[Public-List] Public-List Digest, Vol 4283, Issue 3

[Stephen Gwyn]

Hi Gord,
> 2201 is just the inland route strip chart? the one for our end of Georgian Bay is 2241 and was issued as a brand new chart reflecting the new survey not long ago.  2241 replaced the older chart.
So 2201 is based on a 1968 survey and only got replaced "not long ago"? 
So every 50 years?
My chart 3313 was discontinued recently, based on a 1992 survey, that's 
25 years.
It replaced 3310, surveyed in the early 70s, discontinued in the 90s, 
that's 20-25 years.
I wouldn't call a 25+ year cycle "regular re-surveying".

Hi R Kirk,
> So you're lower on the totem pole than Sable I, James Bay, North 
> Slope, etc. Wonder why they outshine you? More valuable, or just that 
> they haven't been done in a while. also wonder why they do that far 
> offshore area?
You'd have to read the full article:
https://www.mdpi.com/2220-9964/7/7/240/pdf
which discusses methodology but not specific
locations.

The following are educated guesses:

Sable Island, because it moves and because it's wrecked a lot of ships,

James Bay, Hudson Bay because it's poorly surveyed,
and becoming more important as the arctic stays
ice free longer; There is talk of making Churchill,
Manitoba a major port.

Not sure about North Slope.

Looking this up lead me down a Google hole to this site:
https://data.chs-shc.ca/map
which has all the available Canadian bathymetry available for download.
Not legal (or useful) for navigation, but cool none the less.
The CHS (unlike NOAA) does not make their charts available
online for free. This is as close as it gets.

SG