At the first corps, they gave us charts, and you wrote your dot down off the chart.
2nd corps we had charts and coordinate sheets, but after the drill was learned, no one really used either.
The best system I ever used was in high school with coordinate sheet only, and never dressing the form. No suprise that we learned drill faster and more accurately than either of those corps.
After using charts, I've learned to hate them with a passion. But even more, is I hate when dots are "sprayed" on the ground as you learn the drill, which both of my corps did. You never learn the exact spot you're supposed to go to, you just rely on muscle memory, which will vary as the course of the season goes on. I refused to let someone spray my dot on the ground, and I chose to memorize it instead.
I got sick of the heated arguments of me saying "I'm on my dot" and everyone else saying "get in the form". Even when we were "cleaning" drill, set by set. Charts yield little individual accountability.
Man, I'm looking forward to next summer.