Hey Bruce ...
If you mean a number like this: N58 10.56 / W134 33.75 - 024*
There are two such columns. The first column locates the structure exactly. That is Latitude, Longitude and Altitude.
The second column is the "mooring point" or "starting Point". That is the latitude and longitude and MAGNETIC HEADING you use to put yourself in a start position at that location.
You would normally be using the second column. Lets say you wanted to start at Admiralty Cove Cabin
Look at the second column and you will see: N58 10.56 / W134 33.75 - 024*
The first set N58 10.56 is the latitude
The second set W132 33.75 is the longitude
The third number 024 is the Magnetic heading.
To place yourself exactly at the starting point, you bring up "MAP" in you sim. Once it comes up, put the Latitude, Longitude and Heading into the table. Always set the altitude to ZERO and the Speed to ZERO.
When you click OK, you will find yourself at the dock at the Admiralty Cove Cabin.
Let me know if this helps.
Doug