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How to implement tiling / model mosaic elements, coverages and coverage aggregations in GMLCOV files

During the INSPIRE-KEN & TC #3 Workshop on Transformation of Coverage-based Data Themes and WCS celebrated in Barcelona at the end of September, different data transformation / encoding experiences were presented that show doubts / questions about:

  • How to implement tiling within the GMLCOV files. 
  • How to model mosaic elements, coverages and coverage aggregations within the GMLCOV files.

For example:

  • Provide multiple rangeSets within the same GMLCOV file?
  • construct more complex structures using feature collection / feature members?

Please, have a look at the following experiences and provide us with your opinion / input about the best option to use (at its correctness):

Experience from Saxony

Workshop Coverages and WCS - Experience data transformation - Saxony / con terra

Experience from IGN-Spain

Workshop Coverages and WCS - Experience data transformation - IGN-Spain

  • Sören Dupke

    In the example from the Saxony the dataset consist of 2x2km tiles. The overall dataset is 230 GB of data. Currently the data is provided through ATOM feeds with one OrthoimageCoverage GML file per tile. This is clearly not exactly compliant with the data specification as tiling is not reflected in the data model and also not in the encoding part. The situation is similar as described in example E.2.6 in the current data specification.

     Figure 21 from Example E.2.6

    As the example shows the data model still requires the creation of one single OrthoimageCoverage instance for this data set. This is problematic since the rangeSet of an Orthoimage coverage can only contain a single gml:File object and creating a single geotiff file with 230GB is obviously not an option.  

    Using a WCS request link inside the rangeSet as it was discussed at the KEN workshop is also not an option since the approach uses an gml:File element in the rangeSet as well and therefore would require to point to an WCS request that delivers the complete dataset. 

    So the question is how can such a big coverage be encoded? 

  • Jordi ESCRIU

    During the past INSPIRE Conference 2016 in Barcelona, Thematic Cluster #3 organized the Workshop "Implementation and potential of INSPIRE coverage data and WCS" (celebrated on 30th September 2016), where all the aspects included in this topic were discussed.

    The minutes and results of the Workshop in Barcelona are now available here:

    https://themes.jrc.ec.europa.eu/pages/view/115418/results-from-the-ws-on-implementation-and-potential-of-inspire-coverage-data-and-wcs

    For clarity and allowing a clear and smooth run of the discussions in the workshop, all the mentioned aspects were splitted in separate / different topics.

    As a result, new separate discussion threads have been open in the platform:

    • How to deal with huge volume of coverage data (Issue 1 in the Workshop in Barcelona / INSPIRE Conference 2016)
    • Case 1. Delivery through Predefined datasets - Discussion item closed (open for comments): Consolidated results and recommendations agreed by the cluster are stated in this Dedicated page.
    • Case 2. Delivery through WCS - Discussion item closed (open for comments): Consolidated results and recommendations agreed by the cluster are stated in this Dedicated page.
    • How to implement the concept of coverage aggregation (Issue 2 in the Workshop in Barcelona / INSPIRE Conference 2016).

    The discussion is more advanced but open yet in the following thread: How to implement the concept of coverage aggregation.

    • How to implement the concept of mosaicking (Issue 3 in the Workshop in Barcelona / INSPIRE Conference 2016).

    The discussion is more advanced but open yet in the following thread: How to implement the concept of mosaicking.

    As the result, the present thread may be closed.

    Please, actively participate in the new discussion threads!

  • Jordi ESCRIU

    Dear members of the cluster,

    Find below a recent presentation in the INSPIRE Conference 2017 in Strasbourg - "Pushing implementation of European coverage data and services forward", summarizing the main challenges and issues related to INSPIRE coverage data implementation identified in the context of our cluster:

    https://themes.jrc.ec.europa.eu/file/view/153918/pushing-implementation-of-european-coverage-data-and-services-forward

    It also explains proposals (in draft status) to solve such issues and align implementation of INSPIRE Coverage data to the one foreseen in OGC (OGC-standard coverage data).

    The proposals would be properly updated, explained and discussed in an Online Webinar of the cluster to be scheduled by early or mid-October.

    Happy to count with your collaboration to get consensus in the solutions proposed.

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Elevation, Ortho & Grids

Elevation, Ortho & Grids

INSPIRE Thematic Cluster Elevation, Orthoimagery, Reference systems, Geographical grids - Join this group to share your knowkledge, learn and collaborate in solving issues related to the Elevation, Orthoimagery, Reference systems and Geographical grids themes