The scope of the theme “Geographical grid systems” covers quadrilateral grids used for the indirect geo-referencing of themes with typically coarse resolution and wide (pan-European) geographical extent. The grid is two-dimensional and mainly used for Spatial Analysis or Reporting. A geographical grid is associated with predefined resolutions and a coding system for identifying individual cells.
Objectives
One method of storing spatial information with indirect position is by using geographical grids. Grids omit direct spatial reference and average the qualitative properties of the subject. This makes them powerful tools for harmonisation and reduction of the complexity of spatial datasets. Geographical grids are also effective communication means for reporting spatial variability of features.
Technically, grids for geographical data are predefined spatial reference structures composed of cells regular in shape or area. Cells are usually squares based on a given coordinate reference system but, in rare cases, they can be shaped differently, e.g. as hexagons.
There are many types of grids available for different purposes. Ideally, one grid that is useful for all purposes ought to be created but it is not possible for one grid to cover uniformly the whole of
Europe. Any type of grid will always have some disadvantages that disqualify it for certain use.
The following grid examples are presented to describe the difficulties in selection of a multipurpose grid.
Owner
The INSPIRE specification on Geographical grid 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 and the UK, all of them for many years involved in activities aiming to establish uniform georeferencing 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
INSPIRE Geographical grid systems form a geo-referencing framework for the themes where grids with fixed and unambiguously defined location of equal-area grid cells are needed. Mandating or recommending the use of these grid systems for individual INSPIRE themes or specific cross-theme applications is out of scope of this INSPIRE theme.
It is recognised that there is a need to enable grid referencing for regions outside of continental Europe, for example for overseas Member States (MS) territories. For these regions, MS are able to define their own grid, although it must follow the same principles as laid down for the Pan-European Grid and be documented according to ISO19100 standards.
Such MS defined grids will be based on 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. This follows the Requirement 2 of the Implementing Rule on Coordinate reference systems [INSPIRE-DS-CRS], i.e. compliant with the ITRS means that the system definition is based on the definition of the ITRS and there is a well-established and described relationship between both systems, according to ISO 19111:2007 Geographic Information – Spatial referencing by coordinates.
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.