Technical details of Corine Land Cover

The Corine Land Cover 2012 (CLC 2012) project in Ireland forms part of the update of land cover maps for the whole of Europe and is co-ordinated by the European Environment Agency.

Ireland previously participated in the Corine 1990 land cover mapping project, and the Corine 2000 and 2006 was managed by the Environmental Protection Agency (EPA) in Ireland.

The 2006 project was developed for the EPA by ERA-Maptec under the supervision of a Steering Committee. The 2012 dataset is being produced ‘in-house’ by land cover and remote sensing experts within the EPA.

The Corine Land Cover inventory is based on satellite images as the primary information source. The use of earth observation data has important implications on the nomenclature, mapping unit and scale. For the 2012 data series additional GIS vector land cover datasets will be used to aid the classification process.

Spatial and spectral resolutions

Spatial and spectral resolution determines the capability of the satellite sensor to capture objects on the earth surface. Satellite sensors cannot always capture all the different objects on the earth's surface. They can only be distinguished if they are larger than the sensors' pixel size and spectrally different from surrounding objects.

A spatial resolution of 10x10 m (SPOT Panchromatic) to 80x80 m (Landsat MSS) was used for CLC 2000. The Landsat-7 satellite was not available for CLC2006 so a new source of satellite imagery was used. A collaboration with the European Space Agency (ESA) and GMES provided two new satellites, SPOT-4 and IRS P6. The same combination of satellite imagery is being used in the 2012 series.

Spatial coverage of these two sensors is very similar to the Landsat-7. Slight technical differences occurred in the image colour. These were compensated for by the application of specific band combinations.

The satellite sensors determine not only the scale of work, but also the scale of the cartographic products.

The scale of all output products of CLC is set to 1:100000, facilitating the detection of essential features of the terrain by means of satellite images (Spot, Landsat MSS, TM and IRS) and their representation.

Minimum mapping unit

The minimum mapping unit, e.g., the smallest cartographic unit mapped, is linked to the choice of scale. It was fixed at 25 hectares for all Corine Land Cover datasets and 5 hectares for Corine Land Cover Change datasets. Linear features smaller than 100m wide are not considered and generalised.

The size of the smallest unit mapped is a compromise between the level of detail captured by visual interpretation of MSS data, the legibility of the printed maps and a reasonable tradeoff between project operation cost and provision of land cover information (EEA & ETC/LC, 1999).

The consequence of this setting is that even if the interpreter is able to distinguish single features, such as grassland or arable land, each covering an area less that 25 hectares for Corine Land Cover datasets and 5 hectares for Corine Land Cover Change datasets, they are grouped and categorised as a mixed class (for example heterogeneous agricultural areas).

The relationship of satellite images, scale and minimum mapping unit are complex and may be difficult to understand, but they are important when assessing the quality of the data.  The technical and cartographic specifications have consequences on the quantification of structural properties and characterisation of the countryside.

Features smaller than 25 hectares for Corine Land Cover datasets and 5 hectares for Corine Land Cover Change datasets or 100 metres (such as hedgerows) are not considered in the CLC inventory. These elements represent important structural elements of certain landscapes, essential in ecological terms and an inherent integrated part of the physiognomy and the visual perception. In this sense the results presented give only a broad picture of the countryside.

Nomenclature

The nomenclature contains some mixed classes (e.g. 2.4: "heterogeneous agricultural classes") characterising areas composed of small features or land cover classes which do not exceed an area of 25 hectares and/or which are not easily distinguishable in the satellite images.

These classes already contain structural information, but within the calculation this class is assumed to be a homogeneous class concerning the appearance.

codeCLC (level 2)codeAggregation
1.1 Urban fabric 1 Artificial surfaces
1.2 Industrial, commercial and transport units 1 Artificial surfaces
1.3 Mine, dump and construction sites 1 Artificial surfaces
1.4 Artificial, non-agricultural vegetated areas 1 Artificial surfaces
2.1 Arable land 2 Arable land
2.2 Permanent crops 3 Permanent crops
2.3 Pastures 4 Pastures
2.4 Heterogeneous agricultural areas 5 Heterogeneous agricultural areas
3.1 Forests 6 Forests
3.3 Open spaces with little or no vegetation 7 Mineral surfaces 
3.2 Shrub and/or herbaceous vegetation associations 8 Natural vegetation
4.1 Inland wetlands 8 Natural vegetation
4.2 Coastal wetlands 8 Natural vegetation
5.1 Continental waters 9 Water bodies

Learn more

Download Irelands Corine Land Cover documents including the legend colours for data sets and the Corine Update Guide.

The European CLC2006 Technical Guidelines, Report No 17/2007 prepared by the EEA.

Corine Land Cover Update 2000, Technical Guidelines, prepared by the European Environmnet Agency and the EC Joint Research Commission

Corine Land Cover Technical Guide, addendum 2000, A report prepared by the European Topic Centre on Land Cover and Phare Topic Link on Land Cover to support the land cover monitoring activities of the European Environment Agency (EEA Multi-annual Work Programme 1998-2002, project 1.3.5 Land Cover).