Just picked up a Helix 7 w/SI, DI and GPS.  Some of the lakes I fish have old/inaccurate contour maps so I bought Humminbirds Zero Lines Autochart (micro card).  Has anyone out there been using this? If so, what's your take on it? Is it complicated to make maps? Once I have run transects in both directions, how do get it to create contours and a contour map. Do I need some additional software to create the finished map? Looking for other folks experience and advice.