Distance units may be Miles, Kilometers, or Chains. (A chain is 100 feet.) This option behaves differently from the others. If you change it, and track locations are represented as scaled values, the displayed location of the profile will not change. The reason is that Rangecam does not assume any particular unit of distance measurement, and relies on you, the user, to tell it how to interpret location values. This ultimately depends on how the data was collected in the field. If the Field System odometer was set to Km. when the data was collected, the Office System Distance Units option must be set accordingly! This is reasonable, as the reference markers in the field are in fact mileposts, or kilometer boards, or engineering stations (every 100 feet.)
If track locations are represented as reference plus distance, the distance units setting does affect the location display. Rangecam converts the fractional distance from the reference point to minor units: miles or chains to feet, kilometers to meters.
The Distance Units option is also different from the others in that the parameter value is stored in the database. Normally, you will set the Distance Units option when you first set up a database, and never touch it again.
The Distance Units option also affects several reports, notably the Inventory Report. If you erroneously tell the system that its distance units are chains when in fact they are miles, rail inventory will be under-reported by 5280 / 100 = 52.8 times! To avoid such problems, make sure that the Field System odometer is set to the correct units before data is collected, and that it is correctly set in the Office System database when data is read in.