Dynamic Lake Mapping Today

Over a decade ago, guides such as Brian "Bro" Brosdahl helped gather data and compile the first comprehensive high-definition digital maps of Minnesota for LakeMaster. Each day, his survey gear hummed along non-stop, logging many depths per second. Following his lake mapping runs, he learned countless new features of lakes he'd fished his entire life. "Way out in lake basins, I discovered little transitions in bottom content," he says. "These almost invisible areas would rise or drop a foot or less and often have small patches of hard or soft bottom. Sometimes, I'd find a little bed of mussels with fish around them. Other areas appeared to be tiny springs where groundwater percolated through the lakebed. Whenever I've gone back and checked them, they're holding fish."

The rising importance of digital lake maps is most evident in the many anglers who operate four or more separate 8- to 11-inch LCD sonar screens. On the console, a designated sonar unit often sits beside an LCD that runs maps full-time. Some anglers have a similar setup on the bow. It's become common for anglers to run units in full-screen map mode.

With larger screens, you can customize your views. On my Humminbird 1198c, I can call up a LakeMaster map and set it to occupy 60 percent of the screen, for example. In the remaining space, I can run sonar, side-imaging, 360-imaging, or stack two separate sonar views. It's also possible to preset frequently used screens for instant recall. A similar approach works with units from Garmin, Lowrance, and Raymarine, each offering different options, map sets, and features.

Cartography Today

For some anglers, digital lake mapping sometimes surpasses even sonar readings as the most referenced type of data. In freshwater, the major lake mapping companies — Humminbird, LakeMaster, Garmin, and Navionics — all offer awesome cartography products. Most of my experience lies with Humminbird's LakeMaster maps. In the mid 1990s, I recall being amazed by the radically detailed 1-foot contours on Gull Lake, Minnesota, for example — perhaps the first lake to reveal the complexity of its basin.

LakeMaster's most recent Minnesota SD card includes data on 2,200 lakes, including over 400 with 1-foot contours. LakeMaster digital GPS maps offer nationwide freshwater coverage, with SD cards for nine regions, including the Great Lakes, Southeast, and Western states. Its Lake of the Woods/Rainy Lake card has the most comprehensive coverage of these two border waters ever offered, thanks to thousands of hours of sounding by employees.

Humminbird LakeMaster technology offers interaction between lake mapping data and Minn Kota's iPilot Link boat control system. You can highlight specific depth ranges or automatically offset depth, relative to water level changes. A Minn Kota Terrova can move precisely along the specific contours shown on a LakeMaster map, a feature called "Follow The Contour." Humminbird's new ONIX touchscreens even allow anglers to program and operate the trolling motor through these screens. The company's AutoChart Live is a do-it-yourself mapping program that allows anglers to create their own high-definition maps in real-time, without additional processing.

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Navigation powerhouse Garmin also is breaking new ground. In-Fisherman TV boats are running Garmin GPSMAP and echoMAP units, each equipped with LakeVü HD Ultra cartography. Based on their own mapping, Garmin has coverage of more than 17,000 U.S. lakes, with 5,700 HD maps with 1-foot contours. Additional views, such as MarinerEye, provides a 3D representation of surrounding terrain above and below the waterline.

Currently, 40 U.S. waterbodies are mapped with Garmin's high-­resolution relief shading and satellite image overlays. The views afforded of these lakes are impressive, showing anglers a true 3D perspective, as if the lake had been drained. Among the MaxDef lakes are Clear Lake, California, Lake Havasu, Arizona, Lake Minnetonka, Minnesota, Lake of the Ozarks, Missouri-Arkansas, and Lake Cumberland, Kentucky.

Offering perhaps the broadest coverage of fresh and saltwater fisheries, Navionics HotMaps provide coverage of up to 18,000 lakes and over 2,500 high-definition lakes with 1-foot contours. They also offer a free year of downloadable chart updates with the purchase of many Navionics products. With multiple marine chart products, such as HotMaps, Gold and Platinum+, Navionics offers varying layers and dimensions of resolution. Satellite and 3D overlays are offered on Platinum+ charts, while Navionics+ maps provide a comprehensive collection of waterways with detailed contours.

Mobile apps from several companies allow instant connectivity between chartplotters and smartphones or tablets. Garmin's free Helm app lets users view and control Garmin GPSMAP 8000 series chartplotters from an iPhone or iPad. Boating USA is an app from Navionics that allows for planning and viewing Navionics charts. They also offer a free app that provides compatibility between a chartplotter screen and a wireless device.

Some mapping technologies are exclusive. New LakeMaster charts work only with Humminbird chartplotters, while Garmin LakeVü data run only on Garmin products. Navionics charts and software function with nearly all major brands, including Lowrance, Humminbird, Raymarine, Garmin, and Simrad.

Mapping Made Easy

One of the most useful new technologies is creating your own contour maps. While most major waterways are mapped, only rudimentary maps exist for small lakes, ponds, rivers, and remote Canadian lakes.

Navico-Lowrance's Insight Genesis offers a three-step process that involves first gathering depth and waypoint data. You then upload map data into a free Insight Genesis account, where the information is processed and compiled into a viewable map. Once approved, you can purchase an encrypted file that contains the data, which is compatible with Lowrance and Simrad chartplotters.

Humminbird's AutoChart Live, for exclusive use with ONIX and ION units, is a free download that allows you to survey, process, and view your own contour maps simultaneously. Like Insight Genesis, building maps with AutoChart Pro is a three-step process of record-process-export. But unlike Genesis AutoChart, the Humminbird system creates maps with included PC software that enables uploading to an online service. One feature of that system gathers and displays bottom hardness information onto newly created contour maps, in addition to a Side Imaging Mosaic that overlays side-imaging onto these maps.

AutoChart Live allows you to create maps while you fish. After an initial 8-hour mapping period expires, you can either erase the data and commence mapping or purchase a Zero Line Maps Card that provides shoreline boundaries for millions of worldwide waterbodies.

Imagine you're trolling along a point of an uncharted lake. AutoChart Live simultaneously gathers and displays new contour information, so your screen is updated with new depth and structure information. It's also possible to share new map data with friends who also run AutoChart. Or you can keep the maps to yourself, knowing you possess the most detailed lake map of that waterway.

Navionics' SonarCharts system stores sonar data from many brands of chartplotters and uses it to update inland and coastal cartography, adding about 2,000 updates daily. Users record on a Navionics card and download Freshest Data for their next outing. Moreover, using a Sonar Phone transducer and T Box from Vexilar, users can map waterways and immediately view maps created through WiFi on a Navionics app, on a smartphone or tablet.

Real-Time Lake Maps

Few anglers have more experience with AutoChart Live than Dr. Jason Halfen. A veteran tech consultant for companies including Rapala and Johnson Outdoors, Halfen runs The Technological Angler (­thetechnologicalangler.com), which specializes in teaching how to use marine technology to catch more and bigger fish.

He cites several examples from this past season where AutoChart Live yielded dramatic results. "Everyone lives near what I call backyard gems — overlooked and unmapped waterbodies. And even on surveyed lakes with 1-foot contours, such as the Mississippi River or Chippewa Flowage, Wisconsin, topography often changes."

He says that on the "Chip," submerged bogs are seasonal hotspots, but they move about, sinking to the bottom and rising to the surface depending on flow, weather, and other conditions. By periodically remapping productive areas, he's stayed ahead of the crowd, unearthing and focusing on these key structures that attract walleyes, panfish, and bass.

And on a small lake where a river frequently dumps silt and sand onto a shallow delta, Halfen says new channels and dunes frequently form. Besides being a navigational hazard, these dynamic structures attract gamefish. By running AutoChart Live over this delta, he updates maps to show the precise location of these little channels, hemmed in by shallow sand dunes. "The new map lets me focus on these cuts, where we've caught loads of walleyes, crappies, smallmouth bass, and big perch."

While surveying shoreline zones on another small lake, he discovered a line of stumps, submerged in 6 feet of water surrounded by 8-foot depths, 100 feet offshore. "I had this spot to myself and it yielded big sunfish and crappies, while anglers pounded the shorelines nearby."

Last fall, catfish guide Brad Durick virtually rediscovered the Red River of the North, building accurate contour maps no one else has access to. "Although I already knew the general topography of these areas, it's been amazing to chart the river and see its true features. No chart has ever been made of the Red, so you can imagine my excitement in owning this exclusive map."

I've been mapping portions of the Upper Mississippi River, which has also never been mapped in detail. The feeling you get while mapping virgin territory is unique, and there's potential for discovering hidden hot spots.

New-Age Lakescapes

Mapping technology is advancing so quickly that when walleye pro Bruce Samson (aka Doctor Sonar) showed me a new type of digital map, I could only shake my head. Samson, who's worked alongside GIS expert Warren Parsons for many years, has helped develop a growing series of maps that combine high-definition lake contours with satellite imagery.

Screen captures tell the story. Check the image of Bull Shoals Lake, for example. "These maps depict every submerged tree and their position relative to contours. Using maps of Bull Shoals and Table Rock, I've been able to troll crankbaits along the outer edges of these trees — where walleyes and bass feed and rarely snag."

Samson adds that his Devils Lake maps feature aerial imagery from 1949, well before the lake rose to its current level. These overlaid photos depict rockpiles, roadbeds, fencelines, and more. The same's true of his Lake Oahe map, which displays features from photos taken when water levels were low. On his map of Cass Lake, Minnesota, weedbeds are revealed, as well as rockpiles and the layout of sandbars and points. He now offers maps for over a dozen waterways. They're presently compatible only with Lowrance units (doctorsonar.com).

The future is now for aquatic maps. Consider that marine anglers already utilize satellite imagery that report surface water temperature, current, and plankton veils. But mysteries remain. As technology continues to shrink our perception of Planet Earth, fish somehow remain able to elude our hooks.