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Old 24-03-2019, 01:09   #16
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Re: No sounding depths/details on inland waterway charts

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Originally Posted by FreeSpearit View Post
SonarChart layer in Navionics is not especially crowdsourced, some of it is actually from Navionics employees that go out and do the depth soundings. Other data is from crowdsourcing. Navionics has an average of 2000 updates per day. You can see recent examples of updates in the bottom section of this page: https://www.navionics.com/usa/charts...latest-changes
Never heard of Navionic employees doing depth soundings. Soundings are done by the Hydrographic Organisations or Waterway Authorities and are made in the ENC format. That is the source for all nautical charts.

There are other sources, like Google Earth, Infra red images.

In the latest OpenCPN Version 5 MBTiles can be used.

Layers can be added with operation times and other info for locks and bridges.

Here an example of the ENC chart with the infra-red image of the same area.


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Old 24-03-2019, 01:13   #17
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Re: No sounding depths/details on inland waterway charts

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Navionics has an average of 2000 updates per day.
That's a funny quote we see since several years.

Most probably o-charts would be able to claim "more than 1000 updates/day" for oeSENC charts taking into account the updated charts coming from the different Hydrographic Offices and counting the objects involved. And if we then add the NOAA/NGA charts and the free InlandENCs, oh boy...
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Old 24-03-2019, 06:33   #18
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Re: No sounding depths/details on inland waterway charts

The Navionics sonar charts are largely crowd sourced in well trafficked areas. And their accuracy should be taken with a grain of salt. I find them useful in giving me a better sense of the bottom contour but often find the individual soundings to be inaccurate.

To the OP, I believe there is an option to toggle between sonar and non sonar on the iPad app. You may find that useful.

As mentioned relying on charts to provide accurate depth data outside of government channels in unfamiliar areas is unwise. Most of it has not been surveyed since before WW2. If I had a dollar for every time Iíve bumped bottom in 10í of charted water I could buy a new chart chip lol
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Old 20-04-2019, 21:13   #19
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Re: No sounding depths/details on inland waterway charts

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Originally Posted by meridian28 View Post
Minimum 9.9 feet on the rivers for barges. No depths shown on the charts

FWIW, the project depth, i.e., the depth that the COE seeks to maintain, is not always maintained. I have bumped bottom in a boat with a 6.5 foot draft inside a 9 ft. channel. I discussed it with a COE engineer, and he said he wasn't surprized.


Also, the project depth is different for different rivers.
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Old 25-04-2019, 17:53   #20
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Re: No sounding depths/details on inland waterway charts

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I think you will find that the detailed contours in programs like Navionics are not often updated. Most are 20 years old or more. I forget how to check but I think the date of the survey data is shown down in the bowels of some menu on Navionics app. Might be interesting to look at that.

The army Corp of engineers is responsible for making commercial navigation on inland waterways as safe as they can. They donít care about little coves that will never be used by commercial vessels. But the ACE charts are updated very often. So for passages on inland US waters the ACE charts are the most up to date you can get. And the least expensive.

Actually Navionics had 2000 updates per day to their charts. You can see the most recent updates here:
https://www.navionics.com/usa/charts...latest-changes
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Old 26-04-2019, 04:43   #21
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Re: No sounding depths/details on inland waterway charts

2000 updates per day over how much area?
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Old 26-04-2019, 04:57   #22
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Re: No sounding depths/details on inland waterway charts

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2000 updates per day over how much area?
The planet.
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Old 26-04-2019, 11:09   #23
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Re: No sounding depths/details on inland waterway charts

"I have bumped bottom in a boat with a 6.5 foot draft inside a 9 ft. channel. I discussed it with a COE engineer, and he said he wasn't surprized."
The world is not a static place. I've been literally 80' under the surface in what was clearly shown as a 40' deep channel. Channels subject to tidal action scour and fill, that's normal. Coastal barrier islands (Fire Island, Miami Beach, so many place in between) routinely move around and sometimes go away entirely.
If you have a static picture of San Francisco taken before the big quake...is it the same today? When parts of the Mississippi River close to shipping traffic because the water has gotten too low, does anyone run out to rechart it? Not really, they know it will change again before they can push out the numbers.
Both ACE and Navionics know the source of the data they are showing. Each can tell you how and whether more data is available from them, and if you're lucky enough to get a cartographer on the phone, they're often quite happy to tell you if there's another source for the data.
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