Wow. I just found an online way to look at nearly all depth maps in the BW. It is free and seems very accurate. It is the "Chartviewer" on the Navionics site.

Navionics

I checked a few lakes and it seems pretty amazing.

If you switch between the navionics and sonar chart options, it looks even more amazing.

Here is the section of Clearwater lake that is being discussed in another thread.

Sweet. More important is time spent fishing. That will never change. I’ve always brought contour maps, but in reality, I rarely use them once I’m out there. Fishing usually catches fish, not staring at a color coded contour map in camp. The eyes on the water will tell you more than the eyes on a map. Fishing out of a canoe is different than fishing out of a rigged boat. That is a consideration.

I have the navionics app on my phone. It works great.

I have to agree this is a cool site. I have the Navionics plus chip for my depth finder. It covers most lakes in the USA and Canada.

The cool thing is you go over an area with your depth finder with the Navionics chip in it. Then the next time you hook up to your computer you download the sonar information you charted for others to now use. And you upload new sonar chart information for you to use. So everyone is constantly updating the sonar charts.

I uploaded most of my possible lakes I will fish with the newest sonar charts, about 1/2 of Minnesota and 1/4 of Ontario.

I've noticed the depths on Knife Lake are about 10-15 feet too deep. Notice how some of the sunken islands are no longer sunken. It would be nice to add Ottertrack to the list of lakes that have been sounded.

I bought a smaller tablet used for $40 and spent another $30 on the Navionics app. Had it out on the ice the other day and caught a couple of lake trout on a little 40' shelf. Pretty sweet. Most of the contour lines are ten foot, so it is more useful in deeper lakes, but definitely a tool worth having on the belt. I'm looking forward to using it in the canoe.

MrBadExample: "I have the navionics app on my phone. It works great."

Me too. If you save the map on the app you can view it in the BWCA. In Airplane Mode on my iPhone I can see my position, speed, etc. live on the contour map.

It appears that Navionics starts their map data for a BWCA lake based on the heavily generalized MNDNR contours available online. As someone said, this data is then updated when someone with a Navionics chip in their fish finder paddles over certain areas in a path, records actual depth and contour information, then downloads it to the Navionics site. Be aware that the contours on their site are a mixture of this information and should be taken with a grain of salt. On a certain lake, I can clearly see midlake humps from Google Earth that are indicated as being a 25 foot deep basin.

Although the contour data is somewhat helpful, there is still no substitute for actual on the water investigation with your own equipment.

SE

navionics is a good option but nothing beats charting your own maps. this way, it ensures that they are accurate
We were out last month on tonka trying to find a 8' hump that literally doesnt exist anymore, but on navionics it says it is there.

I use Navionics as a reference but find that it can be off by quite a bit. Sometimes it seems like it is shifted and not quite synced with the gps and other times it seems like the depths are just plain wrong. When I'm on a new lake its nice to have to get some ideas of where to start though.

I'm getting the itch for my May trip. I spent a while looking at these maps and gameplanning...