so how do I know $189 will give me a good map of Lewisville?
Check out the Navionics Webapp online before you spend a dime. Be sure to toggle the button in the bottom left corner to turn on the sonar chart layer. The webapp is updated weekly, so this will show you the latest and greatest that Navionics has to offer. Navionics WebApp
My navionics app on my phone updated and showed a hump where my fish finder older app does not. I drove over to it and there was nothing there. It also messed up some other topography lines in certain areas as well. Has anyone else experienced this?