Lake Maps on Fish Finders: Navionics, Garmin LakeVü, C-MAP, Humminbird LakeMaster and Making Your Own
A detailed contour map shows you points, humps and channels before you ever turn on the sonar. Here is how the main chart options compare and how to map a lake yourself.
The best lake map for you is usually the one built for your brand of fish finder that covers your home waters in detail. Garmin units use Garmin charts, including LakeVü and Navionics (Garmin has owned Navionics since 2017). Humminbird uses LakeMaster. Lowrance uses C-MAP, and many Lowrance units also support Navionics. If your lake is poorly mapped, each of the three brands lets you build your own contour map as you drive.
What a good fishing map gives you
- Detailed depth contours, ideally at 1-foot intervals on the lakes you fish most.
- Depth shading or highlighting that colors a chosen depth band, such as 8 to 14 feet, so you can see every spot in that range at a glance.
- Water-level adjustment for reservoirs and lakes whose level changes through the year, so the contours match the actual shoreline.
- Points, humps, channels, docks, ramps and hazards marked clearly.
- Extras on premium charts, such as shaded relief or aerial imagery.
Once you can see those features, the next step is knowing which ones hold fish; our guide to reading a lake for bass walks through points, breaks, humps and creek channels.
The main chart options
| Chart | Works with | Notable features |
|---|---|---|
| Garmin LakeVü g3 / LakeVü g3 Ultra | Garmin displays | Incorporates Navionics lake data; depth range shading; the Ultra version adds features such as dynamic lake levels and Auto Guidance routing, according to retailer listings. |
| Navionics | Garmin displays and many units from other brands; also a phone app | Widely used inland and coastal charts; Garmin-owned. Check the compatibility list for non-Garmin units. |
| C-MAP | Lowrance (and its sister brands Simrad and B&G) | Some Lowrance units come preloaded with C-MAP inland charts; retailer listings for HDS LIVE units cite 1-foot contours on about 4,000 lakes. |
| Humminbird LakeMaster and LakeMaster VX | Humminbird displays | Depth highlighting and Water Level Offset; VX Premium cards add shaded relief and aerial imagery, plus SmartStrike, which highlights likely fish areas on select lakes. |
Coverage counts and features change with each chart edition, and listings for the same product often quote different numbers, so check the chart maker’s coverage viewer for your specific lakes before buying. LakeVü cards, for instance, are listed as not compatible with Garmin units that come preloaded with Garmin Navionics mapping, so compatibility is worth confirming even within one brand.
Making your own contour maps
All three brands offer live mapping that records depth from your sonar and position from GPS and draws contours on screen as you drive:
- Garmin Quickdraw Contours creates maps on compatible Garmin units. You can choose to share them with the Garmin Quickdraw Community and download maps others have shared; according to Garmin’s manual, only the contour map is shared, not your waypoints.
- Humminbird AutoChart Live records depth contours to a memory card and, on compatible models, bottom hardness and vegetation too. Humminbird sells an AutoChart Zero Lines card as a base for building custom maps.
- C-MAP Genesis Live on Lowrance units builds maps with contours as fine as half a foot and saves them to a microSD card.
How to build a useful map
- Insert a memory card if your unit saves live-mapping data to one.
- Set the depth offset so the recorded depth is measured from the water’s surface rather than from the transducer face.
- Drive parallel passes at a steady speed. Space them closer on points, humps and ledges you care about, and run along contour lines rather than straight across them.
- Note the water level on mapping days, and use your unit’s water-level setting if the lake rises and falls.
- Fill gaps on later trips, and re-record areas after floods, drawdowns or dredging.
Pair live mapping with side imaging and you can save every brush pile and rock pile you pass on the same map; see down imaging vs side imaging.
How to choose
- Start with your display. Your brand largely decides which charts you can use. Our Garmin vs Humminbird vs Lowrance comparison covers how each ecosystem handles maps.
- Check coverage lake by lake. A chart with 1-foot contours on your home reservoir beats a chart with more lakes you never fish.
- Check how updates work. Some charts are one-time purchases; others include or require a subscription for updates.
- Decide about sharing. Community maps are a great shortcut, but anything you upload can be seen by others.
Maps are aids, not guarantees
Even the best charts contain errors, and reservoirs change as levels rise and fall and as silt and debris move. Watch your depth, keep a lookout for stumps, rocks and other boats, and slow down in unfamiliar water.
Bottom line
Use the chart that fits your fish finder and has detailed contours for the lakes you fish, and add live mapping for small, private-access or poorly charted waters. A good map turns sonar time into fishing time, because you arrive already knowing where the points, humps and channel swings are.
FAQ
Do I need to buy a map card if my fish finder has preloaded maps?
Not always. Preloaded charts may be enough if they cover your lakes in detail. Premium cards add detail, imagery or features such as depth highlighting on more lakes.
Can I use Navionics on a Humminbird or Lowrance?
Navionics charts are supported on many non-Garmin units, including many Lowrance models, but compatibility depends on the exact display. Check the chart’s compatibility list before buying.
How accurate are live-mapping contours?
They are only as good as your passes, depth offset and the water level on the day you mapped. Tight, steady passes and a correct offset make a big difference.
Can I make a map of a lake with no charts at all?
Yes. That is exactly what live mapping is for. Expect it to take several outings to cover a lake well.
