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Associating LandCoverUnit instances to their parent LandCoverDataset instances for WFS filtering?

Hi all. I have a question regarding the (either non existing or me not being able to detect it) a mechanism in the LandCoverVector.xsd to associate LandCoverUnit instances to their parent LandCoverDataset instances (whereas the vice versa one exists i.e. the "member" attribute). As I am implementing a WFS (using Geoserver) to serve the CORINE data (for multiple year datasets), this seems as a quite a limiting fact to me. For instance if my WFS serves LandCoverUnits for several LandCoverDatasets, how would one, in such a situation, create a filter requesting a set of  LandCoverUnit instances of a particular dataset for a specific area? As this is the first INSPIRE compliant WFS 2.0 I am implementing, it's not impossible that I've missed something on the way, and if so I apologize in advance.

  • Stefania MORRONE

    By Stefania MORRONE

    Hi,

    please find below an extract of the "Technical Guidance for the implementation of INSPIRE Download Services", stating that a separate WFS endpoint should be provided for each different dataset.

    I am not a WFS expert, but, as far as I can understand, in your case you could provide one different WFS endpoint for each year.

    Just to make an example, should you create a WFS for the dataset related to year 2006 , you could then submit something like the following to get the relevant land cover units:

    http://.../LCDataset2006?service=WFS&request=GetFeature&version=2.0.0&typename=lcv: LandCoverUnit

    Hope this helps

    Stefania

  • Hrvoje Matijević

    By Hrvoje Matijević

    Hi Stefania,

    I must admit that I've somehow missed that specific requirement. This makes it clear, and eliminates the aforementioned WFS filtering problem. If you can only query a single dataset then there is no need to filter the response according to the dataset.

    Unfortunately, as GeoServer seems to be only able to serve one top level feature of a specific type (e.g. LandCoverUnit), should someone want to serve data from multiple datasets of the same type then he or she would have to deploy as much GeoServer instances as there is datasets to be served via the WFS. Of course, there is the solution to serve only a single dataset via the WFS and the other via the pre-defined ATOM. 

    Best regards,
    Hrvoje

  • Lena Hallin-Pihlatie

    By Lena Hallin-Pihlatie

    Hi Hrvoje,

    You write "as GeoServer seems to be only able to serve one top level feature of a specific type (e.g. LandCoverUnit), should someone want to serve data from multiple datasets of the same type then he or she would have to deploy as much GeoServer instances as there is datasets to be served via the WFS"

    I'm not a WFS expert, but this is, as I see it, a real challenge for WFS production and maintenance, since the reality is as you say that you often want to share several datasets using the same application schema and in Geoserver you seem to be able to map to a specific application schema only once, without having to make a new GeoServer instance. For example, in the LC theme you may want to share datasets from different years using same application schema and in the PS theme you actually to my knowledge have to share both Protected sites (nationally designated areas) and Natura 200 sites using the same application schema...

    Is there any tool available for smooth mapping and WFS maintenance, without this "only map once restriction"?

    BR,

    Lena

     

  • Hrvoje Matijević

    By Hrvoje Matijević

    Hi Lena,

    My point exactly. To be precise, one can use a schema multiple times, but can only use each object class from that schema once per Geoserver instance. Should someone want mutliple datasets of an identical type to be served via separate WFS's, then she/he will need as much Geoserver instances as there is datasets to be served. How other available servers (ESRI, Degree) stand on this matter I do not know.

    Regards,
    Hrvoje

  • Lena Hallin-Pihlatie

    By Lena Hallin-Pihlatie

    Hi Hrvoje, all,

    @ Hrvoje: Thank you for describing this issue in a more precise way.

    @ All: Is there any tool available for smooth mapping and WFS maintenance, without this "only map once to each object class/type per instance restriction"? Are there perhaps already some concrete plans to do something about it?

    BR,

    Lena

  • Lena Hallin-Pihlatie

    By Lena Hallin-Pihlatie

    Dear all,

    I thought you might find this WFS software tool comparison and provision of multiple datasets discussion interesting and useful, even though it might not, not at least yet, provide a direct solution:

    https://themes.jrc.ec.europa.eu/discussion/view/88206/it-seems-that-there-is-no-fully-compliant-solution-to-serve-multiple-harmonised-datasets-trough-wfs-20?offset=10

    Best,

    Lena

  • Lena Hallin-Pihlatie

    By Lena Hallin-Pihlatie

    Hi,

    To my knowledge it is now possible to use 'isolated workspaces' now also for complex features and use only one GeoServer instance for the provision of several INSPIRE datasets. Last year you had to modify the namespace a bit though in order to get it to work. Correct me if I'm wrong and please let me know if you have an update on this.

    When I was looking in the GeoServer manual on the web I couldn't find any information on how to actually do this. If any one of you know where to find the instructions, could you please let me know.

    Many thanks in advance,

    Lena

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