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Unknown Water Level -- No extensible codelists

José Enrique Frieyro de Lara
By José Enrique Frieyro de Lara Replies (4)

Hi everybody;


I'm joining this group hoping that you could assist me in clarifying some questions related to SR and OF data specifications and data models. I work at the Environmental Information Network of Andalusia (REDIAM) in Spain and I’m also involved in the national Thematic Group concerning topics 15 and 16 of Annex III, with the aim of developing a technical guide for SR and OF data transformation according to the INSPIRE specifications.

The first question that I’d like ask relates to the “no extensible” code lists, in particular, the code list “Water level value”. This code list is located in the application schema of Hydro-Physical waters and includes many differents water level definitions in an attempt to offer many possibilities to set up the water level reference (meanHighWater, lowestLowWater...and even definitions like “nearlyHighestHighWater”, etc.).

But wouldn't it be a good option to include a neutral value like “unknownWaterLevel”?

Would it be possible to suggest this extension in the code list in some way? I am aware the code list is defined as “no extensible” but the truth is that in most cases, when the coastline is not an administrative limit or a legal or political reference, the water level reference is not easy to define.

The data specifications suggest to choose the value “meanSeaLevel” when the water level is unknown, but I think this is not quite accurate.

In general terms, which would be the "official" way to propose this kinds of issues?

  • Katharina SCHLEIDT

    By Katharina SCHLEIDT

    Hi Jose,

    for my understanding, why would you require this extension? The 2 usages of WaterLevelValue are:

    • MarineExtent: here it's optional, so if you don't know it, don't provide it!
    • InterTidalArea: here it's mandatory, but I would expect there being some documentation available as to how this region was defined



  • José Enrique Frieyro de Lara

    By José Enrique Frieyro de Lara

    Hi Katharina;

    That’s truth, but I’m worried about the object “Shoreline” and the subtype “Coastline”. Also in this cases the water level attribute is voidable, but I don’t understand that Coastline definition have as a reference the water level, but actually, water level is an optional value in the Coastline object.

    So, in spite of the voidable stereotype, I think that water level will be an essential value, and It could be expected that in the future it will be mandatory. In this case, I would like to be able to include an “unknownWaterLevel” value better than other inaccurate value.




  • Keiran MILLARD

    By Keiran MILLARD

    Hi Enrique,

    The list of water levels is taken from an enumerated list (and associated definitions)  managed by the IHO.  This list does not have an 'unknown' water level and hence not present.  To allow for cases where no water level is present, the water level was made 'voidable' for Shoreline.  For Coastline the water level is defined by the definition of the feature itself in that it must be MHWS or MSL, depending on the tidal regime.



  • Begoña Vila Taboada

    By Begoña Vila Taboada

    Hi Keiran,

    I share Enrique's concern with this issue. What happens if, at the time of transforming old data, that information is not reflected anywhere? What value would we have to use in that case? MSL? voidable?


Marine & Atmosphere

Marine & Atmosphere

Oceanographic Geographical Features, Sea Regions, Atmospheric Conditions and Meteorological Geographical Features