Harmonizing and implementing the Dutch Cadastral Parcels (PDOK)

  • Author
    Jeroen HOGEBOOM
  • Post date: 
    19 Feb 2016
  • Last modified: 
    05 Oct 2016
  • Country: 
    Netherlands
  • Themes: 
    • Cadastral parcels
  • Content needs review

    PDOK (a Dutch service provider) delivers multiple view and download services for various Dutch data providers. One of these data providers is the national Dutch cadaster, which maintains cadastral data as well as other datasets.

    To follow the INSPIRE roadmap, a few years ago the Cadastre ordered PDOK to provide a dataset which (among other data objects) maintains the Cadastral Parcels object (INSPIRE theme). Initially the provided data was modelled “as/is” which means the data was not harmonized but provided in a specific Cadastral (non-INSPIRE) datamodel. This was the first step described by the INSPIRE roadmap. The as/is data was (is) available through a WMS and WFS and met the requirements described by the INSPIRE Quality of service rules.

    PDOK is an agile scrum-team consisting of multiple software developers and geo-data experts. Currently, a mature software delivery infrastructure and process is already in place. We uses a multiple geoserver webservers on top of a PostGIS 1.5.2 database. A number of Geoserver webservers were setup specifically for INSPIRE “as/is” webservices. This was done using the INSPIRE extension for Geoserver (http://docs.geoserver.org/stable/en/user/extensions/INSPIRE/index.html) as well as other tools.

    To enforce INSPIRE compliancy a testing framework is used. This framework is run by PDOK. This is done periodically as well as with new services. This framework is implemented by Geonovum (see http://www.geonovum.nl/validator-INSPIRE-view-en-downloadservices).

    Every year PDOK reports to its data providers a conformity of INSPIRE compliancy of each webservice as well as delivering a report describing performance, availability, etc. (as described by the TG).

    Not that long ago the Dutch Cadastre requested PDOK to follow up to the next step of the INSPIRE roadmap which means filter only the Cadastral Parcel (out of the as/is dataset) and deliver the Cadastral Parcels via the INSPIRE harmonized regulation. The following sections will describe the steps taken to implement this. Furthermore, it describes the maintenance and quality assurance measures (regression) put in place in order to fulfil the non-functional requirements specified by INSPIRE.

    As input, the Dutch Cadastre provided a mapping specification describing how the non-INSPIRE data maps to harmonized data, along with the Cadastral Parcel data defined in the current (Dutch) format. The desired output were working map/ features (WMS/ WFS) services which makes the INSPIRE harmonized Cadastral Parcel data available to the public. In short, our objective was to realize both the WMS and WFS for INSPIRE CP and come up with an generic IT solution which could also be used for harmonizing and serving other INSPIRE themes. Moreover, we discuss tools used to monitor and report INSPIRE compliancy (service quality, availability, performance etc.)

    Steps

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    PDOK is not responsible for the mapping but a few sessions between PDOK and the data provider where needed to finalize a mapping which is usable by PDOK as a service provider and the Cadastre as the data provider (appointed party for fulfilling the INSPIRE theme). PDOK will contact the data provider to see if it's possible to deliver this information.

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    The existing, non-INSPIRE geometries are defined in the Dutch "Amersfoort/RD new" projection (SRID: 28992). INSPIRE requires the geometries to be defined in the ETRS 89 projection.

    There were multiple approaches for doing this:

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    After the implementation was complete, the result was verified both by PDOK (service provider) as well as the Cadastre (data provider).

    Within PDOK, we checked the NAPTRANS transformations against hand-made calculations to verify the implementation was correct. Also we ran the ETF tool to check the resulting WFS and WMS services.

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    PDOK has tooling in order to ensure the quality-of-service requirements. We have implemented the ETF validator tool from Geonovum (www.geonovum.nl) in order to be able to test WMS, WFS and Atom services and verify they meet the INSPIRE requirements for View and Download Services. This tool is ran in-house and we run this tool automatically every week.