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Take out "preference" for S-101 over S-57 in S-98 Annex C. #47

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kusala9 opened this issue May 20, 2024 · 2 comments
Open

Take out "preference" for S-101 over S-57 in S-98 Annex C. #47

kusala9 opened this issue May 20, 2024 · 2 comments
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AnnexC Annex C Harmonised User Experience on ECDIS/INS

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@kusala9
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kusala9 commented May 20, 2024

TSM concluded after lengthy discussions that the current S-98 Annex C clauses requiring a "preference" for importing / loading (it doesn't specify which) S-101 over S-57 is technically unfeasible. This is currently documented in C-18.6

The primary reasons for this are:

  • Data Producer scheming of S-101 and S-57 may be completely different both in spatial extent and scale. This means there is no algorithmic way of determining what the optimal coverage should be when faced with S-101 and S-57 versions of the same dataset.
  • The end user may not necessarily want S-101 over S-57 and service providers may have service agreements which dictate what producers receive and when.

the only part of the existing clause to be left in should be "The question of handling simultaneous display of data in old and new formats is still to be addressed by the IHO at the time this document is being written". If such guidance can be written it may be re-inserted but the technical, commercial and end user challenges / impacts seem unlikely this will ever be more than a preference.

@rmalyankar rmalyankar added the AnnexC Annex C Harmonised User Experience on ECDIS/INS label May 23, 2024
@alvarosanuy
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Sections C-21 and C-21.1 (Ed 1.4.1) need to be populated with requirements on how to manage (load and display) S-57 & S101 data. We can't leave things completely up to OEMs if we want to have consistency. Producers and end users have to understand how things will work in practice. For producers, it will have a direct impact on the way they decide to re-scheme (or not) their S-101 cells and also the way they should plan their S-101 roll out plans.

Very simplistically one would think that ECDIS will fill the screen with S-101cells based on the already agreed Loading and rendering algorithms and that the rest of the display window will be filled by S-57 ENCs based on current loading practices.
For the areas where S-101 data exists, the 'overlapping' S-57' content is to be ignored for display and A&I.

Is up to producers to make sure they release their S-101 ENCs starting from their largest scale products.

When MSVS is < S-101 ENC minimumDisplayScale the S-101 product should be removed. If no smaller scale S-101 cell exists, then the area is to be filled using an S-57 cell (as per current loading practices based on Compilation Scale and MSVS).

I'm sure my logic has flaws but bottom line is ... we have to write down how S-57 and S-101 are to work together to fill up an ECDIS screen (whatever that looks like). Maybe 'Drawing Index' or MONG can now assist with this?

@kusala9
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kusala9 commented Sep 13, 2024

As we now have the loading/rendering algorithms in S-98 Annex C (or at least, we will do in the next version), there is an opportuinity to strengthen the advice given to implementers on DF provision.

Currently:

  • the annexes are reproduced in their entirety. They're included as a separate document for the F2F meeting.
  • the only guidance is using drawing index to ensure seamless portrayal between S-57 and S-101
  • when the move was made to take out preferential loading/portrayal it was stated that the service provider will have to manage the datasets on the customer ECDIS. This means ensuring the end user doesn't have any "overlapping" data - i.e. data in BOTH S-57 and S-101 which will overlap at equivalent CSCL/S-101 scale ranges. S-98 Annex C should probably offer this as background to how the portrayal is managed
  • Algorithm? I think at PT123 there was general consensus that MONG is a better way of doing it (and prepares the ECDIS for interoperability better) but it needs the edge cases dealing with (non-point features) to avoid any anomalies. This couild be slotted into the Phase 1 release but may have to be targetted for the Phase 2 release of S-98 Annex C...
  • you can't force producers to release largest scales first, this will be up to producers and service providers.... and we need to make sure the ECDIS has the right guidance to deal with each eventuality...
  • I think it's dangerous to make it any more complex, particularly telling them to fill with S-57 where they don't have S-101. As soon as you start down that road then the OEM has to equate S-57 with S-101 and the comparisons are extremely difficult to make, mainly because "scale" is different between the two products.

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