Garmin Map Page...COG? SOG?

[Kymasabe]

I have a Garmin 498 GPS/fishfinder combo and my most used page is my map page or map/fishfinder split. I'll be playing with the 498 this weekend to see if I can get depth on my map page without have to split and use the sonar page at the same time.
My big question is...some of the other info on the map page is COG and SOG and I can't find anything in the owners manual that tells me what those mean?
Anyone help before I call Garmin and make a fool of myself?

 

[BillP]

Re: Garmin Map Page...COG? SOG?

COG = course over ground
SOG = speed over ground

COG is easy to figure but what is SOG used for? The boat speedometer shows 6 knots but the SOG shows 3 knots. It means you are in a 3 knot current. I use SOG mostly when trolling offshore in the gulfstream. It takes a short time to troll north and a lot longer to troll the same distance south. We cover a lot more fishing ground going north.