How to read Navionics/Topographic maps effectively

Hey Folks!

So I'm currently on my second season of ice fishing, and have not had much luck so far except for maybe 2 Jumbo perch and a lot of dinks. I've been out to Bay of Quinte two times, but haven't hookd into anything. I'm just wondering if anyone could share their insight on how to read Navionics/Topographic maps to effectively locate structure and potential fishing spots. I'm not asking for anyone to give out any secret spots, just their knowledge as I'd love to learn how to locate structure and narrow down good places to start fishing and increase my chances of hooking up with fish. As of now I feel like I'm just guessing and not using Navionics to my advantage as I don't really know what I'm looking at except for water depth. Any help or expertise would be greatly appreciated! Here are some examples of spots I've marked and tried, but these spots were chosen without really knowing what to look for. I've looked for tutorials on YouTube, but haven't found anything very helpful so I thought I'd see if anyone here can share.

These two are of Bay of Quinte targeting Walleye:


These two are from Cooks Bay out of Gilford and Willow Beach targeting Perch:


This one is of Kempenfelt Bay. I haven't tried going out to target Lake Trout or Whitefish yet, but would love to get out and give it a go this season. Not sure where to start looking except for deep water(which I've marked):


Looking forward to any insight that can be given, thanks so much!

This post has been edited by adrian0524 on Jan 17, 2017 - 08:54 pm

It looks like you do know how to read them? The lines represent depth changes. It seems like you're asking people to point to a specific spot on those maps for you to fish, which no one will do. Watch any video with Bob Izumi, he always talks about points humps and saddles. Google those terms, it should help.

Thanks for the input. I actually don't know if I do know how to read them, but it's good to know I'm on the right track. I've really only been marking the holes with deeper water, but not much luck. Definitely not asking anyone to point to a specific spot as I'd much rather mark a spot myself and find them on my own, much more rewarding. I'll definitely look up some videos of Bob Izumi.

"X marks the spot "

With topographic maps, if you can, try and imagine them in a 3D landscape. For me I try and be careful not to get enticed by "nice looking" shapes. For instance, the second Cooks Day image, it looks like a nice shape/structure, but when you think about it, its supposedly a 1 foot depth change over quite a large distance, so it really is essentially flat there, PLUS these maps aren't always super accurate.

So, the closer that the lines are an a map, the faster the change in depth, the further apart the slower (flatter) that area is.

Different species look for different types of structure in the winter, so base what you look for on what your target species is using. In general, I try and always put myself in an area where I can try a variety of different depth, that way, if you can't find fish at a certain depth, you don't have to walk a km to try something new.

Hope some of that helps.

Unfortunately it's a little trial and error and time spent on the water. There are a lot of conditions that affect fish behavior and movement. Schooling fish may be there one day but not the next or following bait etc.

There are lots of useful youtube videos about catching jumbo perch and slab crappie. (Clam fishing team has some good ones) Sometimes the bite is off and you may be on fish but they're not hitting. Or, not there. If you have electronics it'll be easy to see what's going on below.

The good thing about fishing is that there's always something to learn. I think you have the right approach. Don't give up. You'll begin to be more successful as you go.

Look for sharper transition areas when you're looking for new water. The closer the lines, the sharper the drop. Like NorthWaterAdventures said above, the contour shapes you picked out might look good, but in actuality, you're fishing a flat bottom area with how far apart those transition lines are. Now if you were to take those same contours and mash all those lines together where you have a transition area of 10 ft over a short distance, I would be setting up shop there.

When I'm targeting walleye I'll target transition areas up to 25 ft, not usually any deeper. There can be deeper water around and they will come up to feed in the evening. But 15-25 FOW transition areas are what I'm looking for.

Just remember when you're reading these maps, the closer the lines, the sharper the drop. Pop a bunch of holes in a line to try and get rig ontop of these transition areas.

Best of luck, tight lines!

Glfpro

Good Advice,

Reading, looking for spots on a Topo map is a common topic for the pros too.

Do some reading there as well, good ol Gord Pyzer will set you right.

the way you can read them is by looking around a specific spot and follow lines. each line is a contour and they will have a depth somewhere on it. following lines and indicating what depth values are on each line will give you a general direction on which way the bottom is moving. the closer the lines and larger the jumps between depth values show how steep or steady a drop off is. usually pretty simple to use. just know how up to date the maps are is useful as the maps arent 100% accurate but a great starting tool

Latest episode of in depth outdoors covered this very topic in a beginner friendly manner:
https://www.youtube.com/watch?v=eWvgzVrqJeE

You are on the right track, keep in mind seasonal daily movements. Based on the specie of fish you're after is going to help narrow you in even more.

Spots on a map are going to help you get into a general area, using your sonar to find the right bottom is another tool to help you find the "spot on the spot".

Weeds, sand, rock, gravel, clay, and transitioning bottoms.

Thanks for all the input guys, all some great and useful information here. I can definitely see now some of the spots I chose were pretty flat, and trying to picture it as a 3D model is really helpful.

From this I can assume that I should stay away from flats as they wouldn't hold fish and look for areas with close contour lines indicating a quick change in water depth? Also, for these spots, where would be the best place to setup in terms of a quick change in depth. For example, if I find a spot that transitions from 10ft-25ft very quickly, should i setup at the 10 foot mark, in the middle, or where it hits 25 feet? (shallow, middle, deep) Or maybe I would punch holes and try all 3 depths?

Once again, thanks everyone for their input! It's great to hear from people who are more experienced and know what they're talking about. This will definitely help me in pre-planning my fishing trips by marking potential spots I should try before heading out.

Thanks for posting this video! Great explanation from the In Depth Outdoors team, I watch a lot of their videos and this was really helpful for a beginner to ice fishing like me.

Navionics will show weed lines if they've been marked. But I can't find a way to search for them or anything like that and can only see them when zoomed in really close.

Just last weekend I was looking at a mark from previous seasons and only when zoomed in as close as I could get did I see a mark for a weed line right nearby... just need some cold temps to be able to safely get to the mark

Came across this thought it was related to this thread.

Fishing structure and cover for largemouth bass
http://www.bass-fishing-source.com/largemo...-and-cover.html