CHAPTER 4 EUROPEAN LAND COVER MAPPING – THE …unique land cover and land cover change database has triggered a wealth of downstream applications in the area of environment, agriculture

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CHAPTER 4

EUROPEAN LAND COVER MAPPING – THE CORINE EXPERIENCE

Stefan Kleeschulte1, Gyorgy Büttner2

1 GeoVille Environmental Services Sàrl, Luxembourg and ETC LUSI# 2 FÖMI, Budapest, Hungary and ETC/TE# # European Topic Centre on Land Use and Spatial Information, Universitat Autònoma de Barcelona, Spain (http://terrestrial.eionet.europa.eu/)

ABSTRACT

The objective of this article was to provide the participants of the North American Land Cover Sum-mit with information about continental wide land cover mapping projects from outside the United States, Canada and Mexico. The article presents the European CORINE Land Cover experience of the last 20 years. CORINE Land Cover (CLC) marks a milestone in European land cover mapping and monitoring at the scale of 1:100.000. Started as one part of a larger programme for the Co-ordination of Information on the Environment (CORINE) in 1985, the land cover project has extended from just a few countries to currently twenty-nine (finished, several other ones in progress) European countries, a time series on land cover changes from 1990 to 2000. A second update of the database for the refer-ence year 2006 and with 38 participating countries is currently ongoing. The public availability of this unique land cover and land cover change database has triggered a wealth of downstream applications in the area of environment, agriculture and forestry as well as research and education, transport, and physical planning. The update of the database for the reference year 2006 is part of the programme on Global Monitoring for Environment and Security (GMES), the European contribution to the Global Earth Observation System of Systems (GEOSS).

Key words: Land cover, land cover change, Europe, CORINE, CLC, GMES

BACKGROUND

The objective of the European Environment Agency (EEA) is to provide policy makers and the

interested public with targeted, timely and relevant environmental information in order to support

sustainable development. Regarding land cover, EEA aims to provide those responsible for and inter-

NORTH AMERICA LAND COVER SUMMIT32

ested in European policy on the environment with qualitative and quantitative land cover information,

which is consistent and comparable across the continent. As part of the EEA mandate, the CORINE

Land Cover (CLC) database initiated by the European Commission (EC) in 1985 should be further

maintained and regularly updated. Consistent geo-referenced land cover information has been identi-

fied by different national and European policies as a key requirement for integrated environmental

assessment.

SPECIfICATIONS AND METHODOLOGy

From 1985 to 1990, the European Commission implemented the CORINE Programme (Co-ordi-

nation of Information on the Environment) (Heymann et.al. 1994). During this period, an information

system on the state of the European environment was created and nomenclatures and methodologies

were developed and agreed at European Union (EU) level. The first European-wide land cover inven-

tory (also referred to as CLC90) was realised successively in some 25 countries between 1986 and

1998.

In order to satisfy the growing demand for up-to-date land cover information, the EEA and the

Joint Research Centre (JRC) of the European Commission in 1999 jointly launched the update of the

CLC database. This project consisted of two components:

IMAGE2000: a snapshot of Landsat 7 Enhanced Thematic Mapper (ETM) satellite images of

the European territory (+/- one year) as the basis of the land cover map, including all services related

to satellite image acquisition, ortho-rectification and production of European and national image mo-

saic.

CLC2000: the production of a new land cover database, including the correction of the first inven-

tory (CLC90), the detection of land cover changes (based on CLC90, IMAGE90 and IMAGE2000)

and the creation of a seamless European database from the individual national data sets.

The CLC2000 project largely built on the experiences of the first inventory and tried to address

and improve the main bottlenecks identified for the CLC90 database. Table 1 provides an overview

of the main characteristics of the two inventories and the improvements made with CLC2000. Main

33EUROPEAN LAND COVER MAPPING

CLC90 CLC2000

Organisation Individual countries producing independently and being added

successively

Coordinated production for 29 countries

Time consistency of country data sets 1986-1998 2000 +/- 1 yearImproved geometric accuracy:- satellite images:- CLC data:

50 m100 m

25 mbetter than 100 m

Thematic accuracy 85%Not validated at European level 87% +/- 0.8%

Project duration 10 years 4 years

Data policy No common data policy Dissemination policy agreed from the start

Table 1: Comparison of main characteristics of CLC90 and CLC2000

achievements are the coordinated approach within twenty-nine European countries (European Union

– EU25, Liechtenstein, Bulgaria, Croatia, and Romania – see Figure 1) a common reference date, a

standard methodology and a common data policy, allowing full public access to the CLC2000 prod-

ucts (i.e. wall-to-wall land cover database, land cover changes, improved CLC90). Currently the data-

base is being extended to Iceland, Norway, Switzerland, Turkey, Serbia, and Montenegro for the same

reference year.

The standard approach to producing CLC is based on computer assisted visual interpretation of

the ortho-rectified satellite images offered by IMAGE2000 according to the agreed CLC methodol-

ogy (Perdigão, V., Annoni, A., 1997 and EEA-ETC/TE, 2002) providing a vector database at scale

1:100.000 with a minimum mapping unit of 25 ha. The standard CLC nomenclature includes forty-

four classes in three hierarchical levels (see also Table 2). The project is implemented in a decentral-

ised approach in the EEA member counties, i.e. each country produces the national database contribut-

ing specific regional knowledge and building a national land cover mapping capacity. The individual

country data sets are later joined into one seamless geographic information system (GIS) layer, includ-

ing the matching of land cover objects (polygons) across borders.

One of the most important innovations of CLC2000 is the provision of land cover change informa-

tion. The mapped changes represent real land cover evolution, not seasonal differences or phenological


Figure 1: Coverage of C

LC2000


LEVEL 1 LEVEL 2 LEVEL 31. ARTIFICIAL

SURFACES1.1. Urban fabric

1.2. Industrial, commercial and transport units

1.3. Mine, dump and construction sites

1.4. Artificial, non-agricultural vegetated areas

1.1.1. Continuous urban fabric1.1.2. Discontinuous urban fabric1.2.1. Industrial or commercial units1.2.2. Road and rail networks and associated land1.2.3. Port areas1.2.4. Airports1.3.1. Mineral extraction sites1.3.2. Dump sites1.3.3. Construction sites1.4.1. Green urban areas1.4.2. Sport and leisure facilities

2. AGRI-CULTURAL AREAS

2.1. Arable land

2.2. Permanent crops

2.3. Pastures2.4. Heterogeneous agricultural areas

2.1.1. Non-irrigated arable land2.1.2. Permanently irrigated land2.1.3. Rice fields2.2.1. Vineyards2.2.2. Fruit trees and berry plantations2.2.3. Olive groves2.3.1. Pastures2.4.1. Annual crops associated with permanent

crops2.4.2. Complex cultivation patterns

2.4.3. Land principally occupied by agriculture,

with significant areas of natural vegetation2.4.4. Agro-forestry areas

3. FOREST AND SEMI-NATURAL AREAS

3.1. Forests

3.2. Scrub and/or herbaceous associations

3.3. Open spaces with little or no vegetation

3.1.1. Broad-leaved forest3.1.2. Coniferous forest3.1.3. Mixed forest3.2.1. Natural grassland3.2.2. Moors and heathland3.2.3. Sclerophyllous vegetation3.2.4. Transitional woodland-scrub3.3.1. Beaches, dunes, sands3.3.2. Bare rocks3.3.3. Sparsely vegetated areas3.3.4. Burnt areas3.3.5. Glaciers and perpetual snow

4. WETLANDS 4.1. Inland wetlands

4.2. Marine wetlands

4.1.1. Inland marshes4.1.2. Peat bogs4.2.1. Salt marshes4.2.2. Salines4.2.3. Intertidal flats

5. WATER BODIES 5.1. Inland waters

5.2. Marine waters

5.1.1. Water courses5.1.2. Water bodies5.2.1. Coastal lagoons5.2.2. Estuaries5.2.3. Sea and ocean

Table 2: Standard CLC nomenclature


development stages of vegetation or different interpretations of the same object, but the process does

not completely prevent these issues providing false positive and negative changes. The land cover

change is interpreted as a categorical change, when one land cover class or its part(s) was a replaced

by another land cover class(-es). The threshold for detection of changes is set to five hectares in order

not to loose many significant, but small scale changes. Details of the CLC2000 project are available

from Feranec et al, 2007. Looking to the main net changes urban areas have increased in Europe by

5 percent (870.000 ha) over the last decade (1990 to 2000), while agricultural areas have suffered a

loss of a similar amount of total area. About two thirds of these agricultural areas were converted to

artificial surfaces while almost one third was converted to forestland.

CLC VALIDATION

After its completion the seamless European CLC2000 database has been validated with the help

of LUCAS data. The European Land Use/Cover Area frame statistical Survey (LUCAS) (European

Commission – JRC, 2002) is a project managed by Eurostat, the statistical office of the European Com-

mission. Its main purpose is to provide harmonised information on the agri-environment for Europe.

LUCAS data is the only information that is available for a European wide validation of CLC2000,

which fulfils the criteria of validation data: being of high geometric accuracy, having a mostly coinci-

dent acquisition window and not having been used in the production process of the data to be validat-

ed. LUCAS data exist for approximately 10.000 locations in eighteen European countries and records

independent land cover (fifty-seven classes) and land use (fourteen classes) information for each of the

observations as well as landscape photographs in four compass directions (see Table 3and Table 4).

The validation of the CLC2000 database was based on the re-interpretation of the field photo-

graphs in combination with the LUCAS codes and the original satellite images. The consideration

of the field photographs had the advantage of being able to consider the different minimum mapping

units respectively observation units of CLC (25 ha) and LUCAS (circle of 3 m).

The result of the reinterpretation approach was that the total reliability of CLC2000 is 87.0 ± 0.8

percent, which leads to the conclusion that the 85 percent


A11 Buildings with one to three floors B71 Apple fruitA12 Buildings with more than three floors B72 Pear fruitA13 Greenhouses B73 Cherry fruitA21 Non built-up area features B74 Nuts treesA22 Non built-up linear features B75 Other fruit trees and berriesB11 Common wheat B76 OrangesB12 Durum wheat B77 Other citrus fruitB13 Barley B81 Olive grovesB14 Rye B82 VineyardsB15 Oats B83 NurseriesB16 Maize B84 Permanent industrial cropsB17 Rice C11 Broadleaved forestB18 Other cereals C12 Coniferous forestB21 Potatoes C13 Mixed forestB22 Sugar beet C21 Other broadleaved wooded areaB23 Other root crops C22 Other coniferous wooded landB31 Sunflower C23 Other mixed wooded landB32 Rape seeds C30 Poplars, eucalyptusB33 Soya D01 Shrubland with sparse tree coverB34 Cotton D02 Shrubland without tree coverB35 Other fibre and oleaginous crops E01 Permanent grassland with sparse tree/shrub coverB36 Tobacco E02 Permanent grassland without tree/shrub coverB37 Other non-permanent industrial crops F00 Bare landB41 Dry pulses G01 Inland water bodiesB42 Tomatoes G02 Inland running waterB43 Other fresh vegetables G03 Coastal water bodiesB44 Floriculture and ornamental plants G04 WetlandB50 Temporary, artificial pastures G05 Glaciers, permanent snowB60 Fallow land

Table 3: LUCAS land cover nomenclature

U11 AgricultureU12 ForestryU13 FishingU14 Mining and quarryingU21 Energy productionU22 Industry and manufacturingU31 Transport, communication, storage, protective worksU32 Water and waste treatmentU33 ConstructionU34 Commerce, finance, businessU35 Community servicesU36 Recreation, leisure, sportU37 ResidentialU40 Unused

Table 4: LUCAS land use nomenclature


accuracy requirement specified in the Technical Guidelines of CLC2000 has been correctly ful-

filled. Details about LUCAS and the validation approach are described in EEA, 2006a.

APPLICATIONS

The availability of land cover change information has boosted the number of downloads of the

CLC database from the EEA data service (http://dataservice.eea.europa.eu/ last accessed 19 October

2006). The database has been in the top three of the EEA data downloads from the first day of publica-

tion in November 2004. The popularity of the data and the first time availability of land cover change

information have created a market for a wide range of applications. A survey among some 500 projects

from about 6000 registered data users showed that the initial investment cost of roughly 13 Million

Euro has generated revenues in the range of 250 Million Euro through underpinning downstream ap-

plications of the data and services. Application areas range from environment (34 percent), agriculture

(14 percent) and forestry (9 percent) to research and education (22 percent), transport (3 percent), and

physical planning (5 percent).

The EEA itself further developed the method on land accounting (EEA, 2006b; Weber, 2006),

which analyses the stocks and flows (land cover changes) between two given dates (i.e. 1990 and

2000). The method includes an aggregation of individual land cover changes (by class) into groups

of changes (land cover flows) with a similar effect on the territory (e.g. urbanisation, intensification

or extensification of agriculture, deforestation). The method does not only allow looking at new land

cover formations, but also to the sources, i.e. the land that was lost in the process. Figure 2 presents

an illustration from the EEA report on the state and outlook of Europe’s environment (EEA, 2005) on

the increase of artificial lands (land occupied by new constructions) and the land cover classes that are

lost (origin) due to this development.

fUTURE PLANS AND BOTTLENECKS

The availability of land cover change data has triggered a great interest in such information that

the European Commission (EC) has requested the EEA to investigate the possibility for a more fre-


quent update of the CLC database. Recent strategic discussions among member countries, European

Parliament and the main EU institutions responsible for environmental policy, reporting and assess-

ment (DG Environment, EEA, Eurostat and JRC) have underlined an increasing need for factual and

quantitative information on the state of the environment to be based on timely, quality assured data, in

particular in land cover and land use related issues.

EEA and Directorate General (DG) Environment of the EC agreed to explore, within the frame

of the GMES initiative, the best approach for an improved collection of relevant European land cover

and land use data and information. The EEA Management Board endorsed a proposal in June 2005

to update the CLC data together with additional high spatial resolution land cover data as part of the

implementation of the GMES fast track service on land monitoring. DG Agriculture has expressed its

interest to support a CLC update which should be synchronised, as much as possible, with the LUCAS

2006 in-situ monitoring campaign, to provide complementary information on land cover and land use

changes between 2000 and 2006.

Based on the EEA work programme for 2006-2008 to develop activities that integrate spatial

analysis, ex-post policy effectiveness analysis and scenarios tools, to support the understanding of the

Figure 2: Land cover flows: Development of artificial land and its origin.


environmental impacts of sectoral policies and the application of EU funding mechanisms in the 2007-

2013 financial perspective, in March 2006 the EEA put forward a proposal for implementation of the

CLC2006 update. This proposal is based on a collaboration between European Space Agency (ESA)

and the European Commission on the implementation of a GMES Fast Track Service (FTS) on land

monitoring, in line with and backed by the Communication from the Commission to the Council and

the European Parliament “Global Monitoring for Environment and Security (GMES): From Concept

to Reality” (COM(2005) 565 final). The three organisations (EC, EEA, ESA) have agreed to share the

financial investment (approx. eighteen Million Euro) and organisation of this undertaking. While the

EEA and its member countries will be mainly responsible for the national implementation of the CLC

update, the provision of necessary in-situ data and validation of the results, the European Commission

will also support the creation of the land cover change and high-resolution layers while ESA will be

responsible of the provision of the required satellite data.

The proposal builds on the benefits of GMES by combining the planned CLC update with the

production of additional high resolution data for a selected number of land cover classes such as those

concerning built-up areas (degree of soil sealing) and forest. Some of the shortcomings of a standard

CLC update, which is deemed insufficient to meet the wide range of user needs, can be solved by the

creation of complementary high resolution land cover data for a selected number of classes.

The boundary conditions of the CLC update include the following points: The service should

cover all EU member states and neighbouring countries providing a snapshot of a specific year for

which the majority of the satellite data should be acquired;

• Continuity of CLC dataflow should be guaranteed;

• Core land cover data should be available preferably within one and a half years after the

satellite data acquisition in order to ensure timely information;

• Updates with a continental coverage should be envisaged at least every five years; some

environmental or other sensitive areas, i.e. urban areas, mining sites, protected areas, coast-

al zones or other regions with high rate of land use and land cover changes, might require

more frequent updates;


• Coordination of European with national, regional, local monitoring activities should be

fostered, in line with the principle of subsidiarity.

• The GMES service should build on existing land cover and land use experience and moni-

toring activities. Compatibility should be envisaged with CLC (for continental monitor-

ing), Moland (for urban monitoring) as well as the FAO land cover classification system

(for global monitoring);

• Co-ownership of the products should be guaranteed by all actors involved in the service

implementation;

• Open access and free dissemination data policy as applied for IMAGE2000 and CLC2000

based services should be maintained.

Apart from these mainly procedural boundary conditions the implementation of the fast track

service on land monitoring (and with it the update of CLC) is facing several operational hardships.

The failure of Landsat 7 has a significant impact on the availability of suitable satellite image data

for land cover change mapping for the new reference year 2006. SPOT 4 and 5 data cover a much

smaller area, thus requiring more effort on image pre-processing and image acquisition, while data

from the Indian Remote Sensing (IRS) satellites have a good spatial coverage using the Advanced

Wide Field Sensor (AWiFS), but at the expense of spatial resolution.

The cost related to the acquisition of the needed satellite will increase significantly.

Land cover change detection will have to consider multi-sensor approaches with different spectral

and geometric characteristics.

Update on CLC2006 (July 2008)

The CLC2006 project on mapping land cover changes between 2000 and 2006 in 38 European

countries was actually kicked off early 2007. By mid 2008 about 50% of the almost 6 million square

kilometers have been mapped and verified by an independent team. The project will be completed by

mid 2009.


CONCLUSIONS

Comparing the European and North American land cover initiatives, a number of similarities and

differences can be noted. The similarities include the movement from technology driven Earth Obser-

vation solutions to user driven applications or hot topics on how to most effectively detect changes and

the subsequent quality control of the change database. Differences are related to the fact that Europe is

already in possession of a database on land cover changes for a large area (almost four Million square

kilometres) for the year 2000 and that Europe is already affected strongly by the failure of Landsat 7

and the resulting lack of high-quality, low price satellite images.

Similar to North America, the European land cover programme needs to integrate several coun-

tries and languages, but instead of three countries (Mexico, the U.S. and Canada), Europe has (suc-

cessfully) integrated over thirty different nations.

REfERENCES

Bossard, M., Feranec, J., Otahel, J., 2000. CORINE Land Cover Technical Guide – Addendum 2000.

Technical report No 40. Copenhagen (EEA). http://terrestrial.eionet.eu.int

European Commission – JRC, 2002: Building Agro Environmental Indicators – Focussing on the Eu-

ropean area frame survey LUCAS.- Ispra (EUR Report 20521 EN)

European Commission, 2003. Die LUCAS Erhebung – Erfassung von Flächen durch europäische

Statistiker.

European Commission, 2005. GMES - From Concept to Reality” (COM(2005) 565 final)

European Environment Agency, 2002. CORINE Land Cover update, I&CLC2000 project, Technical

Guidelines, http://terrestrial.eionet.eu.int

European Environment Agency, 2005. The European environment - State and outlook 2005. Copen-

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European Environment Agency, 2006a. The thematic accuracy of Corine land cover 2000 - Assess-

ment using LUCAS. Technical report No. 7/2006 (digital report only)

European Environment Agency, 2006b. Land Accounts for Europe, 1990-2000 - Towards integrated


land and ecosystem accounting. EEA Report 11/2006. Copenhagen

Feranec, J., Hazeu, G., Christensen, S., Jaffrain, G. (2007): Corine land cover change detection in Eu-

rope (case studies of the Netherlands and Slovakia). Land Use Policy, 24, 234-247

Heymann, Y., Steenmans, Ch., Croissille, G., Bossard, M., 1994. CORINE Land Cover. Technical

Guide. EUR12585 Luxembourg, Office for Official Publications of the European Communities.

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Documents

CHAPTER 4 EUROPEAN LAND COVER MAPPING – THE …unique land cover and land cover change database has triggered a wealth of downstream applications in the area of environment, agriculture