Topographic Maps…

I am doing a school project and I am wondering how topographic maps are made…I know Lakemaster is a site sponsor, Maybe a representative from there could explain in detail how exactly they get such presise depth ranges for all the lakes and rivers…I know a method, where you can use a grid system and lengths of string to measure depths through strategically driled ice holes, but obviously this method cannot be used to make large topo maps of a variety of areas..thats just simply too time consuming…So can somebody let me in on the secret…how is it done?

Thanks,
Cade

I believe the hire BrianK to go out trolling… and every snag he gets, they reduce the depth on the map

Just kidding..> I have no idea.

I could be wrong on this but I seem to remember a story on Back Roads or MN Bound w/Ron Schara where a boat is rigged with, for a lack of better words, out riggers. A series of GPS/depth finders along each out rigger record the depth at the specific location as the boat drives a parallel back and forth across the lake.

Does this seem to ring a bell with anyone?

I think is how it is done too. Thats why the lakes take awhile to get the 1 foot contours constructed.

Cade,
I am not sure of the exact method but last summer I was out on Castle-Rock lake. There was a DNR Pontoon boat on the lake. The guy driving the boat kept going back and forth between the river channel and the shore. He had a series of computers on the deck of the boat. Later that day I ran into him at the boat launch and asked him what he was doing. He told me that he was updating the lake contours for mapping purposes.

Cade:

I have some experience with this. I’ll shoot you a pm.