We’ve recently learned about the introduction of Humminbird’s Down Imaging for 2010, which will revolutionize the way we see objects that are directly beneath the boat. There are circumstances, however, when a traditional 2-D sonar view is just what an angler needs: identifying small schools of baitfish, finding the thermocline, and so forth.
In 2010, Humminbird brings its exclusive Switchfire technology to the 2-D sonar components of its industry-leading sonar/GPS combos, including the Side Imaging units in the 1100, 900, and 800 series (I’m checking now to see about the 700 series units). Here’s a bit about Switchfire, direct from Humminbird:
When you hit the water, you don’t limit yourself to one bait. So why limit your sonar? Exclusive Humminbird® SwitchFire™ Sonar gives you the power to choose how returns are displayed, so you can adjust with the fishing conditions—making our downlooking sonar an even more valuable fishfinding tool.
Max Mode: Watch as the sonar returns explode from the screen in amazing detail. You’ll see the tiniest subsurface object—even thermoclines and water currents—for complete underwater coverage.
Clear Mode: Time Variable Gain (TVG) software sifts through sonar returns to display only fish and structure. Great for fishing in shallow and rough water, or reducing undesired clutter in the water column.
A pair of screen captures, showing Switchfire in Max Mode (left) and Clear Mode (right) are included below.
Throw in an Ipilot, and you might just start to see white flags sticking up through the water surface! 
