Admiralty Leisure Folios - Subjective Editing

[RBJ]

This is my first post so I hope I am not covering old territory.

Ten days ago on a night passage into Plymouth via we noticed some discrepancies between the lights we were seeing and the characteristics shown on Leisure Folio Chart 5602.8.

Next morning we compared Admiralty Chart #030, Plymouth Sound & Approches with Leisure Folio Chart 5602.8 and noted the following discrepancies in the vicinity of Drake Island. Both charts were the latest version purchased recently.

The Bridge (4 Lit Beacons) - Omitted from Chart 5602.8
Six Large Unlit Mooring Buoys Nth of Drakes Island - Omitted from Chart 5602.8
The Bridge (4 Lit Beacons) - Not Shown on Chart 5602.8
Ash Buoy (Fl G 3s) - Shown as Fl G on Chart 5602.8
St Nicholas Buoy (Q R)- Omitted from Chart 5602.8
N Drakes Buoy (Fl R 4s)- Shown as Fl R on Chart 5602.8
NW Drakes Buoy (Fl(2) R 10s)- Shown as Fl (2) R on Chart 5602.8
W Vanguard Buoy (Fl G 3s)- Shown as Fl G on Chart 5602.8
Battery Buoy (Fl(2) R 2s)- Shown as Fl R on Chart 5602.8

To quote the Hydrograhic Office Web Site "Each folio chart is compiled using the same exacting standards and highly reliable data as that used to produce standard Admiralty paper charts and publications."

This being so it is difficult to accept that the numerous discrepancies noted above resulted from errors. I can appreciate that they may have some space problems given that #030 is 1:12500 and #5602.8 is 1:25,000 but this is not insurmountable.

However, one can only conclude that the "Leisure" product is being subjectively edited.

If so what are the criteria? Why are numerous hazards and aids to navigation being removed or altered on a "Leisure" product covering a busy area frequented by large numbers of leisure craft?

I have always assumed that a "Leisure" chart entitled "Plymouth and Approaches" would show the same aids and hazards as the standard chart but in a more convenient format.

If the leisure product is going to be materially different from the standard chart would it not be reasonable that potential purchasers be warned and the Leisure chart annotated accordingly.

What does the forum think?

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[Talbot]

makes a real nonsense of the snide remarks from Hydrographic organisations about accuracy of electronic charting. Personnally am happier using my C-Map chart than the Admiralty Small Chart Folios.

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[Shanty]

Checked the Hydrographic Office website:

current edition of Leisure Folio Chart 5602.8 is 1/1/2003
current edition of SNC 30 is 21/8/2003 - i.e. nearly 8 months more recent.

In theory, some of the differences could be due changes in the real world - hopefully reflected in NMs. However, looks like rather too many differences for this to be a full explanation. Have you tried contacting the HO? It would be interesting to hear their side of the story.


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[RBJ]

Our version of 5602.8 was Edition 5 dated 8/1/2004 which is based on SNC 30 dated 21/8/2003.

Chap I was sailing with has discussed with HO but apparently did not get a clear answer. He got the impression that there were difficulties scaling down.

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[Peppermint]

Re: Editing

The problems of chart production have changed over the years.

While old time cartographers scratched around looking for things to fill the blank sheet your modern guy is looking for stuff to leave out.

Scaling is the problem here and the UKHO will tell you that the salient features are in place. That what is shown is accurate but to prevent cluttering of the sheet they leave a lot of things out.

The Bridge being left out does strike me as being rather over editing.

I like the folio's if I'm in waters I know but for new areas I like more detail than they provide.

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[Twister_Ken]

One apple vs 4 apples

If chart A is at 1:12500 and chart B is at 1:25000, then chart A has 4 times more surface area to print info on, so I guess it's pretty inevitable in an area with lots of features, somethings are left off of chart B cf chart A.

But you do wonder who they consult before pressing the delete button.

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[Birdseye]

Re: One apple vs 4 apples

Interesting observations.

Chart scale has always governed the extent of detail shown. I dont have the charts you mention but I do have the Scillies in both full chart and leisure folio. At the same scale 1/25000, they show exactly the same detail as far as I can detect. All lights are shown the same way in both cases including timings.

Where the leisure folio covers part of the area at 1/12500 , it shows significant extra detail just as you have noted. Some local lights that are missed out on the 25000 and included on the 12500. This will obviously vary from location to location depending on how it is covered with lights - some places will have so few that everything can be shown on a 25000 chart.

Clearly there has to be some judgement used by the cartographer as to when the chart is becoming too cluttered, but personally I would think it sense to give light timings if you are showing lights since that is how you identify which one you are looking at.

The HO insist that there is no reduction in data, like for like, on the leisure charts - since it costs no more to print a cluttered chart than a largely empty one, I believe them. Am going to a meeting at UKHO in 2 weeks time - I will ask the people in charge for their comments and will get back to you






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[Peppermint]

Re:Even So.

Having spent time at UKHO and having seen the process at work it is, without doubt, a national treasure.

I know we all have a pop because they don't give much away for free and think they own the tides but we're fortunate that between the MCA, UKHO, RN and hundreds of organizations that feed info into them we get a great range of chart products at reasonable cost.

Like most parts of the establishment they do have to be a bit commercial now days but I think we're getting used to all that.

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[RBJ]

Re: One apple vs 4 apples

Thanks Birdseye. Would be very interested to hear what the HO say.

My post was not intended to criticise Admiralty Charts overall. I prefer them and started using them when they were still in black and white with fathoms and lovely drawings of key features.

I can understand the need to edit but these omissions and alterations puzzled me. IMHO in this particular case the leisure product is made inferior and in a very busy area for commercial and leisure craft.

The bridge is a useful shortcut particularly when approaching Plymouth from the west. It can only be used by relatively small craft yet it is ommitted from the leisure chart and shown on the normal chart. I cannot understand why light characteristics would be edited. Take them out altogether perhaps but don't change them.

Given that small craft are advised to keep to the edge of big ship channels it seems odd to omit buoys so located.



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