Questioning Navionics accuracy for small lakes

[muskiedreams]

I just got an email from Navionics that says they have expanded their 1 ft HD lake database. Just out of curiosity, I clicked on the link that gives the list of lakes by state to see if Waneta and Lamoka lakes were in the list and they were. I then went to the Web App and found Waneta Lake. I then clicked on the icon in the lower left corner which allowed me to select Sonar Chart. Here is the map I got. It shows 1 ft contour lines but I am familiar enough with the lake to know that much of it is incorrect. Especially the east shore. Check it out to see what I mean. Has anyone else experienced this inaccuracy with other lakes? Another question I have is, has anyone contributed to the community update function? If so, has your contributions helped to improve the accuracy of the maps?

[AnglingAddict]

My guess is this - I am sure they don't survey every square foot of the lake - I would bet that there is a lot of interpolation that goes on between contour lines vice real hard measurement which can lend itself to some inaccuracies.  In addition, differences between seasonal water levels, transducer mounting locations and angles and all other variable essentially render a true apples to apples comparison nearly meaningless.  No different than two people standing next to one another each with a wrist watch - which one is correct?   

[muskiedreams]

It is grossly wrong. At Swarthout point, there is a very steep drop to 30 ft within 30 ft of the docks. The Navionics chart shows it to be about 5 ft and that you have to go about 1/4 of the way across the lake to get to 19 ft.

[AnglingAddict]

I'm not surprised - I have noticed similar issues with the Navionics App for ice fishing.  I have a garmin on my boat and it doesn't seem much better.  I honestly think there is probably a lot of estimating and interpolation. 

[Gator]

Take a look at the South end of Keuka. They missed the entire Cold Brook delta, which is ringed by buoys and drops off quickly. I think that they take what they have and simply extrapolate by spacing one foot contours in between existing data sets. This is most notable near shore, where many of us who fish these lakes know the structure. Of course, there's always the disclaimer that these maps aren't meant for navigation...

 

Still, it's a far site better than nothing.

[goin hungry]

I have navionics+ and also update to the community function every trip. Basically, those maps will get you started, but then you need to record and upload your specific sonar logs. Then the next time you go out you will have all accurate information.

I was surprised myself to see that some areas that I know are heavily fished by serious guys doesn't have more information in their maps, but I think many guys don't take the time to record their loss and update their maps for the community. I can see why too - the instructions you get from navionics, and what's available on the web, really don't show all that you need to know and do to use the program and your sonar to it's fullest potential with the program and sonar that I have.

Here is a link to a post that I recently did on the more advanced info that you need to know to make use of it on Humminbird, but I'm sure some of it carries over to other models too:

http://www.lakeontariounited.com/fishing-hunting/index.php?/topic/57511-Navionics+-card-on-Humminbird-Units

I know it seems like a lot and can be frustrating that you paid a pretty penny for technology that isn't quite there yet, but after you do update your maps with your logs it's worth it, and I know that the technology will only get better - like the way you're already able to update your maps instantly if you have WiFi capability through certain phones and sonars.

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Edited April 27, 2016 by goin hungry

[muskiedreams]

going hungry, Thank you very much for the explanation. If I had seen your original post, (which by coincidence was only a few days ago) it would have shed some light on my curiosity. When I first read about this quite some time ago, it sounded really cool but I did not know how complicated it was to use the feature or how well it might work. I also wondered from time to time, why I did not see or hear anyone discussing it. Not even in fishing or boating magazines.I guess there is just not many people using it because it is not a very user friendly function. Maybe it will eventually catch on and/or become easier to use.

 

Do you know if updates are available on the web app for anyone who logs on? Can you see if your updates are there if you just log on as an anonymous user? So for people just looking before they hit the water or using a smartphone app would be able to see the added detail.

 

If more people start recording and uploading their data it could be very helpful on many waters. On the other hand, you still have to be careful about relying on it too much in areas such as the St. Lawrence. Although if you have carefully explored and mapped an area yourself you could have more confidence.

 

I did read somewhere a while back that you could use it to create your own more detailed sonar maps and be selfish and not share with the public (or only share with those you choose to share with). This could be a real game changer for local anglers in big tournaments. Some users might be concerned about others finding their fishing spots. I also wonder if there are options to share (or not share) detailed info such as catch (or species) info, snag locations, etc. I think you can add things like docks, landmarks, marinas and restaurants.

[goin hungry]

My understanding is that there is currently a WiFi enabled app that you can instantly link to navionics that will allow your maps to update

I do agree that it is a bit of a hassle and that not many guys seem to be uploading their sonar logs, but I recorded and update every time I go and hopefully everyone can benefit from that new detailed knowledge.

Might be worthy of a test try - maybe you screen shot the maps that come with the program, then scan and upload your Waneta or lamoka maps and see if they show the updates on other guy's maps.

It should update for everyone if it's truly a "community" update.

I only got the program a month ago and have been playing with it and figuring it out.

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[muskiedreams]

My understanding is that there is currently a WiFi enabled app that you can instantly link to navionics that will allow your maps to update

I do agree that it is a bit of a hassle and that not many guys seem to be uploading their sonar logs, but I recorded and update every time I go and hopefully everyone can benefit from that new detailed knowledge.

Might be worthy of a test try - maybe you screen shot the maps that come with the program, then scan and upload your Waneta or lamoka maps and see if they show the updates on other guy's maps.

It should update for everyone if it's truly a "community" update.

I only got the program a month ago and have been playing with it and figuring it out.

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I would have to find someone who fishes there and has a unit with the card and wants to try it out. I wish I had the money to sink into a new unit. The thing I wonder about also is how much it takes away from your fishing time. But eventually, you shouldn't have to update anymore in a small lake.

[goin hungry]

If you update then everyone else should be able to see it, like Swarthout point as mentioned above.

Once you get the hang of it it takes 5 seconds to start a sonar log recording, then you just stop and restart a new one every half hour or hour or so and it doesn't impact fishing at all, provided you have your ping rate set to high or auto, as I mentioned in my previous post.

Seeing to one ping per second as navionics recommends will render your sonar useless

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[justtracytrolling]

The new hummingbird helix 9 10 12 have what they call auto chart live....simply turn it on and watch the contours fill in as you cover ground....bout 800 bucks...Havent actually used it but come see me at the tiger tourney and I'll show you.

[bassandbucks]

On the small lakes the chips really don't show much at all. From what I can tell, if you go to the list of waters that Navionics has maps for you will notice they are the same ones that are on the DEC web page contour map. A great example is Casterline Pond (Cortland County). Casterline Pond is so small you could cast across so it's not like Navionics actually had someone map it. The DEC, maps were made years ago basically by someone driving around, or rowing in a boat with a depth finder. They show very basic information but no detail. I too was very disappointed with the Navionics chips on the small lakes I fish.

[goin hungry]

While it's true that sometimes you get basic maps, if you record and update your sonar logs you'll get the detailed contours on any body of water.

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[keukadude]

muskiedreams,

 

when I go to your link for the map of Waneta, I don't see 1 ft contours, and when I go to the Navionics list of lakes, Waneta doesn't have an HD after it.  Am I missing something? I have a Lowrance unit, and I'd love to have 1 ft contours, but Keuka doesn't have an HD after it either.  I called Garmin and they did survey Keuka and have the 1 ft contours, but I'd have to jump ship on Lowrance which has found me a lot of lake trout (not to mention the money)

 

I'm fascinated by goin hungry's post about doing your own logs (my Lowrance doesn't have this capability) and uploading them to Humminbird for the community, but it sounds complicated, and the first big step would be deciding what unit to buy.

 

goin hungry, if you had it to do over would you buy your 899 HD Di SI Hummingbird again? And have you been on Keuka?  Do you get the 1 ft contours?

[Chas0218]

If you do their live sonar charts when you are in that area it will allow navoinics to update their maps using the real-time data you gathered when running thru the area. I use this feature even tho I don't have the sonar charts on my gps.

[keukadude]

If you do their live sonar charts when you are in that area it will allow navoinics to update their maps using the real-time data you gathered when running thru the area. I use this feature even tho I don't have the sonar charts on my gps.

 

what FF do you have? You make your own sonar chart, which stays on your FF for you to use next time, and you send the data to Navionics?

[justtracytrolling]

Humminbird helix makes the map for you and it's easy. No uploading and downloading.

[Chas0218]

what FF do you have? You make your own sonar chart, which stays on your FF for you to use next time, and you send the data to Navionics?

I have a raymarine a68, it won't automatically update your charts until you log onto navionics and they update their maps and you download their update.

 

The humminbird system is the way to go and navionics is going to need to change their setup if they plan on people still buying their products.

[goin hungry]

Keuka - I do like my unit and the navionics program, but it all could be much more user friendly.

Yes, if you Save and upload your own sonar logs you will get the 1 ft contours for that area that will be visible in your ff unit after you upload the data to navionics and then reinstall your card in the ff the next trip.

This should then also then update to the "community" - meaning that others that update their cards should get the benefit of your uploads too, but I'm surprised that there isn't better info for the finger lakes given how many guys fish it, but maybe not enough techies are uploading their data...

If you have a sonar unit with wifi like the helix then your charts automatically update while you're driving I have been told. Looks pretty cool if you check it out on navionics website.

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Edited May 6, 2016 by goin hungry

[justtracytrolling]

The humminbird doesn't update from wifi....it creates the chart right on the head unit.

[goin hungry]

Right - using Sat signal I think? The other option involved instant update to your smartphone or mobile device from a ff that is wifi or Bluetooth enabled - as your sonar reads bottom it will transmit directly to your handheld and update the maps in real time. I've never used or seen either in action, just what I've seen on the web

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