[Therion] How to combine two maps

[Bill Gee]

Hello everyone -

I am sure someone has come across this problem.  I looked all through the 
Therion Book and the online Wiki, but did not find anything that looked 
useful.

We've been surveying a cave for several years now.  It is a tough cave.  The 
map is now a bit over 10,700 feet (3,261 meters).  There are several nearby 
caves that have been getting mapped as time permits.  They have been treated 
as separate projects, each with their own map.

Last weekend a human-passable connection was discovered between the big cave 
and one of the nearby caves.  It is only for small humans, but it has been 
traversed.  The centerline survey should be done the next time we go out 
there.  It will only take a few more stations to survey the connection.

First question:  Is there a way to combine the two maps so that Therion treats 
them as a single map?  I don't want to have to redraw over 300 meters of cave!  
I suppose I could simply add the th2 files of one cave to the other.  Is that 
the usual method?

Second question:  We have GPS coordinates of the two entrances.  Is it 
possible to specify both sets in the centerline data?

Third question:  As I said, there are several smaller caves nearby.  It would 
be useful to have them all displayed on the same printout.  Is there a way to 
tell Therion to import a map and place it on the drawing using GPS coordinates 
to maintain scale distance?

Thanks!

-- 
Bill Gee