Home Natural Resource Management Bringing lake-bottoms to maps

Bringing lake-bottoms to maps

At last, Mike Wood has sated his dual obsessions for mapmaking and fishing. Now watch as LakeMaster, his company in Little Falls, Minn., begins to blow the lid off of Minnesota’s deepest fishing secrets.

Wood and his colleagues are in the process of remapping the 100 most popular Minnesota fishing lakes, using state-of-the-art computer and GPS technology. They’ve already knocked off more than 50 lakes, and their maps show volumes of structural detail that never appear on maps produced by the Department of Natural Resources (DNR).

Those details include fish-holding underwater humps, drop offs and rock piles that were known only to local guides, who tried to keep them a blood secret. In his quest to reveal the exact formation of Minnesota’s lake bottoms, Wood is pushing a common but inexact tool, the lake map, into new technological territory.

For years, anglers have relied on the DNR’s surveyed lake maps, which have been tweaked and reproduced by numerous companies for resale, either as plastic cards or in books. The problem was that the DNR maps, which go back to the 1930s, were produced using crude methods by today’s standards. Some early mapping efforts involved dropping a weighted rope through the ice and following a transect, or straight line, across the lake.

More recently, biologists have used boats and sonar equipment while criss-crossing the lake in straight lines and recording the depth changes as curvy contour lines on maps.

Wood and other savvy anglers have known that the maps offered limited information, and those limitations have become more obvious with advances in GPS. Wood and his six employees work out of a storefront in downtown Little Falls. When they’re not crunching data on computers, they’re in boats during the open-water season, surveying lakes.

“The computer on board is the heart of our system,” Wood said. “It collects data from the GPS, the exact positions of the boat, and merges those points with each sounding ping from our transducers.” Transducers collect and send sonar signals.

Wood’s maps show changes in depths in three-foot increments, although the Mille Lacs map is in one-foot increments. Most DNR maps show depth changes in five- or even 10-foot increments.

Besides being more detailed, Wood’s maps have the added advantage of being GPS accurate. It’s this technology that advances the common lake map into a new arena of fishing technology.

LakeMaster maps currently are available as traditional paper maps, as software that can be loaded into a home computer and as a computer chip that can be installed directly into a GPS unit.