bigfishing85 Posted December 8, 2015 Posted December 8, 2015 Not sure if the image is showing up or not. Here is the link: https://www.topoquest.com/map.php?lat=34.30444&lon=-83.84886&datum=nad83&zoom=4&map=auto&coord=d&mode=zoomin&size=xl I am looking where it says Lakeshore Estates and then it looks to be like a big E where the high school is located. In here is where I fish at a local park and cove. I notice there are lines and it says 1060. What do the lines mean? I watched the video about how to read the map and I know those are contour lines but I cannot tell how deep they go. I am very sure there is a point there only because I have seen the lake drained so low you would walk out across in this area. Trying to get familiar with the maps and how to read them better. Any advice would be helpful until I can get some sonar on my boat. Thank you. Quote
Super User Fishing Rhino Posted December 8, 2015 Super User Posted December 8, 2015 I'm not sure, but I'll hazard a guess. Those lines are contour lines. The numbers are "elevations" which indicate the feet above sea level. Where the lines are close together the steeper the grade. You would be better off getting a map of Lake Lanier from a tackle store, or you can order them by phone. They would look like this, showing the depths and various features of the bottom such as standing timber, emergent vegetation and such. Like a topo map these also have gradient lines showing the depth in feet rather than elevations. The closer together the lines are, the steeper the banks. Where the lines are further apart, the more nearly flat is the bottom. You can order a map of Lake Lanier from here, and they are available in waterproof versions. http://www.atlanticmapping.com/ This is also interesting. You can download the maps to your smart phone, if it's an Android. It doesn't look like it's available for Lanier yet. http://www.atlanticmapping.com/androidcharts.html Quote
BKeith Posted December 8, 2015 Posted December 8, 2015 Usually, somewhere they tell you what the contour intervals are but I don't see it from what you have posted. Anyway, on that map, they are 20 feet. The 1000 line means that line is 1000 feet above sea level. That 1060 line means that line is 1060 feet above see level. Now, with a 20' interval map, you loose a whole lot of contour detail. It's very possible to have an point, hump etc that can be as much as 15' to 18' deep that just happens to fall right between two contour lines that would never show up on that map. That's why when you fish a lake like Lanier that has large changes in pool level. You get in your boat with a topo map, GPS (if you have one)camera, and note book, and you ride around make tons of notes. On key features, get out and actually walk to them so you can mark their exact location. I've got 50 years worth of maps notes and photos of the areas I fish on some lakes where I have scouted them while the water levels were way down. They are worth their weight in gold when the water is back to full pool. 1 Quote
Super User WIGuide Posted December 8, 2015 Super User Posted December 8, 2015 I'll second what these guys said, but you can get the info you need on the area you're fishing here https://webapp.navionics.com/#@6&key=cterGb%7BivO That site has all the current Navionics map information on it and will give you much better detail! Quote
Super User buzzed bait Posted December 8, 2015 Super User Posted December 8, 2015 WI beat me to it.... use the navionics maps online and you'll be amazed at what you might find FOR FREE Quote
Super User Wayne P. Posted December 8, 2015 Super User Posted December 8, 2015 I'm not sure, but I'll hazard a guess. Those lines are contour lines. The numbers are "elevations" which indicate the feet above sea level. Where the lines are close together the steeper the grade. You would be better off getting a map of Lake Lanier from a tackle store, or you can order them by phone. They would look like this, showing the depths and various features of the bottom such as standing timber, emergent vegetation and such. Like a topo map these also have gradient lines showing the depth in feet rather than elevations. The closer together the lines are, the steeper the banks. Where the lines are further apart, the more nearly flat is the bottom. You can order a map of Lake Lanier from here, and they are available in waterproof versions. http://www.atlanticmapping.com/ This is also interesting. You can download the maps to your smart phone, if it's an Android. It doesn't look like it's available for Lanier yet. http://www.atlanticmapping.com/androidcharts.html WI beat me to it.... use the navionics maps online and you'll be amazed at what you might find FOR FREE You can have the lake contour maps on your smartphone and/or your tablet. The Navionics Mobile App is for Android and iOS. Just get it from each's app store. I have it on 5 devices. Of course I also have the map cards in my sonar/GPS units too. This is the Navionics map of the creek arm of the terrestrial topo map. You can add a satellite image overlay on the Web App and Mobile App. Quote
Super User Wayne P. Posted December 8, 2015 Super User Posted December 8, 2015 One more thing that the Navionics Mobile App has is Water Level offset. If the lake is drawn down 10', just change the level -10' and the app will redraw the lake to the new pool level. Quote
BassMan85 Posted December 9, 2015 Posted December 9, 2015 Thank you guys very much! I have been fishing that area for striper alot and was wondering why they were in certain regions all the time. I think I see now why. I am not sure though what the blue areas stand for...are those very very deep areas? Thank you and I will try and get the app on my phone so I can keep it around when I am out there. Quote
BKeith Posted December 9, 2015 Posted December 9, 2015 A quick explanation. The blue are is the lake. Looking at that map, they have blue in the lake starting at a full pool level of 1071 feet above sea level. That's why you will see the blue between the 1060 and 1080 contour lines. Now you just start following the contour lines down and each one is another 20 feet deeper water. Each contour line goes all the way around the lake, about and below the water line. When you get to the deepest sections you will see they just make basically a circle. Now, since this is a 20' interval map, the actual deepest water could be as much as 19' deeper than the lowest line on the map. As already mentioned, the more separated the lines are, the more gradual the slow. The closer together they are, the steeper the slope. If there are several line very close together, that's a very steep drop like the side of a tall, steep, hill under water. The reason the stripers and hybrids are up in the channels like that, the water is cold enough they are coming out of the deep water into the creek channels going through their spawning rituals. Even though they don't spawn they still go through the act. Small swim baits to match the shad, popping corks with a three foot leader and a Betts Pop-n-Stripe, and 1/4" jigging spoons bounced off the bottoms are deadly on them now. If you want the huge ones, blue back hearing drifted at the depth they are marking on the sonar. If the sea gulls have got there yet, follow the gulls. If they are diving, there fish there. Quote
Super User Wayne P. Posted December 9, 2015 Super User Posted December 9, 2015 The blue areas are where there is no sonar data to create contour lines so it is given the shallow depth highlighting. Quote
BKeith Posted December 9, 2015 Posted December 9, 2015 OK, Wayne P. At first I was trying to figure out what you were talking about, but then I realized you are referring to the map you have posted and I was referring to the Lanier map he had in his link. Makes more since also, because I was wondering why he didn't even know what the blue area in the Lanier map he linked to was. Quote
FloridaFishinFool Posted December 9, 2015 Posted December 9, 2015 Some great map info already posted, but I'd like to throw some into this discussion... I have been map collecting for years here in Florida. I began collecting bathymetric maps long before the days of instant downloading and satellite imaging. I have maps for many of Florida's lakes going back into the 1960's. And over the years I have noticed significant differences between bathymetric maps made by humans who actually go to the lake and measure lake bottom depths and chart them as compared with satellite generated maps made by people and machines and technology who never stepped foot anywhere near the lake they make maps for. Today I have the advantage of being able to compare old school maps to satellite created maps and I have found that the old school maps are in my opinion more accurate and contain more details. For example, one lake I have fished on a regular basis, my old school map shows me a deep hole in the lake, but when I look at a satellite generated image it does not show the hole any where on it. So I guess my point is that old school bathymetric maps made by humans doing on-site mapping of the lakes is more accurate than the satellite generated images. My sources for the old school maps are free! I get them from various government agencies. You have to consider what government agencies have control over the waters you want to fish. And then turn to them for the maps. So I get a lot of my maps here in Florida from local county and city governments and find them in the storm water and run-off depts. usually. And here in Florida we have the state government mapping lakes through local state run universities like the "Lake Watch" program and the "Water Atlas" program. These government agencies do not use 100% satellite imaging for their bathymetric information! And I can only assume the reason why is because the accuracy is not up to the higher standard the government needs for proper water management. When you click the link that takes you to the University of Florida's "Lake Watch" program which includes mapping, right at the top of the page and the first image they show you is a man in a boat on the lake doing the mapping the old fashioned way- by hand, not by satellite. And there must be a reason for this as I have already mentioned above- it boils down to accuracy. These guys who measure by hand find things the satellites do not. And I want the benefit of this more detailed information showing me deep holes in my lakes those satellite images can not see. http://lakewatch.ifas.ufl.edu/MapList.htm I have never looked for maps in Georgia, but I would assume that many state and county and city governments work the same up there too and produce their own lake maps with tax dollars. All you gotta do is learn to find who has them and ask for them, and many are now online for free download like the "Lake Watch" program I linked to above. I just looked at the "Water Atlas" website, and they explain how they make their maps more accurate by combining hands on mapping with satellite imaging, but keep in mind that in the past many of the maps I have acquired were made long before the possibility of satellite overlays... http://www.lake.wateratlas.usf.edu/shared/learnmore.asp?toolsection=lm_bathymetric How are the data collected? (Methods) A Bathymetric Map is similar to a contour map. In making a bathymetric map a SONAR depth finder is used along with a Global Positioning System (DGPS). Researchers map a course around the perimeter of a lake and then navigate parallel transects using the depth finder to store various depths of the lake in a consistent pattern. This data is then used to create a map showing the contour of the bottom of the lake. Florida LAKEWATCH, at the University of Florida's Department of Fisheries and Aquatic Sciences, may also provide data. Calculations GIS (ArcView/ArcInfo) processing using Triangulated Irregular Network commands. Caveats and Limitations Many lakes have not been professionally surveyed in order to accurately determine their elevations. This limits the number of lakes that can be meaningfully mapped in the near future. Bathymetric maps herein are for educational purposes only and are not to be used for navigation or professional survey reference. ------------------------------------- ADDED: Another reason I go to my local and state governments for lake maps is because satellite generated images can not and will not tell you where the state or local governments have sunk plastic trees for fishing improvements in certain areas. Right now here in Florida the state is sinking a number of these plastic trees into lake Griffin near Leesburg. There is not one map company on the planet who can give you this information and it will never show up on their satellite generated maps. So I stay in contact with and up to date with my state Fish and Wildlife Commission and regularly receive updates on their operations around the state which I take full advantage of when I can. Sometimes they provide me with their maps and sometimes I have to add it to maps I already have myself. Either way, it is great information to have and stay up to date with. Quote
Super User Wayne P. Posted December 9, 2015 Super User Posted December 9, 2015 To show the benefit of the Mobile App settings, I changed the lake level to -10' and the software redrew the contour lines to that lake level. Then a lot of the docks are not in the water or barely in the water: Quote
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