My 40-foot cast landed near the top of the offshore hump in around 14 feet of water. The descent of the gliding jig was intercepted by a feisty 18-inch Pymatuning walleye. During the next 15 minutes, five more walleyes met the same fate, all from an area not much bigger than my boat.

The area I was fishing features a mix of submerged reefs, some of which rise to within a few feet of the surface. While I’m familiar with the layout of the varied structure found there, it wasn’t until the past few weeks that I’ve been able to target specific spots with such accuracy. The change was brought about thanks to the release of a new mapping program from Garmin Marine, its Garmin Navionics Vision Plus product.

Maps that reveal the underwater secrets of lakes are a fundamental aspect of successful fishing. During my three-plus decades of serious fishing I’ve witnessed an interesting evolution in mapping. First came printed maps that provided rough contours of bottom layout. Fishing Hot Spots maps provided not only contours, but suggested areas to fish, tactics and background information on the lake. They continue to be useful tools.

Major changes came about when mapping products that work with GPS units came about. Third-party products such as those by Lake Master, Fishing Hot Spots, Navionics, and others, provided electronic contour maps for on-the-water use. A major step up, but there were compatibility issues between mapping products and GPS units, as well as variable accuracy. Also, the list of mapped lakes in our area tended to be short, as attention was given to regions/markets of the country with much larger waters.

More recently, anglers now can create their own contour maps. Garmin’s Quickdraw, Humminbird’s Auto Chart, Lowrance’s Genesis Live, allow users with chart-plotters that include such features, to make highly detailed maps for their own use. In some cases – such as with Garmin’s Quickdraw Community – users have the option of posting their maps to an online website to be shared with others.

Thanks to my own mapping efforts, and from those downloaded from Garmin’s map sharing site, I have detailed maps of all the local lakes such as Keystone, Yellow Creek, Glendale, Tionesta, Arthur, and others. Pymatuning however, posed an issue. Due to its immense size, mapping it isn’t practical. Of course, one could choose to map select areas. But this, too, can be a problem as boats are often sitting on the best areas, making it difficult to run the necessary swaths to create a contiguous map. And the built-in maps provided in my Garmin Echomap chart-plotters are decent for Pymatuning, but off enough to limit usefulness.

The Garmin/Navionics program released earlier this year combines Garmin mapping and Navionics (which Garmin purchased a few years ago) mapping. As I’ve hoped, the Pymatuning maps included in the Vision Plus cartography are outstanding. Not only are the contours detailed and highly accurate, but include a layer called Relief Shading. This feature gives the map a three-dimensional look like that now commonly included on topographical maps. The relief shading layer is currently available, in our area, on Pymatuning, Raystown, Wallenpaupack, Chautauqua and Lake Erie (including Presque Isle Bay).

Garmin’s Vision Plus (as well as the lesser-priced Vision, which has fewer features) only works on select Garmin chart-plotters. The initial investment includes a one-year subscription for map updates. More information on the product can be obtained by visiting www.garmin.com.

Jeff Knapp is an outdoors columnist for the Butler Eagle.