Digital Contour Maps for Angling Success

Before a day of fishing, I would take one of my fishing chart plotters and plug it into a 12V lead acid battery at my desk. I would load the SD card into the slot and watch as the outline of the lake turn into a beautiful arrangement lines and colors. It looked like a work of art but it was my most valuable planning tool. I would then spend the next hour checking out the lake’s underwater features. Humps that the old cabin owner would have never knew about. The old riverbed winding through the reservoir like a snake. In fact, sometimes when I got bored, I looked at the underwater maps for fun.

As of February 9, 2021, Angler’s Edge Mapping has released a mobile version of their maps on the Avenza app. For those unaware, Angler’s Edge Mapping is a company that sells digital contour maps of many popular fishing destinations in Manitoba and Northwest Ontario. Previously the maps were only available on SD cards in a compatible Lowrance unit. With this game-changing news, the maps are now available for anyone with a smartphone or tablet. As a result of this news, I felt this would be a good time to discuss the benefits of digital maps and whether mobile or a sonar graph unit should be used to display the maps.

(Just to note, I have not personally purchased an AEM map on Avenza yet. I already own the SD card that can be read on my Lowrance units. However I have used similar mobile contour maps from a different app in the past. Avenza also has some preview AEM maps that allow you to get a feel for the app though it won’t give you detailed contours. While I reference AEM maps throughout this article, other companies have maps and business models that are similar. I am not endorsed by AEM; this article is simply a guide to digital contour maps.)

Benefits of Digital Maps

Being able to plan before the day of your trip is always good. Preplanning will always save time on the water, especially when time on the water is precious. With contour maps, I can typically plan my entire trip in the comfort of my own home. As most anglers know, trying to come up with a plan while on the lake having an unsuccessful day can sometimes be mentally taxing.

Digital maps help with navigation. Seeing those hidden prop-busting reefs ahead of time is a valuable asset. The cost of a map compared to a damaged prop or the motor’s lower end makes the decision easy to make. When ice fishing, drilling your hole into sand or rock will instantly end the trip and the blades. Again, the cost of maps won’t seem bad compared to a ruined day.

While fishing, my maps are pretty much always open. I like to be able to see incoming depth changes whether it’s drift jigging for walleye or dragging giant crankbaits for muskies. When I arrive to a new spot to fish, I will already know how I will be controlling the boat. The unit’s GPS will tell me precisely where I am in relation to the structure. Without mapping, trial and error may be needed to figure out how to properly fish the structure.

With most modern standard graph units, they come with the ability to create an underwater map while boating. Live mapping is time consuming as most likely you would rather be fishing than trying to create a quality depth map. For reference, Angler’s Edge Mapping travelled over 2,000 km to map the Red River from the south end of Winnipeg to the delta at Lake Winnipeg! As an angler, you should ask yourself whether you really want to burn that much time and gas to map a lake. With ice fishing, it’s nearly impossible to do live mapping. However live mapping is still a valuable tool to have on uncharted lakes during the open water season.

Now that the benefits of digital contour maps have been discussed, what is the best way to display them? On a mobile app or on a digital sonar unit?

Mobile Maps

Previously, maps were only available on SD cards in a graph unit. Often the map chips are only compatible certain brands or certain models. As a result, many people were in the dark regarding the secrets of the underwater. Mobile maps, like AEM’s maps on Avenza, have leveled the playing field. Now the requirements to access such maps are much lower, all you need is a few dollars and a mobile device. The Avenza app itself is free.

Depending on the business model of the map provider, you can purchase maps for individual bodies of water on the mobile apps. This is useful for those who only fish a small number of lakes. AEM even allows for sections of large bodies of water such as Lake Winnipeg to be individually purchased.

The convenience of having a mobile map is one of the main selling points. Instead of hooking up a graph to a heavy battery, mobile maps only require a few swipes of the screen. It is easy to send screenshots to friends. I also found it to be useful on fishing trips where equipment storage space is limited. When I’m hiking into the backcountry on foot, I find it difficult to carry my graph unit with me in the bush. By having my maps on the phone, it really takes away a lot of space and weight.

These apps typically come with navigational features utilizing your phone’s GPS. The ability to track trails, lay waypoints, measure distance and create routes is very useful. Not only will your fishing ability improve but it can be a valuable safety asset. Giant lakes like Lake Winnipeg can look the same in every direction. When ice fishing, it’s important to be able to track your route when navigating through the mazes of ice ridges, drifts and frazzle ice.

It should be noted that sometimes it can be difficult to utilize your mobile device while driving your boat, truck or snowmobile. Often both hands are needed to fully control the vehicle. If you are going to consider using your mobile device frequently for mapping, consider investing into a durable mount.

One issue I personally found having used mobile maps is they are dependent on the device’s battery. I spent an evening using my mobile map to troll bottom bouncers for walleye. The map was incredibly helpful, letting me stay in precise depths. However with the bright sun, the brightness of the device had to be turned up. Overall it was a pretty battery intensive app to have running all day. My phone ended up dying on the lake. I would recommend bringing a power bank for this reason. Your phone might be your only lifeline in the event of an emergency so conserving power is a must.

Something to consider is if the screen gets wet from water splashing or from rain. This can really mess up the touch screen functionality. I found this to be a significant drawback when fishing open water.

Personally I have found using my phone to be difficult for fishing as the screen is very small. This can potentially lead to eye and neck strain. My fishing style often has me looking at my maps constantly, especially for precise trolling. Though if you have a tablet, you can view the same map on a bigger screen. AEM allows for a purchased map to be downloaded up to 5 times for different devices so this is something you can take advantage of.

Digital Graph Units for Mapping

These days most boaters or ice fishers have a graph unit that is capable of accepting map chips. AEM for example, sells SD cards loaded with maps for a specific region or their entire catalogue. This is my preferred way of reading maps while fishing.

Usually my units are mounted on my boat or snowmobile already while being already connected to the starting battery. These screens are usually large enough that it’s easy to see the contour lines. I don’t have to worry about my phone battery draining, though I have to ensure not to kill the starting battery. Rain will not bother me as I can adjust the screen with the buttons on the side. Some higher end graphs are integrated with the trolling motor allowing the motor to drive along contour lines or to specific spots on the map.

That being said, not everyone owns the compatible graph units. The price of a GPS graph units is quite high depending on the model making the barrier of entry higher. As a result, the mobile maps may be the way to go for many people.

However if you are a serious angler, I highly suggest using graph units to read the maps. High end sonar is already an important requirement for high level fishing so why not read your maps on it?

Final Words

Digital contour maps are essentially cheating, no doubt. Whether you want to get them on mobile or on a digital graph is up to you and your fishing needs. Depending on your needs you might even want to have both.

Let us know in the comments if there are any other pros and cons that I might have missed.