More Information about MEUSIS: Panagos, P., Liedekerke, M.V., Montanarella, L. Multi-scale European Soil Information System (MEUSIS): a multi-scale method to derive soil indicators. Computational Geosciences: Volume 15, Issue 3 (2011), Page 463-475
The Technical MEUSIS definition requires the analysis of the following concepts:
- Common Coordinate Reference System and the point of origin
- Spatial Resolution
- Spatial Hierarchy: Reference Grids
- Attribute Level Hierarchy: Data Exchange Format
Common Coordinate Reference System and the Point of Origin
ETRS89 Lambert Azimuthal Equal Area CRS (ETRS-LAEA) .
Grid Origin: 4.321.000,0 m west of the projection centre point (52N, 10 E), and 3.210.000,0 m south of projection centre point (52N 10 E)
Four geographical reference grids have been proposed on different spatial resolution levels. Geographical reference grids have been set as follows:
- Coarser Resolution Grid: 100km x 100km,
- Medium Coarse Resolution Grid: 10km x 10km,
- Medium Fine Resolution Grid : 5km x 5km
- Fine Resolution Grid: 1km x 1km.
The 100km x 100km, 10km x 10km, 5km x 5km and 1km x 1km reference grids are spatially arranged in the way so that each pixel of higher hierarchical level can be represented by the set of pixels coming from lower hierarchical levels. For example the 10km x 10km grid can be spatially represented by the set of four 5km x 5km or one hundred 1km x 1km pixels. Similarly one 5km x 5km grid pixel can be represented by the set of twenty five 1km x 1km grid pixels. Constructed in this way, MEUSIS 100km x 100km, 10km x 10km, 5km x 5km and 1km x 1km reference grids constitute a system of spatially nested hierarchical grids .
Each of the 100km x 100km, 10km x 10km, 5km x 5km and 1km x 1km grid cell is in geographical database identified by the aid of the unique identification number (alphanumerical string) which is derived in accordance with proposed coding system for European geographical reference grids. The Grid cell labels are defined with specific rules and consist of two parts (longitude, latitude) concatenated by a "_". The number of digits depends on the Reference Grid:
- 2 digits for the 100km x 100km,
- 3 digits for the 10km x 10km,
- 4 digits for the 5km x 5km
- 3 digits plus the direction (NW - northwest, NE - northeast, SW - southwest, SE - southeast, e.g. 123_123NE) for the 5km x 5km
Spatial Hierarchy: Reference Grids
In the context of INSPIRE it is expected that exchange of soil related data at regional, national and European level will happen in a grid- or raster-like fashion. The basis for such work is the availability of standard or reference grids in a common co-ordinate system with fixed cell sizes and common cell coding. MEUSIS will represent information on soils in predefined geographical grid of regular spatial elements (pixels) referred to as spatial reference grid in order to avoid most of disadvantages of vector representation of soil data. Following the INSPIRE principles described in the European Commission proposal for INSPIRE - SEC(2004)980, a harmonised hierarchical geographic grid (covering whole Europe) with a common point of origin using the ETRS89 Lamberth Azimuthal Equal Area geographic co-ordinate reference system (ETRS-LAEA) has been selected as the spatial reference grid for MEUSIS.
The European Commission has implemented the proposal adopted in the 1st European Reference Grids Workshop and created a number of reference grids for the European Union 25 countries, with cell sizes of 1km and 10km. Each cell carries a unique cell_id identifier compliant to the grid proposal. All grids are in the ESRI polygon shapefile format. The co-ordinate system is the ETRS LAEA system proposed by INSPIRE and is embedded in the shapefiles. Download the proposed Grids (listed also in National Level) which may fit also for other data exchange purposes in various environmental domains (Air, Water, etc).
Attribute Level Hierarchy: Data Exchange Format
From technical point-of-view the data exchange format represents an internal-structured relational database which is coupled to the MEUSIS geo-referenced data (spatial reference grids). The whole set of tables and the relationships between them define the data exchange format. Within the MEUSIS database each spatial hierarchical level (100km x 100km, 10km x 10km, 5km x 5 km or 1km x 1km) is described by the separate set of data tables. The reference grid on a specific spatial resolution level together with the data exchange format represent an element of MEUSIS database.
Each of the pixels in the various spatial hierarchical levels has a unique identifier which is unique and represents the Primary Key in the MEUSIS database. The identifier gets the value according to the rules described in the Labeling.
The MEUSIS meta-information is an important option for the metadata of the MEUSIS data. As meta-information it is considered:
- the detailed information on used data
- the interpretation of methodologies
- the important information on used analytical methodologies (or the way of the values transformation if not in accordance with international standards).