Depending on if you had a laptop in the boat or not, easy or easier. First if your using a Lowrance unit that uses the cards you can store the data in an SLG file as you go along then put it on a card and make a map several ways. Right here I want to say DrDepth is so easy. In the program is a function that will take will convert an SLG file to a DrDepth format data. Then all you have to do is open it. It doesn't automatically open it cause you might want to do more than one at a time.
Once you have load it the choice's are, do you want a 2D map, a 3D map or export it as a shape file (SHP). If your using Lowrance's you can take that SHP file and convert it back to a Lowrance format that will run on a chip like a commercial map, pop it in and go. I just wish we could do that with the Humminbird's.
If you want to do more than just make a paper map you have two choices, one you can run them in a program like Fugawi that'll take the map and give you coordinates any where on the map or do like many of us like Bruce Samson does, www.hightechfishing.com , and run it on a laptop in the boat where it'll show you any where on the map as you go.
If you go the laptop route, you can just reload the data every time in DrDepth and make a map so you can see your position as you go. Fun part of this, as long as the water level doesn't change I have it hooked to the sonar getting data and as you go along it just keeps making a better map. I did when I was doing that 3D map of Clearwater. I enjoy working with Doc and Per so I put a banner down on left side. Next to it you can open the Clearwater 3D. It created the map on the fly as I drove around on the lake so if there was some thing extra interesting I just looped back over it. You can also see the area in the NW corner where I had to stop going further across the lake cause of the waves. Next time out all I have to do is rerun the map and I can see where I need to fill in and watch as I do.
Thats where the Humminbird 997 really made it great. As I ran on the grid lines in DrDepth I could see if I was missing any thing in between. I just really really wish I could make the contour maps like we do for the Lowrance's, but I wouldn't trade it for any thing now.

WarrenMN