The INSPIRE theme Coordinate reference systems (CRS) provides a harmonised specification for uniquely referencing spatial information. This document also provides the specification for the map projections to be used for georeferencing the spatial information in plane coordinates.
Objectives
The scope of the theme Coordinate reference systems covers the Geodetic Coordinate Reference Systems (CRS) required for uniquely referencing spatial information in space as a set of coordinates (X, Y, Z) and/or latitude, longitude and height.
This is achieved by defining a geodetic datum to express the geographical coordinate’s latitude, longitude (horizontal component) and a vertical datum to express height (vertical component).
The set of coordinates (Latitude, Longitude, Ellipsoidal height) can be derived from the space set of coordinates (X, Y, Z) using a suitable reference ellipsoid. The GRS80 ellipsoid will be adopted for this purpose.
For the three-dimensional and two-dimensional coordinate reference systems and the horizontal component of compound coordinate reference systems used for making available the INSPIRE spatial data sets available, the datum shall be the datum of the European Terrestrial Reference
System 1989 (ETRS89) in areas within its geographical scope, or the datum of the International Terrestrial Reference System (ITRS) or other geodetic coordinate reference systems compliant with ITRS in areas that are outside the geographical scope of ETRS89. Compliant with the ITRS means that the system definition is based on the definition of the ITRS and there is a well-documented relationship between both systems, according to EN ISO 19111. 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.
For the vertical component in the free atmosphere, barometric pressure, converted to height using ISO 2533:1975 International Standard Atmosphere shall be used.
Owner
The INSPIRE specification on Coordinate reference systems has been prepared following the participative principle of a consensus building process. The stakeholders, based on their registration as a Spatial Data Interest Community (SDIC) or a Legally Mandated Organisation (LMO) had the opportunity to bring forward user requirements and reference materials, propose experts for the specification development, and participate in the review of the data specifications.
The Thematic Working Group responsible for the specification development was composed of geodetic and mapping experts coming from Portugal, Slovenia, France, Germany, Italy, Sweden, the UK and the Netherlands, all of them for many years involved in activities aiming to establish uniform geo-referencing within Europe. Due to the close links between and the special technical nature of the two themes of Coordinate reference systems and Geographical grid systems, the specifications of both themes were developed by one thematic working group.
Long description
The mandated CRS can be used for any kind of information/resolution/accuracy; the resolution and accuracy of data are out of scope of the theme CRS.
For data sets with low positional accuracy, the original CRS of the data set can sometimes be considered equivalent to the mandated CRS. It is recommended that the data set provider consults the experts in the Member States (MS) to evaluate the need to transform the data sets from the original CRS to the mandated CRS.
The decision for the maintenance of the data sets in its original CRS or in the mandated CRS will be taken according to the MS and the INSPIRE regulations.
The accuracy of the data sets resulting from transformations and conversion formulas are out of scope of the theme CRS. The accuracy of the data sets must be documented by the data set provider according to all the aspects that contribute to it, namely the original data accuracy and the accuracy of the conversions, transformations and other aspects involved with the management of the data.
There are themes for which data are expressed in linear systems for the horizontal component or on non-length-based vertical systems like pressure, density, for the vertical component. This kind of referencing is parametric.
In general the referencing by parameters is out of scope of the theme CRS. It is recommended to associate the parameters with the specific data according to ISO 19111.
However for data measured in the free atmosphere or free ocean, parametric references using barometric pressure converted to height are adopted for INSPIRE within the CRS.
Where more general parametric reference systems are used this is out of scope, but it is recommended that they should be appropriately specified and referenced.
There are themes that may require temporal references. Temporal reference systems are also out of scope of the theme CRS.
Known implementation
The whole known implementation of Inspire is available at:
http://inspire.ec.europa.eu/index.cfm/pageid/42
History / Key milestones
The Directive 2007/2/EC of the European Parliament and of the Council adopted on 14 March 2007 aims at establishing an Infrastructure for Spatial Information in the European Community (INSPIRE) for environmental policies, or policies and activities that have an impact on the environment.