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