Discover the World Below
Crowdsourced Charts You Can Make Yourself
Published: Sunday, May 30, 2021
By: Jordan Balbresky
Whether you’re a long-distance sailor looking for the next landfall, a racer that wants to catch every breath of wind to put you over the line first, or you are a driven angler whose biggest joy comes from that personal best catch, many boaters are pushed by a sense of discovery. In today’s electronic world with a few taps of a keyboard, you can download charts for almost any location, leaving almost no lands left to discover. But what if there were still uncharted waters? What if that drive to discovery leads you to want to peel back the blue of the lakes and rivers near you so you could see what’s below the surface?
When it comes to crowdsourced data, nothing on the water lends itself better to shared information than navigation data. You can get accurate, up-to-date charts created right from your depth sounder or you can download shared information from fellow boaters who cruised your favorite spots before. Products like C-MAP Genesis Social Map are made for those that want to discover for themselves. In fact, if it wasn't for the DIY capabilities of C-MAP Genesis, many lakes might never be accurately mapped at all. Some water bodies have already been completely mapped by community-minded anglers and cruisers, others are partially mapped, and some remain a blank slate, ready to be uncovered.
Think about the charts you use for your daily navigation. Though a minimum requirement for safe navigation, NOAA charts are general, not too detailed, and may be outdated. For example, the NOAA chart for Lake Michigan, the paper chart known as number 14901, was last updated in August of 2020 and provides general depths, navigation information, and potential hazards. This is great for basic cruising and sailing, it provides more than enough information for a prudent boater to enjoy their time on the water and come home safely. But as we all know, conditions can change frequently due to wind, waves, rain, and runoff. To keep NOAA charts up to date, the United States Coast Guard publishes Local Notices to Mariners which provide critical safety information about sunken vessels, shifting shoals, buoy changes, missing navigational aids, and other potential hazards. This means that you have to constantly update your paper charts for true safe navigation. It also means that these charts don’t have the level of detail you need if you are searching for the kinds of structure that fish congregate on for a successful fishing trip.
You can purchase electronic charts from manufacturers like Garmin, C-MAP, or Navionics that give greater detail, as well as additional features like bottom hardness, vegetation layers, and points of interest like wrecks or sunken structure. The price of these charts can range upwards of several hundred dollars. They often provide more detail than the NOAA charts, offering up to 1-foot contours, and some manufacturers, like Navionics, offer subscription packages that give you unlimited chart updates for a year, keeping them up-to-date.
In most cases, to get these 1-foot contours charting, companies run a computer program to estimate depths between government-drawn contours lines and fill in the blanks. Some companies use satellite data and advanced algorithms to come up with their contours. Some even have dedicated fleets of boaters that spend their time running up and down popular lakes to produce their more accurate charts.
But what if your home waters just haven’t gotten the attention deserved by those big companies?
With C-MAP Genesis Social Map, you can create 1-foot contours you can trust. The free, global, online collection of inland and coastal C-MAP Genesis charts are generated by the B&G, Lowrance, and Simrad Yachting communities of sailing, fishing, and cruising enthusiasts. Anyone with a free account can download Social Map charts to an SD card for use on the water in a compatible chartplotter. Users with an Edge account ($99 per year or $24.99 per month) can also see bottom hardness, vegetation layers, and have the ability to customize the color of their depth contours for easier readability. If you’re new to C-MAP Genesis, the first thing you might want to do is check if your favorite lake or river has already been surveyed and has a chart available for free download from Social Map.
Water bodies that are completely mapped feature charts with entirely blue-shaded depth areas; darker blue denotes deeper water and lighter blue indicates shallower water. On many water bodies that are partially mapped, you will see both blue-shaded depth areas and gray-shaded depth areas. The gray-scaled contours on Social Map charts appear in areas where the C-MAP Insight basemap has not yet been improved by custom contour mapping with C-MAP Genesis. When you and others in your area record and upload sonar logs of boat trips in those gray-scale areas, you can replace the less-detailed, gray-shaded contours with highly detailed, blue-shaded C-MAP Genesis contours, and eventually create an entirely new and amazingly accurate map.
For anglers especially, the benefits are revolutionary. Not only can you create custom fishing maps with 1-foot contours for lakes and rivers that have no other map in existence, but you can also improve contour detail on previously mapped waters and discover and dissect spot-on-the-spot areas overlooked by others.
If you are driven by the excitement of discovery, take a look at C-MAP Genesis Social Map. It’s easy to get started mapping your home waters and it’s free. For more information, visit www.genesismaps.com.
A version of this article appeared in the Launch Issue (May/June) 2021 of Great Lakes Scuttlebutt magazine.
tags: Navigation, Software & Apps
