The autochart live in the Helix units with the use of a zero line card allows you to create your own depth profile map but you will only be able to see it on your Helix unit. Autochart Pro allows you to pull the recorded data up on your PC and study the map, highlight depths, bottom hardness, and integrate the SI mosaics into your contour maps. Being able to sit down at my desk, review the maps, and actually play back the Si recordings a day, a week, a month, or a year later to find the structure I am looking for without having to sit looking at my Helix and playing with the multidirectional button on the Helix is what I like most about the Autochart software. The Autochart also allows me to mark waypoints on the contour map I have created of structure I want to go back and fish and also create track lines that I want to follow using my i-pilot link next time I am out trolling on that lake. The difference between Autochart and Autochart Pro is that Autochart pro allows me to view bottom hardness and the SI mosaics where Autochart doesn't. Additionally, once I have processed and integrated the data on a lake from multiple trips and cleaned it up, I can save it to a second zero line card for a buddy to use if I want and he can view the updated maps on any HB unit that can view Lake Master maps not just a Helix 9, 10 or 12. Not sure if I explained all of that very well, but hopefully it will help you decide if Autochart or Autochart Pro is something you want to mess with.