Reference to Compilation Scale

[Christian-Shom]

There is only one reference to Compilation scale in the S-101 PS (§4.5.3 : "The maximum display scale is considered to be the equivalent of the compilation scale of the data.") I am of the same opinion as Alvaro (post meeting November 2021) that this reference to Compilation Scale should be deleted from S-101 documentation for the benefit of scale range (and Max/Min Display Scales). CSCL is used for S-57 ENCs; Max/Min DS will be used for S-101 ENCs (including the loading strategy) and quoting the Compilation scale in S-101 PS brings no useful information. Moreover, the term "compilation scale" is misleading, as currently digital data is often compiled at a much larger scale than the one at which it is intended to be displayed.

[TomRichardson6]

Support the removal of this reference for improved clarity

[alvarosanuy]

I support the removal of this text.

[MikusRL]

Further is my personal opinion as a nautical cartographer, and thinking of what challenges I have come across when helping introducing the new standards into the HO offices and in their production systems.

Although I tend to agree with the above statements regarding the cleaniness and clarity of the standard definitions and terms in the PS document, but I am also of the opinion, that this is not the term as such which is used here from the existing S-57 standard, but describes the operation or work what compilers do when "finalizing" or "designing" the ENC as a navigational product, which then considers this maximum and minimum scales the product will be portrayed in ECDIS, specifically for safe navigation. I actually think from that perspective, that we should bring back into this PS this term even more, as this PS is ALL about that to be given to the mariner at the end of the day.

It is very easy to "lose" the description, which describes the complex operations and knowledge locked in the S-4, which distinguishes navigational ENC from just a set of all best available data joined in one file, and so far in the IHO domain, the word "compilation" has been used, which in one word, to my understanding, gives that distinction. Like Christian mentioned, this is the last place we have this word in this specification, and that actually could be worrying, not because it is still there, but because it is the ONLY place it is left. When the word "compilation" is used, then everyone then knows of what kind of "dataset" one is talking about. This calls also well together with AU proposed MaxDS definitions, where the description "Optimum ratio between the level of detail and the accuracy of the information provided." is used to try to describe, what means "compilation". And I do not think that even within the AU description, all "intentions" are included, what does the word "compilation" covers.

So perhaps it is a good sentence we have at the moment in the PS, but remove the "statics" of it in the words "...of the data.", and then this sentence gives a lot to educated in this domain people, and helps to educate also others or to remind, that ENCs base values are still the same and have not been cancelled with this new standard, but enhanced and improved ENC's wrapping, if it can be called like that. So would suggest to consider something along these lines: "The maximum display scale is considered to be equivalent to the scale used at the time the ENC is compiled according to IHO S-4 standard for the chosen navigation purpose ."

When you think of this from the bit more "helicopter view", with the new S-100 standard and S-101 PS so far we so much are concentrating (and been a bit pushed from "new modern GIS" community within HOs) on getting it right with the "new data" and "new GIS" parts, and want to follow the "modern" and "up to date" technologies, and might forget, that we need to bring with also what are the fundamentals we do it for and do it good on daily basis, because this is we who was this knowledge, but can forget to still put it in for those who are just coming on board or coming from the "modern GIS community" world, and just to remind it for ourselves too. It is THE ENC in the future we are describing in this PS here, correct? I understand that with S-100 in place we blur now much more this term of "compilation", and in some respect even try to put/design the compilation job on ECDIS by defining the S-98 - the Interoperability, I think we need to leave the word "compilation" in this PS where talking about the operation or in-hold of the S-101 dataset, and perhaps strongly consider to bring this term even into the S-98, not to lose the useful navigational "compilation", when all the S-1xx datasets are merged on the ECDIS display for the end user, or appropriate data been used in calculations by autonomous vessels, so the captain of the manually sailed vessel still could predict the actions of the autonomous vessels in his vicinity navigating on the same - meaningful to both decision makers data/ENCs.

My apologies for long entry, but I think this has not been a strongly considered or discussed so far while building the new S-1xx PSes and S-98, and I think that NCWG (sorry Mikko) has to step up bit more (not sure though in what form, perhaps a WGs official review of S-101 draft) now into the game here and make sure, that all applicable nautical cartography concepts within S-4, like "compilation", are considered where appropriate and integrated correctly from these stages up, into the developing S-101 and S-98 accordingly, or consider adjusting the S-4 accordingly out of the outcomes or developments of S-101 and S-98. And I think this one word "compilation" is one of those cases, where this cooperation between NCWG and S-101PS is needed to be seen that it has been considered when decision is made for S-101PS.

[Christian-Shom]

Thanks Mikus for this interesting input. My view is that with the end of Usage Bands and the introduction of Max and Min Display Scales, we are switching to a different model and that getting rid of compilation scale may be the best option. As "Compilation Scale" only appears once in the current PS, I would suggest removing it for edition 1.1.0. If it is later felt that it needs to be reintroduced, further work would be needed to propose ad hoc wording.

[MikkoHovi-FI]

I think @MikusRL does have a point.

All charts, even S-101, do have a scale (or scale range) they are compiled to. Otherwise things will get messy. This is regardless of how we call the scales in S-101. We should be careful not to go so far with avoiding certain terms, that the cartographers not already familiar with S-101 will have difficulties understanding what we are trying to say.

It is not necessary to use the specific term "compilation scale" towards the end user or even inside the product, but in the production process it still exists. Therefore, I think, it may still have its place in the PS when discussing the scales.

That said, I am not sure if the current text in 4.5.3 is completely true. As @Christian-Shom said, with the Max and Min Display Scales, the compilation scale should basically and ideally be seen as scale range - from Max Display Scale to Min Display Scale. This scale range is the scale the chart would optimally be compiled to. However, I believe, that many HOs will still pick one single scale to which they compile their data - the compilation scale.

[RichardCoyles]

I feel the reference to Compilation Scale should remain in the PS because HO's will be concerned with attributing MaxDS & MinDS to the Display Scale Range (DSR) during conversion (S-57 to S-101). I would be difficult to assign the DSR without first understanding the optimum display scale, and its equivalent in S-57 (The Compilation Scale) Also, because overscale is such an important function in ECDIS, it should indicated accurately, and therefor MaxDS should be the equivalent to the Compilation Scale in S-57.

[Christian-Shom]

Due to lack of consensus, the Sub-Group meeting 2022-10-19 agreed on keeping the wording as it is (retain reference to Compilation).

[JeffWootton]

After the editing session at S-101PT10 (November 2022) the single instance of the term "compilation scale" has been removed from Edition 1.1.0 of the S-101 Main document. There is only one instance of the term in S-100 (Part 16, clause 16-11.7). Further, the term "compilation scale" does not appear at all, nor is it defined, in S-4. The term does exist in the IHO Hydrographic Dictionary, however this is purely related to ECDIS and was formerly in S-32 Appendix 1 - Glossary of ECDIS Related Terms. Consideration may be given to retiring this term when S-57 is "sunsetted".

There are 5 instances of the term "compilation scale" in Edition 1.1.0 of the S-101 DCEG. For consistency, based on decisions at S-101PT10 and changes made in the Main document, these instances have been replaced with "maximum display scale of the data" for Edition 2.1.0. Close issue pending outcome of discussions at S-101PT11.