s tool – although architects and engineers can still use it for more traditional purposes.

Theodolite overlays real-time information about your position, altitude, bearing, and horizontal/vertical inclination on the iPhone’s live camera image. It’s a real data feast and if you’re used to the kind of UI screen in astronomy apps, you’ll be comfortable with what’s being represented here. If not, you’ll need to acquaint yourself with the lingo, but what the app does so well is to name every area of instrumentation that you see. The text might be small, but it’s easy to read off and you won’t end up referring to the inbuilt manual to work out what the figures are. However, we recommend you take a look at the help menu to understand GPS coordinates, azimuth, bearing and elevation data properly.

The main viewer is neatly laid out allowing you to line up objects easily. You use the reticle to line up on the cross in the middle of the screen, and when it turns green you’ve got a good fix. If you want a seriously accurate measurement, you’ll need a tripod for your iPhone. Theodolite also lets you take geo-tagged camera images and movies that you can email to friends or colleagues. If you just wanted to capture location/measurement data as text you can also send that right from the main viewer, too.

The features go and on and on with Theodolite, and with camera filter options and the ability to add markers to maps (including a 20-person team view through an In-App Purchase), this could well be the only GPS assistant you need for outdoor pursuits.