Navionics has Sonar Logging available now, here are a couple examples from the Navionics website. I did South Lindstrom this summer. Logged Sonar uploaded it Navionics and downloaded it my present chip via Freshest Data, this service is free and unlimited on how many times you upload and download data for the first year. Then after that it 99.00 charge per year. Your chip is never outdated.
So if you are running Humminbird and want to improve your lake detail for ice fishing check out Sonar Charts from Navionics. BTW this improved detail can be read on any sonar.
