What is the Purpose of a Control File

[hlb2]

Only been using for a month, but I've seen this option, but it's not explained very well. I read some posts on here, but I can't wrap my head around this concept. What purpose does this serve? Sorry to be so naive but I've never heard of this.

[RSCARON]

SAY YOU DID A JOB , HAD A BALANCED TRAVERSE,CONTROL POINTS AND BOUNDARY POINTS. SAY 1-15 TRAVERSE, 100-142 BOUNDARY POINTS AND A COUPLE OF SPUR POINTS 50&51

WEEKS LATER YOU WANT TO DO SOME TOPO, LOCATE A FOUNDATION OR ANYTHING ELSE. --YOU MAKE A NEW JOB , FIND YOUR JOB THAT HAS ALL YOUR CONTROL POINTS IN IT.
WHEN YOU SET UP IF THAT POINT EXISTS IN THE CONTROL JOB IT WILL USE THOSE COORDINATES SO INSTRUMENT SET UP ON 50 BACK SIGHT 4 THOSE POINTS WILL BE RELATIVE TO WHAT YOU DID PREVIOUSLY.

IN CARLSON YOU CAN DUPLICATE POINTS SO YOU MUST BE CARFUL

ALSO IF YOU RETURN TO A SITE FREQUENTLY AND MUST SET UP ON A CERTAIN POINT THAT YOU MAY HAVE CREATED IN THE PAST, BUT YOU WERE GIVEN POINTS FROM SOMEONE ELSE WHO DIDNT GIVE YOU THE POINT YOU NEED. --- YOU CAN IF YOU STILL HAVE THE JOB IN THE COLLECTOR MAKE THAT OLDER JOB A CONTROL JOB AND BRING IT IN TO THE NEW ONE.

WE HAVE DONE SURVEYS NEXT DOOR TO A OLDER JOB AND USE THIS METHOD FREQUENTLY TO TIE THE JOBS TOGETHER WITHOUT HAVING TO COMP OUT ENTIRE BLOCK AGAIN