In case any of you fish in tidal areas or where water levels change, you need to be careful with Quickdraw. Scanning two areas near each other, when the water level changes between the scans, can create false bottom contours. It can make the bottom look very different from how it actually is.
This is an area in Puget Sound where I was drifting south close to shore and then back north on a path a little further out while the tide was at max flow. This created a scanned area with some over lap. As you can see, the Quickdraw map looks very different from the actual chart. There is no drop off where Quickdraw shows it.
The other issue in tidal areas is that the charts show depths at mean low tide, so if you are scanning at any other tide level, you will also get false drop offs, inaccurate depths, etc where the two charts but up to each other.
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