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Common Database on Designated Areas: Handling of European oversea territories and outermost regions in terms of the coordinate reference system

Hello everybody,

In the framework of the implementation of INSPIRE into the Common Database on Designated Areas (CDDA) for the EEA we’ve come into the problem of how overseas and outermost regions of European countries should be defined in terms of their coordinate reference system. For continental countries within Europe the EEA has used EPSG:3035 ETRS89-LAEA so far as it is used commonly for this geographical extent and is regarded as appropriate for this purpose. Countries reporting their designated areas have currently two options to deliver the data.

  • For areas inside Europe they have to use ETRS89-LAEA. As designated areas are highly related to the area extent this coordinate reference system is used, as it allows for direct area calculations.

  • But few Countries (particularly France and Denmark due to Greenland) are reporting designated areas far outside of Europe and the applicability of ETRS89-LAEA. For these regions the countries have to used WGS84 (EPSG:4326) so far. The problem is, that this reference system does not allow for area calculations comparable to the areas derived for Europe itself. To be able to calculate statistics and further analyse the protected areas we are thinking on how to solve this issue.

Is there some recommendation which reference system should be used or would it be more reasonable to use multiple specific systems depending on the regions the protected areas are located in? Maybe in other topics of INSPIRE this issue has also appeared and a solution/guideline was found.

Especially Greenland does have many extensive designated areas. Therefor it is important to obtain correct areas for statistical analysis. According to the ESPG registry ETRS89-LAEA is not applicable for Greenland.

So far we have two options for this problem:

1. Countries are asked to deliver their data in EPSG 3035 (continental parts) and 4326 (outside Europe) and then reproject the latter to some appropriate CRS for area calculation. (although I don’t think this is possible using only one projected coordinate reference system for all overseas)

2. Countries are asked to directly report in a suitable CRS. This would mean EEA would only accept EPSG 3035 for the majority of the countries respectively for all in terms of their continental data. For the specific cases like the French overseas the data has to be delivered in the projected CRS like UTM xx or whatever would be suitable. In most cases the countries should know best, which is the correct CRS. By this we would end up with a collection of European designated areas utilising multiple CRS. So it’s not possible to provide a CDDA dataset containing all protected areas in one.

I assume it will not be possible to find one appropriate reference system which is covering all regions but is still enabling us to calculate areas and spatially more explicit reference system for each region will be required, but as the overseas and other outermost regions are official territory of European countries, maybe this question has been discussed already in other contexts of INSPIRE.

Does anyone have further ideas or maybe experiences from other topics with this problem?

Thanks,

Christopher

  • Julián DELGADO

    By Julián DELGADO

    Dear Christopher, all

    We found a similar doubt than the European CDDA in the in the generation of INSPIRE Elevation data for overseas territories. After reading some INSPIRE specifications I detected that depending of the theme, there can be some particularities. I include this comment in this topic because I think that can be applied also in other INSPIRE theme, not only for Elevation.

    We are converting Canary Island elevation dataset from or national approved reference systems (REGCAN EPSG:4326 or Pico de las Nieves EPSG:4728) into INSPIRE. Unfortunately, the directive for overseas territories accepts none of them. In the EL specifications, in the grey-common pages for all themes, it is possible to read:

     

    IR Requirement (1.3.3(2))

    For the vertical component on land, the European Vertical Reference System (EVRS) shall be used to express gravity-related heights within its geographical scope. Other vertical reference systems related to the Earth gravity field shall be used to express gravity-related heights in areas that are outside the geographical scope of EVRS.

    IR Requirement (1.3.4)

    Exceptions, where other coordinate reference systems than those listed in 1.3.1, 1.3.2 (systems listed by Christopher) or 1.3.3 may be used, are:

    1. Other coordinate reference systems may be specified for specific spatial data themes in this Annex.

    2. For regions outside of continental Europe, Member States may define suitable coordinate reference systems.

    The geodetic codes and parameters needed to describe these coordinate reference systems and to allow conversion and transformation operations shall be documented and an identifier shall be created, according to EN ISO 19111 and ISO 19127.

     

    After that, I could mean that, many other reference systems could be used in INSPIRE for overseas territories, meanwhile and always, can be described them in terms of ISO 19111 and 1927.

    Some of you have found the similar situation than Christopher and myself? Maybe French, British or Portuguese colleagues have just face up with this INSPIRE topic.

    My best regards

    Julián

    IGN Spain

  • Jordi ESCRIU

    Dear Christopher,

    Many thanks for your question!

    Having read your issue, you have mainly to cover the following needs / goals:

    1. Calculate the area for each Designated Area with the aim to perform calculations and compare it with other instances of Designated Area.

    2. Publish a data set with all European Designated Areas (European CDDA).

    As Julián exemplified with the Elevation theme, in the context of INSPIRE Member States may decide which CRS shall be used for overseas territories (i.e. outside the scope of ETRS89 / outside continental Europe) - as stated in Annex II - Section 1.3.4 of the Implementing Rule of Interoperability of Spatial Data Sets and Services. These CRS shall have an identifier in a CRS registry and be properly documented, as highlighted above.

    In my view...

    It is quite unlikely that these CRS proposed by MS are based on an equal-area projections. In this situation, the different Designated Areas would not be comparable - the area of the polygons may suffer for area distortions, which would be different in each MS data set. Therefore, Goal 1 could not be achieved.

    Regarding Goal 2, the different CRS proposed by MS for overseas territories may be based for sure on different datum and following a wide range of projections. Again, a goal impossible to be achieved.

    Just wondering...

    Would it be a solution to:

    - Ask the corresponding INSPIRE theme to include in the data model an 'area' attribute for Designated Areas and similar spatial object types, for which it is important to make comparisons.

    - Make any comparisons and calculations based on the value of this attribute (Goal 1).

    - Transform all the data from different MS to a common / global CRS, in order to visualize all data together (Goal 2).

    Please, provide any other inputs or ideas you may have!

    Jordi

  • Iurie MAXIM

    Dear all,

    I do not think that the "area" must be added as an attribute for Protected Sites Data Theme as this can be derived from the Geometry of the poligon trough a WPS - Web Procesing Service (invoke service).

    Similar for many other atributes within CDDA than can be derived by computation or intersection with other features types.

    Entire CDDA database can be provided trough Protected Sites Data Scheme (PS). All the missing attributes can be derived.

    I am sure that no other attribute then those that already exist in the PS data scheme are not needed by EEA and can be computed or derived.

    I know about the discutions held regarding the Legal Surface of Protected Area versus Computed Surface of Protected Area and that some  Protected Areas can be represented as points within INSPIRE (so no geometry can be computed).

    What I want to say is that actualy EEA must consider to change the CDDA to follow the INSPIRE principles rather than adding a new scheme within the PS for CDDA. I saw that strangely the proposed CDDA scheme for a potential use within INSPIRE was asking even for the IUCN Category to pe provided with roman numers (I, II, .. V..) even if this value is already provided in INSPIRE in lowerCamelCase (ie: nationalPark).

    As regarding the geometry of the Protected Sites, they can be provided in different CRS in the same wfs:FeatureCollection because the CRS is provided for each ps:ProtectedSite wfs:member.

    In any case, I think that the CDDA for the EU members must be delivered trough a WPS by making an union of all PS datasets under IUCN data Scheme provided within INSPIRE trough download services. This is because the MS will permanently keep up to date their PS data as this is required by INSPIRE. If CDDA will not be made trough a WPS then it will not be up to date.

    I can explain how the CDDA atributes are mapped to PS, which CCDA attributes need to disapear as they can be computed or are obsolete and that only LifeSpanVersion must be added to PS.

    It is not true at all that "By this we would end up with a collection of European designated areas utilising multiple CRS. So it’s not possible to provide a CDDA dataset containing all protected areas in one". It is corect for ESRI shapefile or geodatabase, but is not correct for GML as required by INSPIRE.

    Here you may see an example how to encode different CRS (3035 and 3034) for different features:

    <wfs:member>
    <ps:ProtectedSite gml:id="RONPA0001">
    <ps:geometry>
    <gml:MultiSurface gml:id="Geom_RONPA0351_2016-02-29" srsName="urn:ogc:def:crs:EPSG::3035">...</gml:MultiSurface>
    ...
    </ps:geometry>
    ...
    </wfs:member>
    <wfs:member>
    <ps:ProtectedSite gml:id="ESNPA0001">
    <ps:geometry>
    <gml:MultiSurface gml:id="Geom_ENNPA0011_2015-01-03" srsName="urn:ogc:def:crs:EPSG::3034">...</gml:MultiSurface>
    ...
    </ps:geometry>
    ...

    </wfs:member>

    It is even possible to provide point and poligon geometries for the same feature type within the same wfs:FeatureCollection (dataset).

    Any comments would be highly apreciated.

    Best regards,

    Iurie Maxim

     

  • Jordi ESCRIU

    Dear Christopher,

    Let us know if your question is covered by Iurie's answer.

    Otherwise, please provide comments to Iurie's post or new inputs.

    Thank you

    Jordi

  • Jordi ESCRIU

    Since there are no new inputs, i consider that the question is successfully answered.

    Hence, i proceed to close this discussion topic.

    Please, feel free to send me a message throgu the platform if  any of you want to re-open it.

    Jordi

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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