Humminbird Side Imaging Forums
Side Imaging Forums => 798c SI => Topic started by: bobxxx on June 05, 2012, 08:44:48 PM
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what are spot soundings and how are they used
Bob
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must be too hard a question or to easy a question
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If I had to take a guess, they are submerged
structure (wrecks/cables).
Things that are under the water.
You can opt to display them (Visible) or not (Hidden) in your Chart menu.
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bobxxx
Spot Soundings allow you to display or hide spot soundings, which are depth measurements shown on the chart.
( optional-purchase Navionics charts only )
From owners manual. I didn't know either.
Mike
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thanks guys.It had me going.
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Spot Soundings are just what Mike stated from the operations manual. They have to be present on the map data before they can be displayed and will appear as numbers on the map data itself. Don’t confuse these with the depth contour line numbers.
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Greg
Thank you for expanding on what I copied from the manual. Your post makes it easier to visualize.
Any idea why those locations were chosen and what they represent?
It doesn't appear to have anything to do with depth.
Mike
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I do not know why these locations were chosen.
We were told (by the folks we made the maps) that these are actual water depth readings at those locations…
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Can we tell the actual lake level when the depth reradings were taken. It is all relative..
If we dont know this then the map depth can be off.
for our local area lake levewl can vary as much as 20 feet over thew summer..
So we are best to rely on the 2D sonar depth shown and not the map.
Chuck
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No we don’t know what the lake pool level was at when these were made.
I don’t know how old these are on the images I took too as that is from a pretty old map card (2006) and the depth contour data may be much older (and less accurate) than that. Anyone with a new Navionics Premium or Platinum map card see any Spot Soundings and can post some images from it?
I agree Chuck: using the 2D sonar is always the most accurate way to see what the water depth is.
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Yep, thank, just did not want to run aground thinking the map was accurate.
Better believe the sonar than the map..
chuck
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I know there is a depth offset for the transducer,,, is there any way to offset the depth contour numbers on a navionics map? Like if the numbers are at full pool(lets say 100 ft) and the normal level is 97.5 foot?? Like a 2.5 foot offset so the contour numbers are correct?
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the only setting I know of is the depth offset but that is keel to water line and only is +10 to -10.
Chuck
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I know there is a depth offset for the transducer,,, is there any way to offset the depth contour numbers on a navionics map? Like if the numbers are at full pool(lets say 100 ft) and the normal level is 97.5 foot?? Like a 2.5 foot offset so the contour numbers are correct?
No, not with the Navionics maps. We cannot interact with the data on them like that. The LakeMaster mapping cards have this and more capabilities but not the Navionics map cards.
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lakemaster cards looked way better,, but i dont live in a supported state..
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I understand. They are working on expanding their coverage areas but it will take time to do so.