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Discussion Starter · #1 ·
Remember the days long before these high rez Navonics or C-Map Bottom Bathmetry (BT) plotter add ons? Wow, have we come a long way or what! While most anglers I know have just followed the releases of the latest add on, there are still a few guys out there building their own charts. We use to do it by hand. Making note of unusual features on our paper charts.

Times have changed. I have been doing my own charting for years. Most who know me know I have used Lowrance for over 20 years. A long while back Lowrance introduced the capability to record raw time series data. Most anglers saw no use, or just don't have time to make use of it.

In this post, I'll present some of the things we are doing with this very under rated (in my opinion) Lowrance capability. And, yes there are other units that record, I am just not up to speed on their capabilities. So, lets hear for anyone who is using this and how it benifits them.
 

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Discussion Starter · #2 ·
Here is a survey track we ran a while back. All of the sonar data was recorded for post processing on a PC. This includes Side Scan data. I will wrap up this topic with a demonstration of what we are doing with our side scan recordings.
The area under survey is near the 85a in the chesepeake bay.
 

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Discussion Starter · #5 ·
There are a few holes in the data, but databasing the recorded data allows you to overlap and combine until you have all that you want. Why go through the trouble..... Well, if you are interested in structure you should be interested in this. While the NAVIONICS, CMAP, INSIGHT, BLUE CHARTS etc all do a fair job and as far as knowing bottom depth and contours, they are fairly good. However, they do not provide detailed structure like this.
 

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Discussion Starter · #6 ·
Plotter Output

Having all of this on your PC is one thing. However, who brings their laptop on the boat? Not many and not for long! We have invested quite a bit in PC software so we have the ability to conduct very detailed area surveys. We can generate an output file for just about any plotter that will display additional contours ontop of your current plot overlay. Here is an overlay image;
 

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Discussion Starter · #7 ·
Notice that in the image above the colors changed. I remapped the colors to be relative to bottom hardness. The hotter the color the harder the bottom. If you are looking for hard vs soft bottoms this data is priceless.
 

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Discussion Starter · #10 ·
The HDS can continiously record the raw timeseries data. Within the data header there contains a bunch of information including GPS position and signal intensity. Changes in signal intensity are used to determine changes in bottom hardness. Right now we can only determine that a bottom went from hard to soft, or that the area has a hard bottom. However, studies have been done so that once we get this reference information into our software we'll be able to determine exactly what the bottom type is. All of this is currently done post processing on a PC, however overlays can be created to put back into your plotter so you can customize your favorate fishing holes.
 

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Discussion Starter · #19 ·
When we originally did this survey we had no capability to overlay the scan images onto the contour maps. So, our survey track was not optimized for a scan; it was optimized for determining bottom hardness and contours. Which means we made multiple passes over the same area. This will generate the best bottom hardness and contour image, but the scans loose detail. It is a software issue that is being worked on.
 

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Dr Depth works fairly well, I've been taking recording from an LCX-18 and loading them up, I've gotten some good detail on the BB rock piles using just the depth analysis, don't have the bottom hardness yet.
 
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