Geographical grids are an agreed, defined and harmonised grid net for Pan-Europe with standardised location and size of grid cells. Examples of cell sizes could be 10x10 m, 100x100 m, 1x1 km, 16x16 km. A good candidate for the INSPIRE-focused Pan-European grid has been proposed as a result of the Workshop on European Reference Grids.
The grid - proposed as Pan_European standard - is based on the ETRS89 Lambert Azimuthal Equal Area coordinate reference system with the centre of the projection at the point N 52o, E 10o. The grid is defined as hierarchical one in metric coordinates in power of 10.
The detail description of the proposed grid is available at the Proceedings of the Workshop on the European Reference Grids, EUR Report 21494 EN, 2005. The Proposal for a European Grid System is presented from page 39 to 46 of that document.
Other grids could be also used, however they need a lot of harmonisation work, as well as a number of conversion tools. Some international organisations, like WMO, perform their operations, using their own and purpose-oriented grid construction.