3.4. Measuring range and bearing
3.4.1. Range & Bearing
It's worth reminding you at this point about the Range Bearing measuring tool 
which is frequently useful in analysis. The calculated range and bearing is displayed at the bottom right-hand corner of the Tote.
The default units for the range displayed is configured using the Properties File (d2ksettings.prp), but it can be over-ridden by double-clicking on the calculated range/bearing data itself. A property editor will open, from which you can switch to one of the following units:
| yds | Yards | |
| nm | Nautical Miles | |
| km | Kilometres | |
| m | Metres |
3.4.2. Earth Model
The Range Bearing calculation is performed using the algorithms in the current Earth Model
The Earth Model used by the application is modular and interchangeable. In the initial release of the application the calculations use the Rhumb-Line Formulae for Short-distance sailing, as described in "Admiralty Manual of Navigation, Volume 2, 1973". Short-distance sailing is defined as "the following of a rhumb-line track for a distance not greater than 600' ".