The listerCompass is for geologists with an iPhone.
Designed by a structural geologist, it has been extensively tested in the field to see what is practical and what is not.
You can measure surfaces and lineations at the same time. The listerComnpass can also be held upside down, to measure foliations and lineations under overhangs.
To measure a foliation and a lineation simultaneously, orient the compass on the surface with the edge parallel to the lineation. For surfaces only place the compass parallel to the surface (any way you like).
Once the compass stabilizes, tap the screen to freeze the measurement. Double tap to record the data. If the error is too large, repeat the measurement.
Get it with iTunes http://www.apple.com/itunes/
There are numerous settings so you can make the compass work how you want it to work. Tap our double tap on the buttons to see how they change. Lock any preferred settings on the DataScreen.
Version 5.1 provides support for KML files - drop a pin on the map. The locations can be saved using the MapScreen, and the saved KML file can be dragged into Google Earth to display placemarks in standard format.