G. H. I.
J. K. L.
A. Walled Lake is a small natural lake in Michigan, with clear water and shallow weedbeds. The shallower zones and
weeds are partially visible via Google Earth. B. The zigzag method of charting a lake ensures full coverage of every con-
tour and detail. C. The resulting contour map. The darker the blue, the deeper the water. D. Close-ups of the 1-foot
contours on the map. E. The bottom hardness map shows the areas with hardest bottom in dark orange, areas that
transition from hard to soft in lighter