Imray to stop publishing paper charts

[requiem]

I think I need to be clear - I wasn't clear. I wasn't talking about whether there are updates or not. That is very simple. What is important is the quality of the updates: are they correct? Are they up-to-date?

Oh... I intentionally left that off, thinking it was too much into the weeds.

If you're getting charts from the HOs or an appropriate clearing house, what you're getting is the "official chart" with all the properly-vetted updates. If you're using an app that's supplying its own charts, all bets are off.

E.g. you purchase a popular app with its chart package for the Florin and Guilder coastlines, perhaps they've integrated newer data from a survey they commissioned of the popular Guilder coastline, but since Florin is rarely visited maybe the app company only purchases updated charts every year or two.

Best way to check might be to take a sampling of chart corrections and see how quickly they make it into the private chart product.

 

[dunedin]

….

Some chart providers issue updates fortnightly, others quarterly, etc, but at least for the subscription period the updates should be free.

Bear in mind the little known fact that the official hydrographic data may not be issued to chart publishers more often than every 2-3 months. And sometimes the HO can take 6 months or so to update their chart databases with changes.
So your “daily updates” May in fact have official data that is still many months out of date compared to the real world.

 

[Egret]

Compliments to Tillergirl for issuing indicative information on some changes to depths in the Thames Estuary, ahead of the more formal changes which may come on charts over time, and also for clarifying current information in another thread where a channel is becoming shallower but published information in various sources varies. Maybe people with local knowledge in other areas could do similar. Of course it may be that with all electronic charts, the updates may come quicker and more frequent, but changes are dependant on the collection and verification of data, and whether/how information collected by users can be incorporated. Hopefully the 'Crossing the Thames Estuary' publication will continue.

 

[AntarcticPilot]

Compliments to Tillergirl for issuing indicative information on some changes to depths in the Thames Estuary, ahead of the more formal changes which may come on charts over time, and also for clarifying current information in another thread where a channel is becoming shallower but published information in various sources varies. Maybe people with local knowledge in other areas could do similar. Of course it may be that with all electronic charts, the updates may come quicker and more frequent, but changes are dependant on the collection and verification of data, and whether/how information collected by users can be incorporated. Hopefully the 'Crossing the Thames Estuary' publication will continue.

Collection and validation of data are not trivial tasks, and QA often involves as much effort as data collection. Even in frequently surveyed areas, an update frequency less than months - quarterly at best - is probably unattainable.

 

[tillergirl]

Amen to that, AP. And trying to apply several QA processes to Echart updates isn't exactly easy (or fun). I shall continue to monitor until it is time to go afloat next season (when of course, all my in-sub Echarts will go on-board!).

 

[steveeasy]

For those interested in preserving this legacy, we are offering a unique opportunity to acquire the chart business and/or rights to the Imray name, enabling a continuation of our tradition within the global maritime community.

Surely there is some one out there who will take this on. I’ve bought quite a few charts over the years. If I ever, which is highly unlikely to be in the middle of the Atlantic, I’d want a paper chart. Luckily I’ve bought them. They remain unused.

Steveeasy

 

[lustyd]

Do they really do that? Do you actually check?

Yes and yes. I have Starlink and have connected all the devices with Ethernet though. Obviously if you don’t have everything set up properly then they won’t update.

 

[penberth3]

For those interested in preserving this legacy, we are offering a unique opportunity to acquire the chart business and/or rights to the Imray name, enabling a continuation of our tradition within the global maritime community.

Surely there is some one out there who will take this on.....

Well, no! Read the posts above explaining what's involved in updating, publishing, distributing etc., in a declining market.

 

[Egret]

Out of interest how are chart depths updated nowadays by HO and realistically how often. Do they use satellite? I have a old chart which says parts are based on a survey of 1888, with the new chart not being much different, so maybe charts are just an indication - proceed with caution. On the most recent chart I bought, I found that a buoy had been moved since it was printed so maybe it is difficult to keep printed charts up to date, Big advantage of the electronic chart is the spot showing where you are, but it only lasts as long as the batteries so you need a position on paper as well.

 

[AntarcticPilot]

Out of interest how are chart depths updated nowadays by HO and realistically how often. Do they use satellite? I have a old chart which says parts are based on a survey of 1888, with the new chart not being much different, so maybe charts are just an indication - proceed with caution. On the most recent chart I bought, I found that a buoy had been moved since it was printed so maybe it is difficult to keep printed charts up to date, Big advantage of the electronic chart is the spot showing where you are.

Satellites can't do depth at the resolution and depths required for charting; it has to be a ship or boat survey. Swath bathymetry is widely used, but that requires many ancillary measurements of temperature and salinity for accuracy.

The bottom line is that hydrographic survey is resource intensive, both equipment and personnel. And the post acquisition processing is also highly skilled and labour intensive. Unless there is an economic justification, as in port areas or developments such as wind farms, if the existing survey is "good enough" it won't be updated. In many places, 19th century charts are adequate, as the area is rocky and unlikely to change. The basic survey is as accurate as a modern one, and will have been adjusted to modern mapping datums.

To give an indication, detailed terrestrial mapping of a few square miles of Antarctica usually took several man- months of work, not including field work.

PS. Satellites can do depth, but only off the continental shelf, and with fairly low absolute accuracy. The technique is inversion of highly precise measures of sea surface elevation.

 

[Egret]

Thank you. Much appreciated to get an understanding where finding depths not as indicated on charts. We tend to think that anything on a computer is instantly updated, but don't appreciate the work which would be involved in the background.

 

[requiem]

In many places, 19th century charts are adequate, as the area is rocky and unlikely to change. The basic survey is as accurate as a modern one, and will have been adjusted to modern mapping datums.

I'm struggling to put my finger on the link, but some time ago I ran across a NOAA article on this topic which had a nice overlay of some 18th century survey data on a modern chart...

Egret: it's important to keep in mind that every measurement has some level of error associated with it. The old 18th and 19th century surveys, whilst still generally accurate in terms of depths in rocky areas, can suffer from a lack of resolution and horizontal position error. It's quite possible for them to have missed rock spires that modern multi-beam sonar would have detected.

People have come to expect precise positions thanks to GNSS systems, but that doesn't mean everything on the chart was placed with such accuracy. Coastlines might be more accurate, but the placement of a sounding or remote atoll would be dependent on how precisely the ship could fix its own position. Here's a crude illustration (source):

 

[dunedin]

Out of interest how are chart depths updated nowadays by HO and realistically how often. Do they use satellite? I have a old chart which says parts are based on a survey of 1888, with the new chart not being much different, so maybe charts are just an indication - proceed with caution. On the most recent chart I bought, I found that a buoy had been moved since it was printed so maybe it is difficult to keep printed charts up to date, Big advantage of the electronic chart is the spot showing where you are, but it only lasts as long as the batteries so you need a position on paper as well.

It is always worth looking at the Survey Sources, shown as a note at the side of a paper chart somewhere - as I think you are referring to. (Although one big issue with electronic leisure charts is it is virtually impossible to find these.)

The reality is that there are virtually no “official” surveys nowadays except for waters

(a) used by commercial shipping; or
(b) where some other commercial activity is planned or taking place - harbour development, wind farm, mineral extraction etc.
Hence the gap that needs to be filled by private surveys - which don’t make it onto official charts.

 

[AntarcticPilot]

I'm struggling to put my finger on the link, but some time ago I ran across a NOAA article on this topic which had a nice overlay of some 18th century survey data on a modern chart...

Egret: it's important to keep in mind that every measurement has some level of error associated with it. The old 18th and 19th century surveys, whilst still generally accurate in terms of depths in rocky areas, can suffer from a lack of resolution and horizontal position error. It's quite possible for them to have missed rock spires that modern multi-beam sonar would have detected.

People have come to expect precise positions thanks to GNSS systems, but that doesn't mean everything on the chart was placed with such accuracy. Coastlines might be more accurate, but the placement of a sounding or remote atoll would be dependent on how precisely the ship could fix its own position. Here's a crude illustration (source):
View attachment 186506

In most coastal areas, the ship or boats position would be determined trigonometrically using multiple cross bearings and horizontal angles using a sextant. Also soundings would be taken along lines, either on compass bearings from fixed points or using temporary leading marks. Only offshore would position fixing would rely on astronomical fixes. So the precision with respect to fixed landmarks would have been comparable to uncorrected GPS locations.

Areas with possible pinnacles would often be swept using a weighted rope suspended between two boats. You will sometimes see that annotation on old surveys.

 

[tillergirl]

Seabed mapping services Clcik on the VORF.

 

[st599]

It is always worth looking at the Survey Sources, shown as a note at the side of a paper chart somewhere - as I think you are referring to. (Although one big issue with electronic leisure charts is it is virtually impossible to find these.)

The reality is that there are virtually no “official” surveys nowadays except for waters

(a) used by commercial shipping; or
(b) where some other commercial activity is planned or taking place - harbour development, wind farm, mineral extraction etc.
Hence the gap that needs to be filled by private surveys - which don’t make it onto official charts.

This is one of the issues raised in the RIN report. The charts required for a navigation device for coded vessels needs to show the dates of the survey and suggest an accuracy. They also currently need to use HO data only, but most of the stuff yachts care about, marinas, slipways etc. are added by the non-HO agencies.

 

[Egret]

All much appreciated, especially the Admiralty link from Tillergirl, and hopefully it will be helpful to others . Seeing the amount of work being done on soundings, it is worthwhile buying the charts while they are still available. My background to the question is I have had effectively a 30 year gap but am finding less water in places where there used to be plenty, but was finding variable information on published sources and was uncertain how up to date the information was.

 

[requiem]

Areas with possible pinnacles would often be swept using a weighted rope suspended between two boats. You will sometimes see that annotation on old surveys.

Do you know when that was introduced? Over here, I find references to it coming into play just after 1900.

Along the west coast of Mexico, for example, many of the charts are based on surveys done by the USS Ranger in the late 1800s, and I'm told that apart from major ports it hasn't been re-surveyed much in the meantime. I suspect at least the coastline has been tidied (previously reports had it off by up to a mile in some places), and remote pinnacles are still a risk.

The other image I had in mind was from Cook's exploration of Alaska, so I expect also prior to wire-drag. And yes, his soundings otherwise matched up well with the more recent data!

 

[tillergirl]

hopefully it will be helpful to others .

I fear not. The UKHO did ask me to consider using it and so I researched the possibilities The cost, I'm afraid, is prohibitive. So start with standard GPS sensors are utterly hopeless as to altitude so we would need to start with a new sensor which is a lot of money - even when I was kindly offered a new one at cost. And then there is some new software and a third party service. A bridge too far for the amateur. The cost can only be justified by income. The trouble is, as progress has progressed(!), the costs have risen and risen. And it isn't just about the cost of the kit. The time involved is significant and the post processing also takes time just getting the data ready to submission to the professionals. It is no wonder that professional surveys are only commissioned for commercial reasons.

But a lot of good can be done by an amateur albeit an amateur suffering from 'anorakism' ("a person who has a very strong interest, perhaps obsessive, in niche subjects. This interest may be unacknowledged or not understood by the general public. The term is sometimes used synonymously with "geek" or "nerd" ). We ought acknowledge a lot of good work by the professionals on our behalf such as the PLA. If they can, they do include check surveys over the sands which helps us. Also when I told them about the new old wreck in the SW Sunk swatchway, the PLA took the trouble specially to go out of their way to identify the safe water over the wreck. No ship would be interested in that place.

I am pretty certain Imray would continue producing paper charts IF people bought them.

 

[phlip]

Thank you all!

It's been a few (8?) years, but people may remember the buoyage of the lower Thames got moved around a lot over maybe a couple of years, as dredging progressed (presumably to support bigger ships getting to Thames Gateway and Tilbury.) At the time we were being very careful with our chart updates, purple pen 'n all, recording every ship's anchor chain abandoned in 50m of water in the eastern north sea etc. and similarly irrelevant details. We became aware that while Imray were pretty quick with including the Thames channel alignment changes in their update lists, the same could not be said for Navionics: at one point they were more than a year behind. Just because they've got an update pipeline that can produce daily updates doesn't mean they're ingesting the notices to mariners as carefully as they could/should. I wonder whether the consolidation implied by their acquisition by Garmin is leading to improvements. I should mention that I've not seen such significant lapses by Navionics since we moved down to the south coast in 2021. As we're moving back to muddier territory next spring, I imagine we'll be paying more attention to paper updates, partly as a cross check to the electronic ones.