I have enabled latitude on my Android. On land it's accurate to 30-40m. However, I'm a coastguard volunteer and usually have my phone (in a pouch) in my pocket when on the water.
When I look at my latitude history, it sees me hovering around the coast. But rarely on the water. For example, I was at Calypso Bay, Motouihe a while back and latitude sees me on waiheke. Pineharbour sees me at Maraetai and the tow back from Calypso to Half moon bay sees a long line of marks along the eastern beach/bucklands beach coastline.
Has anyone else seen this. I know latitude is using GPS - but it sure aint plotting lat/long.