Base Location

Base Location. Compass allows you to enter a base location for a cave or cave system. The Base Location is used for calculating Magnetic Declination. It allows you make Magnetic Declination calculations even when you don't have any fixed stations associated with any of the surveys.

Here is an example of a Base Location in a Compass MAK file:

@398315.500,4483735.300,3048.000,13,0.780;

&North American 1983;

I. The '@' Parameter. This parameter indicates the base location of the cave. Since the value is only used to calculate Magnetic Declination, it does not have to be the entrance or specific location in the cave. All that is necessary is

Five values are specified in the command. Here is a description of each value in the order:

1. UTM East. The first value specifies the standard UTM-East distance in meters.

2. UTM North. This value specified the standard UTM-North distance in meters.

3. Elevation. This value specifies the elevation in meters.

4. Zone. This value specified the UTM zone number.

5. Convergence Angle. This value is the UTM convergence angle between the UTM grid and the line longitude.

II. The '&' Parameter. This parameter specifies the Datum used in geographic conversion operations. The Datum is specified as a string which must match exactly one of the Datums displayed in the Compass Geographic Calculator.