CaveDiveMap is an app designed for cave diving survey and automated mapping.

The app requires a 3d printed measuring wheel which is attached to a waterproof dive case for your iphone.
The app measures the rotations of the wheel using a small magnet mounted on the wheel.
The wheel is clamped to the guide line using the 3d printed adapter.

The app records automatic data points each rotation of the wheel, but also the diver sets manual station/anchor points at each tieoff before starting to the next.
The app requires the diver to perform quick on the fly calibration before saving the next data point to ensure maximum accuracy in heading with stationary magnet.

This method allows for quick, automated one handed surveying of sumps and underwater caves using the guide line.