NOAA Office of Coast Survey. Go to this website and you will find several charts. #14830 is the westend. You can also buy one of the Hot Spot charts and some numbers for gps such a bouys, lighthouses, reefs and channels will be listed. Look at how the Lat and Long numbers are on the chart. So if you hear that I am fishing at 48 and 00. Thats 48 north and 00 west, and thats a few miles due north of " C can". These are the middle numbers on GPS. You can also hear maybe 34 and 17. Is this for sure in the west end of the lake ? No, its actually north of Vermilion near the sandbar. The more you study a good chart and all the info and landmarks, the better the GPS numbers are to figure out a location.