Regardless of the species of fish you’re after and type of boat you run, maps are a worthwhile investment for improved boating accuracy and for minimizing the risk of accidently running too shallow or hitting something you didn’t know was there.
March 06, 2025
By Thomas Allen
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To me, lake contour mapping is the single greatest advancement in fishing technology. Sure, forward-facing sonar has changed the game, but you still need to know where to start and what depths and structures fish are relating to. Gone are the days of triangulating a weededge or rockpile. The ability to place waypoints along structure and depth contours is invaluable to catching more fish.
Regardless of the brand of mapping you use, a variety of applications therein increase angler productivity. The ability to get the most out of your mapping data starts with unit navigation and on-the-water functionality. And time on the water is the single best way to learn how it all works.
Several mapping programs are available to anglers, depending on the brand of electronics. Some mapping systems work across brands, while others are exclusive to the company with which they’re affiliated. LakeMaster is from Humminbird , C-Map is unique to Lowrance , and Garmin recently acquired Navionics , but they also have an extensive library of their own unique maps.
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On some bodies of water, one brand’s map might be best, while other lakes are better represented with another brand of maps. For what’s best on your particular lake, consult with local anglers or keep multiple map cards handy to test.
Adding depth contour color shading helps certain structural elements become more obvious. Shading different depths with different colors help you establish patterns, and also increases awareness of hazards. Depth Contour Shading One of the most valuable features within your unit’s mapping programs is the ability to shade different depth ranges with different colors, which helps you quickly visualize similar depth areas, especially shallow areas and breaklines, and also helps you identify other likely fish-holding structure. Depth shading also helps you quickly identify and avoid hazards while boating from spot to spot.
With LakeMaster, you can set the shallow-water depth range with the color red to show potentially dangerous areas to be aware of when running the boat. You can also highlight depth ranges that have been holding fish, or perhaps not holding fish.
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The visual contrast is valuable, not only for making quicker and safer decisions, but it also can highlight deeper structure that you may not have otherwise noticed. On lakes where 1-foot contours are available, you can set the contrast by the foot—making the feature highly customizable. LakeMaster’s new VX cards offer even more contour shading, among other improved features.
Many of our nation’s fisheries are impoundments that are subject to water-level fluctuations, sometimes at a rapid rate, so making quick water-level adjustments on your map is often helpful and necessary. Humminbird’s Water Level Offset, Garmin’s Lake Level Offset, and Lowrance’s C-Map Lake Level Offset allow you to enter the current water level, and the entire lake map adjusts accordingly—a strong application to seasonal usage.
Looking at different types of information at the same time is critical to the process. Cross-referencing between your map, 2D sonar, and side- and down-scanning helps you verify what you’re seeing. Comparative Scanning Viewing multiple screens that deliver different types of information simultaneously is a practice we’ve discussed at length in this column. Comparative scanning helps you become confident with each technology and helps put the overall puzzle together. Looking at sonar while keeping an eye on your map, for instance, helps you cross reference what you’re seeing.
Regularly swap views on your graphs to verify what you’re looking at. As you find likely structure or other spots of interest, drop a waypoint and return to fish that area. I suggest keeping the full-screen chart or map as your top favorite. After you’ve created a series of productive waypoints, you’ll begin to find similarities in depths and contours where fishing is productive—and that’s the start of your pattern algorithm.
Humminbird offers LakeMaster SmartStrike map cards that allow you to build your own algorithm search requests based on the information you input into the unit. With SmartStrike, you enter search parameters and you can highlight areas on the lake map that meet specific criteria for depth, slope, and other parameters. The program also comes standard on the new LakeMaster VX Premium cards . It takes a bit of time on the water to really build it out, but it certainly helps to isolate the best water—and it’s accurate. Put as much if not more time scouting as fishing, and you will certainly catch more fish.
Casting rings are also helpful when to return to a waypoint and begin fishing. Lowrance calls them Range Rings, Humminbird calls them Casting Rings, and to Garmin it’s Heading Line, all of which allow you to place a ring around waypoints. The concept helps you customize the distance between the outer edge of the ring, so you know exactly how far you are from the spot (waypoint) you want to cast to. It’s wise when building a pattern to keep your distance so you don’t spook the fish you’re trying to catch.
How you arrange different views on your graph is personal preference. A horizontal split, for example, between Chart and Side Imaging allows you to get the most out of the two technologies at the same time. Waypoint and Track Management Tracks are as important as waypoints, especially when navigating complicated and potentially dangerous waters. But some graphs can only store a limited number of tracks. I like to save them, and that might take some investigating on the step-by-step process by brand. Each season, I back up all my tracks and waypoints to an SD card and then transfer them to a hard drive as a backup.
I don’t recommend saving every waypoint on one unit. Any electronics and mapping system that shares data through networking allows you to share waypoints from graph to graph. If I create a waypoint on one of my dash units, for example, it’s saved on that unit specifically but shares the waypoint to all units when everything is turned on. But too many waypoints can slow your units down, so remember you can save waypoints on separate units as they can be shared across the network. On occasion, it’s a good idea to go back and delete unwanted waypoints—a good practice to ensure unit health and lifespan.
Most units also allow for waypoint customization, like unique names, colors, or markers that indicate a brushpiles, rocks, weeds, docks, and more.
We fish all over the country for In-Fisherman TV and we have a lot of data to manage. I suggest creating a map card storage box and keep a few extra blank cards handy to not only back up your waypoints and tracks, but also to take screenshots of what you’re looking at—irreplaceable information to study later. I keep both a traditional-sized SD card and a micro card handy, as Humminbird’s Helix takes the larger ones and the Solix requires micros—an easy situation to deal with. Making Your Own Maps Each brand allows the user to generate their own maps. Garmin calls it QuickDraw, Humminbird has AutoChart Live , and with Lowrance the process is within the C-Map Genesis program. Each program helps you create a detailed depth-contour to overlay onto your existing maps. Not all lake maps are created equal, especially when dealing with a water body that hasn’t been scanned as thoroughly as one might prefer, so you can make your own. This can be a time-consuming process, and you’ll need to go back and forth and criss-cross the area you’re mapping to maximize data and accuracy, but it’s worth it.
Map data take up storage so make sure you have a data backup plan. Humminbird offers a Zero Lines card that allow you to store gigs of map data—you’re not likely to fill the card. Take advantage of the customization opportunities and keep everything backed up.
When creating my own maps, I’ve found interesting features that weren’t on the original maps. The power of creating your own map is hard to beat. It takes getting used to, and it’s kind of like mowing a lawn—you go back and forth until the contours start to come together. Experiment; it’s a lot of fun. The Modern Map Regardless of the species of fish you’re after and type of boat you run, maps are a worthwhile investment for improved boating accuracy and for minimizing the risk of accidently running too shallow or hitting something you didn’t know was there.
The value for anglers is seeing the layout details of the waterbody at a glance—depths, dropoffs, points, humps, flats, waypoints, tracks, and much more, in addition to features you can add by doing your own mapping. In the end, you’ll have more productive trips with more fish the boat.
