[Public-List] Charts and depth sounding

[Gordon Laco]

That’s unfortunate… the Great Lakes, the Arctic and the Atlantic Coasts are still getting a lot of attention.

In the past ten years nearly all the charts have been reissued, with of course the Notices to Mariners being published with incremental updates monthly. 

When I served on the Pacific coast in the Navy 2006-16 the updates seemed as brisk and comprehensive…


Gordon Laco
www.gordonlaco.com





> On Feb 18, 2022, at 9:16 PM, Stephen Gwyn via Public-List <public-list at lists.alberg30.org> wrote:
> 
> Hi Jim and Gord,
> 
> While the Canadian Hydrographic Service does resurvey
> continually, they, just like the Americans and the British have
> relatively limited budgets and don't survey everywhere on regular
> basis. Some parts of the bottom, particularly those with lots of
> commercial operations get survey quite often. Other parts,
> relevant only to pleasure craft, get survey rather
> infrequently. Some charts of the west coast that I have are based
> on surveys from the 1950s to 1970s. Maybe the rocks haven't
> moved, but the sand has, and some of the rocks were
> missed the first time round. When I was in Haida Gwaii in 1990,
> some parts were still only sketched out. Some bays had one line of
> soundings going in, and one line of soundings going out, and a
> shoreline. Haida Gwaii was resurveyed (or more accurately
> properly surveyed for the first time) in the mid-to-late 1990s,
> but I don't think anything has happened since.
> 
> For a lot of coastlines the best, most up-to-date surveys are
> actually done by private outfits using crowd-sourcing, by
> collecting data from regular users who have keep their GPS and
> sounder running continuously.
> 
> On a related note, in some places, the current tables provided by
> Navionics are better than those from the Canadian Hydrographic
> Survey. For Johnstone Strait in particular, the CHS predictions
> are completely useless. No idea how that's possible. I asked
> Navionics, but they just responded that is proprietary
> information.
> 
> SG
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