Hey guys,
Check out the new feature from Navionics called Sonarchart Shading.. This feature will soon be available on the Platinum+ and Hotmaps Platinum mapping cards either on a new card purchase or with a simple update to your existing card. The feature uses the 1� high definition depth contours known as the Sonarchart layer, combined with aerial overlay information to shade depth changes to help in locating breaks, drains and channels a lot quicker, making you time on the water a lot more efficient. For more info check out the link below:

Navionics Sonarchart Shading