The INSPIRE regulations provide a framework that describes how datasets that fall within specified categories should be published. This describes both how the data should be presented (data specifications) and how they should be accessed (view and download services – network services). In the UK over 200 datasets can now be accessed using these network services.
The INSPIRE regulations also reference another type of service, which are termed “Transformation Services”. We are aware we have not said much about these services, and that there is some uncertainty as to what data publishers should be doing about them. So the purpose of this article is to provide some clarification about what Transformation Services are, and how we are in the UK are dealing with these.
A series of data specifications define the data format, the data model and the Coordinate Reference System (CRS) that the data should be published in. Whilst the initial focus of our efforts has been on publishing data “as is”, the longer-term focus requires that all in-scope datasets are published to common specifications. The INSPIRE legislation sets a series of deadlines between now and 2020 for achieving this dependent on the category of dataset, with datasets which are created or significantly changed needing to meet these specifications now.
In INSPIRE terms, a “Transformation Service” is one which can be used to make a spatial dataset conformant with these INSPIRE data specifications. Put simply, a Transformation Service allows a dataset which doesn’t meet the data specifications to be transformed so that it does. As such, Transformation Services are different to other network services in that they support existing services which already publish data, rather than being a service in their own right.
Here in the UK we have investigated the need for Transformation Services, and have discussed our position with EU. Our position (which has been confirmed with EU, and is in line with the guidance cited above) is that there is no need to provide Transformation Services if existing services can be used to support transformation. This can be summarised as:
- Data Specification transformation. This is the process of taking an existing dataset and converting it to conform to an INSPIRE data specification. This will be done as part of a Data Publishers process of preparing data for publication. That is, it will be an internal process for the data publisher. There is no need for the data publisher to provide a publically-accessible network service to do this.
- Coordinate Reference System transformation. This is converting a dataset from one coordinate reference system (e.g. British National Grid) to an INSPIRE conformant one (e.g. ETRS89). This can be done as part of the process of preparing data for publication, as outlined above for data specification transformation. Alternatively it can be managed within an existing View or Download Services. Both WMS and WFS (standards used for View and Download Service respectively) support the concept of “on-the-fly” coordinate transformation, allowing a dataset that is stored in one CRS to be transformed to another as it is served to a user.
So to summarise. There is no requirement for a Data Publisher to implement a Transformation Service. Transformation of existing datasets to INSPIRE conformant specifications can be achieved either as part of a publishers production process, or by making use of capabilities that are already available in existing View and Download Services.