Links and Fixed Stations.

Compass has a very powerful feature that allows you to control the way in which survey files are connected together and the way they are connected to the outside world. This feature is used in two ways:

1. Preventing Station Name Conflicts. In some instances, you will be combining survey files where there are duplicate station names. For example, you might be combining two caves that both have an "AB" survey. This would probably mean that two different stations would have the same name. Having duplicate names in different caves would confuse the program. (It will assume that the first station it sees is the basic location of the station and the other locations are large closure errors.) This will cause long, erroneous lines to be drawn between the two caves.

Linking allows you to combine survey files that have duplicate station names. With linking, you tell the compiler which stations are to be used to connect two cave files together. Linking tells the compiler to remember only the linking stations and forget all other stations between files. This way, duplicate station names do not interfere with each other.

Linking is only necessary when you have duplicate station names. As long as there are no duplicate station names, you can ignore linking.

Linking also effects the way the Loop Closer processes files. Click here for detailed information on how linking effects the Loop Closer.

2. Fixed Stations. Compass also allows you to tie individual stations in the cave to fixed geographic locations in the outside world. For example, you can tie stations benchmarks, surveyor’s grids, topo maps, and other outside references together. This has the effect of making all the locations in the cave relative to the real world. For example, if the entrance station of a cave is tied to a GPS receiver fix, then all the stations in the cave will have their actual elevation above sea level.

Click here for complete information about creating and using links.