New Degree of Urbanisation: Harmonised Definitions of Cities and Rural Areas, Exams of French

Download New Degree of Urbanisation: Harmonised Definitions of Cities and Rural Areas and more Exams French in PDF only on Docsity! Regional and Urban Policy Regional Working Paper 2014 A harmonised definition of cities and rural areas: the new degree of urbanisation Lewis Dijkstra and Hugo Poelman Working Papers A series of short papers on regional research and indicators produced by the Directorate-General for Regional and Urban Policy WP 01/2014 > Executive Summary This paper describes the new degree of urbanisation (DEGURBA) classification. This classification distinguishes three types of areas: densely, intermediate and thinly populated areas. This new approach was developed to harmonise several similar but not identical spatial concepts. The new classification is based on a new source of information: the population grid. This paper shows the benefits of this approach in terms of greater comparability and data availability. It describes the method and how it was developed. The annex contains the original and the new guidance notes on the degree of urbanisation and a section on how to update the degree of urbanisation. It also contains the United Nations (UN) recommendations on localities and urban/rural areas and the definitions of urban areas used in Europe in a recent United Nations Population Division (UNPD) report. Disclaimer: This Working Paper has been written by Lewis Dijkstra and Hugo Poelman, European Commission Directorate-General for Regional and Urban Policy (DG REGIO) and is intended to increase awareness of the technical work being done by the staff of the Directorate-General, as well as by experts working in association with them, and to seek comments and suggestions for further analysis. The views expressed are the authors’ alone and do not necessarily correspond to those of the European Commission. The UNPD only publishes figures using a two-way split in urban and rural. Therefore, the degree of urbanisation needs to be simplified to a two-way split. Urban areas would equal densely populated and intermediate density areas. Rural areas would equal thinly populated areas. The alternative names as defined in the new degree of urbanisation anticipate this two-way split. Intermediate or small urban areas and densely populated or large urban areas are clearly intended to be combined into ‘urban areas’. Despite the variety of definitions used, the population in rural areas in the EU has hovered around 29 % for the past decade. The differences for individual countries, however, are some- times quite substantial. Figure 3: Harmonising with UNPD data UNPD reports Degree of urbanisation Name Alternative name rural areas Thinly populated Rural areas Urban Areas Intermediate density Town and Suburbs Densely populated Cities 2.2.3 Urban Morphological Zones, Urban Clusters and Centres A last spatial concept which could be harmonised is the urban mor- phological zone (UMZ) as used by the European Environmental Agency (2). It is defined as ‘a set of urban areas laying less than 200m apart’. This concept only looks at a number of CORINE (3) land cover classes and does not consider population distribution. Core Classes: • 111 – Continuous urban fabric • 112 – Discontinuous urban fabric • 121 – Industrial or commercial units • 141 – Green urban areas Enlarged core classes: 123 (Port areas), 124 (Airports) and 142 (Sport and leisure facilities), are also included in the UMZ if they are neighbours to the core classes or if they are next to another enlarged core class which is a neighbour to the core classes. 122 (Road and rail networks) and 511 (Water courses), when neighbours to the enlarged core classes, cut by 300m buffer. Forests and scrub (311, 312, 313, 322, 323, 324), when they are completely within the core classes. The UMZs are constructed using a higher resolution (100 m x 100 m) data as compared to the 1 km2 grid. However, the presence of strip This method identified the vast majority of cities, but it also included LAU2s which were more suburban than urban or included several smaller towns but no single centre of at least 50 000 inhabitants. The Urban Audit covered a large sample of cities with at least 50 000 inhabitants. These cities were not selected in a harmonised manner. The Urban Audit was not identical to the densely popu- lated areas identified by the original degree of urbanisation. Figure 1: Four conflicting spatial concepts Urban-Rural Typology Degree of urbanisation Urban Audit Rural LAU2 Thinly populated Intermediate density Densely populated Cities In 2010, the European Commission published a new definition of urban and rural regions, which was similar in approach to the OECD method but relied on population grids instead of LAU2s (for more information see Eurostat Regional Yearbook 2010). This definition introduced the concept of rural grid cells. They are used to define rural regions and rural LAU2s. This ensures that rural areas and rural regions are defined based on the same concept (rural grid cells). It also meant that rural areas and thinly populated areas were now identical (1). The new degree of urbanisation uses urban centres to identify all cities with a centre with at least 50 000 inhabitants. All these cities were subsequently included in the Urban Audit and Urban Audit cities without a centre of this size were dropped. As a result, densely populated areas are now identical to the cities used in the Urban Audit data collections. Figure 2: Harmonised spatial concepts Revised degree of urbanisation Thinly populated = Rural LAU2 Intermediate density Densely populated = Cities 2.2.2 UNPD publications on urban and rural areas The new degree of urbanisation can also be used to supply data to the UN on urban and rural areas. In this case, the degree of urbanisation does not replace another EU-wide definition, but a myriad of different national definitions. For an example of the variety of definitions of urban areas used in UNPD reports see annex 5. 1 For more information on the link between the degree of urbanisation and the urban-rural regional typology follow this link: http://epp.eurostat.ec.europa.eu/ statistics_explained/index.php/Territorial_typologies 2 http://www.eea.europa.eu/data-and-maps/data/urban-morphological-zones-2006-umz2006-f3v0 3 CORINE stands for 'coordination of information on the environment' see http://www.eea.europa.eu/publications/COR0-landcover A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 3 Map 1: New degree of urbanisation “- ae Degree of urbanisation Classification of LAU2 units Hl Densely populated areas (cities) @ Intermediate density areas (towns and suburbs) Hl thinly populated areas (rural areas) No Data Sources: DG REGIO, Eurostat 0 SO0OKm uroGeograchics Astonation forthe admevatrative boundaries 3 WHAT IS THE NEW DEFINITION? (SHORT VERSION) The new degree of urbanisation creates a three-way classification of LAU2s as follows: 1 Densely populated area: (alternative name: cities) • At least 50 % living in high-density clusters (4) (alternative name: urban centre). 2 Intermediate density area (alternative name: towns and suburbs) • Less than 50 % of the population living in rural grid cells; and • Less than 50 % living in a high-density cluster. 3 Thinly populated area (alternative name: rural area) • More than 50 % of the population living in rural grid cells. or linear development along certain roads leads to UMZs with the shape of a spider web linking separate urban centres with very few economic links. Although the UMZ concept is clear to experts, the general public may be confused by the references to urban areas and urban functions. The UMZ method does not check for population den- sities or population size as the other urban area definitions do. Although the UMZ talks of urban areas, it primarily refers to 'built-up areas'. Also the references to urban functions should not be interpreted as referring to a functional urban area or a functional economic area. The UMZ method does not analyse functional economic links or commuting flows. As the UMZs are not used to collected data, but only to aggregate existing information, replacing the UMZs with urban centres does not increase data availability. The main benefit of using urban centres instead of UMZs would be the closer link with data col- lected following the degree of urbanisation. Map 2: Urban morphological zones, Urban clusters and Urban centres 4 To ensure that the population of each high-density cluster is appropriately represented (min. 75 %) by densely populated LAU2s, 25 LAU2s were added to this category. This also ensures that 20 high-density clusters are included, which otherwise would be dropped. A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 5 Map 3: Step in the creation of Urban Centres (the case of Paris) Therefore, the classification for these regions has been done based on other sources (LandScan (9) data) which DG for Regional and Urban Policy has acquired. 5.2 Rural grid cells and urban clusters A rural LAU2 has 50 % of its population living in rural grid cells. • Rural grid cells: Grid cells outside urban clusters. • Urban clusters: Clusters of contiguous (10) grid cells of 1 km2 with a density of at least 300 inhabitants per km2 and a minimum population of 5 000. The calculation is done in two steps: First, all cells with a population density of 300 inhabitants per km2 are selected. Secondly contiguous cells are plotted (see fig- ure below): Contiguous groups 400 550 2100 G1 G2 G2 500 400 G1 G2 1500 350 G1 G1 2000 1250 G1 G1 The groups of contiguous cells with a density above the thresh- old with a total population of 5 000 or more are selected. These are urban clusters. Population in group Urban Cluster Population 3050 Population 6000 The resulting raster of urban clusters is available here: https://circabc.europa.eu/sd/a/a932d937-82fe-48b6-9c14- 1d549ac494f3/URB_CLST_2006.zip The urban clusters can be overlaid on LAU2s, which allows us to calculate the share of population of each LAU2 living in an urban cluster. If less than 50 % live in an urban cluster, the LAU2 is clas- sified as rural. 5.3 High-density clusters (city centres) To make a distinction between densely (large urban) and inter- mediate (small urban) we classify as densely those LAU2s where 50 % or more of the population lives in a high-density cluster. • High-density cluster: Contiguous (11) grid cells of 1 km2 with a density of at least 1 500 in- habitants per km2 and a minimum population of 50 000. The raster of high-density clusters is available here: https://circabc.europa.eu/sd/a/d4ded292-c66b-4927-ae8e- 2c6f2b606b46/HDENS_CLST_2006.zip The method to identify high-density clusters is similar to the method of the urban clusters. First, all cells with a population density of more than 1 500 inhabitants per km2 are selected. Secondly, contiguous high-density cells are grouped. In contrast 9 http://www.ornl.gov/sci/landscan 10 Contiguity includes the diagonal. 11 Contiguity does not include the diagonal (i.e. cells with only the corners touching) and gaps in the cluster are filled (i.e. cells surrounded by a majority of high-density cells applied iteratively). 8 to the urban clusters, diagonal contiguity is not included. The last steps fill gaps and smooth sharp borders (see figure below). This is done by applying the majority rule iteratively. This means that if five or more of the cells surrounding a cell belong to a single high-density cluster, it is added to that high- density cluster. This is repeated until no more cells are added. The high-density clusters can be overlaid with LAU2s, which allows us to calculate the share of the population of each LAU2 living in a high-density cluster. If more than 50 % live in a high- density cluster, the LAU2 is classified as densely populated. As a last step, a number of LAU2s are included in the densely populated class to ensure that all high-density clusters have at least 75 % of their population in this class. 5.4 Three contiguity rules This section illustrates the three contiguity rules mentioned above: 1 Contiguous including diagonals (urban clusters) If the central square in Figure 1 is above the density thresh- old, it will be grouped with each of the other surrounding eight cells that exceed the density threshold. 2 Contiguous excluding diagonals (high-density clusters) If the central square in Figure 1 is above the density thresh- old, it will be grouped with each of the four cells directly above, below or next to the central square that exceed the density threshold. This means that cell numbers 2, 4, 5 and 7 can be included. Cell numbers 1, 3, 6 and 8 cannot as they have a diagonal connection. 3 The majority rule (gap filling in high-density clusters) The goal for the high-density clusters was to identify urban centres without any gaps. Therefore enclaves needed to be filled. If the central square in Figure 1 is not part of a high- density cluster, it will be added to a high-density cluster if five or more of the eight surrounding cells belong to a single high-density cluster. This rule is applied iteratively until no more cells can be added. 5.5 Completing and correcting the classifications To classify LAU2s based on a population grid, the LAU2s have to be transformed into a raster as well, which can lead to some situations which require an ad-hoc solution. Contiguous grid cells 1 2 3 4 5 6 7 8 5.5.1 LAU2 without a raster equivalent Some small LAU2s do not have a raster equivalent. These have been classified according to the share of area in rural grid cells and high-density clusters. 5.5.2 Border effects Thinly populated LAU2s classified as intermediate density or densely populated may be classified incorrectly if rural grid cells cover most of the territory. The LAU2s with a population below 5 000 inhabitants and with 90 % or more of its area in rural grid cells were reclassified as thinly populated. Small LAU2s classified as ‘rural areas’ may be classified incor- rectly due to the coarse resolution of the population grid com- pared to the small size of the LAU2s. LAU2s with an area less than 5 km² but with a share of surface outside rural grid cells higher than 30 % were reclassified as intermediate density or densely populated according to the share of the corresponding cluster. 5.5.3 LAU2 with no population in the raster equivalent A few LAU2s do not have a population in their raster equivalent, although according to the census they do have a density higher than 150 inh./km². These have been classified according to the surrounding LAU2s and the census data. 5.5.4 LAU2s outside the current population grid The CORINE land cover map does not cover the four French overseas regions, the Azores and Madeira of Portugal. DG Regional and Urban Policy has acquired the LandScan popula- tion grid for these regions and used that grid to classify the LAU2s of these regions. 5.6 Adjusting the cities The definition of the degree of urbanisation specifies that: As LAU2s vary considerably in area, this methodology will lead to a closer match between a high-density cluster and densely populated LAU2s in countries with small LAU2s than in those with large LAU2s. To take this difference into account, the clas- sification can be adjusted as following: • A densely populated LAU2 can be classified intermediate as long as 75 % of its high-density cluster population remains in densely populated LAU2s. • A thinly populated or intermediate density LAU2 can be classi- fied as densely populated if it belongs to a group of LAU2s with a political function and if the majority of the population of this group of LAU2s lives in a high-density cluster. A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 9 An example of the application of the first rule is Vienna. An example of the second rule is Toulouse. These modifications were made based on requests from the national statistical institutes and verified by the European Commission. 5.7 Other adjustments This method can be distorted by two elements: the type of grid used; and the geography of the area. In countries where no bottom-up grid was available, the method may be less accurate due to the resolution of the data (mainly CORINE land cover and LAU2 population) used in the population disaggregation grid. More information about the disaggregation method can be found at: http://www.eea.europa.eu/data-and-maps/ data/population-density-disaggregated-with-corine-land- cover-2000-2. Future updates will increasingly rely on bottom-up grids and disaggregation using high resolution data. The method does not take into account the presence of steep slopes. As a result, the method may not identify high-density clusters or urban clusters in these types of areas. Due to these two sources of possible distortion, national statis- tical institutes were asked to verify and validate the classifica- tion. NSIs could propose additional cities with an urban centre with at least 50 000 inhabitants. These were verified by the Commission to ensure that they indeed had such an urban cen- tre, for example by examining the population size of the high- density clusters below 50 000 within the city boundaries or analysing the data produced using a more precise national pop- ulation grid. For example, the city of Trondheim did not have a centre of 50 000 inhabitants according to this methodology, but this is likely to be due to the geography of the city. In some cases, NSIs have asked to exclude a city. Some of the reasons to exclude a city were that it lacked functions of a centre, it had a negative commuter balance or the population of its urban centre was likely to be below 50 000 (today). These requests were verified by the Commission and if the estimated population of the urban centre was close to the threshold and/or the other reasons were valid, the city was excluded. NSIs could also request minor corrections to the thinly popu- lated and intermediate categories. Map 4: High density cells, urban centre and city (Wien) Map 5: High density cell, urban centre and city (Toulouse) 10 Map 7 A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 13 The new degree of urbanisation also uses the same building blocks as the urban-rural regional typology. As a result, the data collected for rural areas is linked to the data collected for rural regions as they are both defined by the share of population in rural grid cells. Last but not least, this new degree of urbanisation could also be used to provide the UN with annual data for urban and rural areas. Until now, annual data for these type of areas was diffi- cult to find and was based on a wide diversity of urban-rural classifications which undermined the comparability of the data. 7 CONCLUSION The new degree of urbanisation takes advantage of a new tool, the population grid, to create a more accurate classification. It takes account of the population distribution within and between local administrative units level 2. In addition, the switch to the new classification allows a further harmonisation of spatial concepts by ensuring that the cities and densely populated areas are identical and as well as thinly populated areas and rural areas. Map 8 Type of clusters 14 Map 10 Old degree of urbanisation Map 9 New degree of urbanisation A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 15 • Thinly populated LAU2s may be classified as intermediate or densely populated due to border effects if rural grid cells cover most of the territory. For that reason, LAU2s with a population below 5 000 inhabitants (15) and 90 % of its area in rural grid cells are reclassified as rural areas. • Very small densely populated LAU2s may be classified as thinly populated due to the coarse (16) resolution of the population grid. For that reason, LAU2s with an area of less than 5 km² but with a share of surface outside rural grid cells higher than 30 % are reclassified as intermediate density or densely populated according to the share of the correspondent cluster. As LAU2s vary considerably in area, this methodology will lead to a closer match between a high-density cluster and densely populated LAU2s in countries with small LAU2s than in those with large LAU2s. To take this difference into account, the clas- sification can be adjusted as follows: • A densely populated LAU2 can be classified as intermediate as long as 75 % of its high-density cluster population remains in densely populated LAU2s. • An thinly populated or intermediate density LAU2 can be classi- fied as densely populated if it belongs to a group of LAU2s with a political function and if the majority of the population of this group of LAU2s lives in a high-density cluster. A LAU2 consists of municipalities or equivalent units in the 28 EU Member States and EFTA countries and corresponds to the following entities: Belgium Gemeenten/Communes Bulgaria Naseleni mesta Czech Republic Obce Denmark Kommuner Germany Gemeinden Estonia Vald, Linn Greece Demotiko diamerisma/Koinotiko diamerisma Spain Municipios France Communes Ireland DEDs/Wards Croatia Cyprus Dimoi, koinotites Latvia Pilsētas, novadi, pagasti Lithuania Seniūnijos Luxembourg Communes Hungary Települések Malta Kunsilli Netherlands Gemeenten Austria Gemeinden Poland Gminy Portugal Freguesias Romania Communes, Municipiu, Orajse Slovenia Občine Slovakia Obce Finland Kunnat/Kommuner Sweden Kommuner United Kingdom Wards (or parts thereof) Turkey Köy Iceland Sveitarfélag Norway Kommuner Switzerland Gemeinden/Communes/Comuni Note: This new methodology of classifying urban and rural areas has been agreed by DG Regional Policy, DG Agriculture and Rural Development and Eurostat. It replaces the methodol- ogy used in the LFS so far. The older methodology can be con- sulted in previous versions of the explanatory notes. The definition of urban clusters is drawn from the new method- ology to classify urban and rural regions developed and agreed by DG Regional Policy, DG Agriculture and Rural Development, Eurostat and the JRC in 2010. The definition of high-density clusters is drawn from work done in 2011 by the OECD and DG Regional Policy on a new metropolitan area definition. 3 HOW TO UPDATE THE NEW DEGREE OF URBANISATION The new degree of urbanisation (DEGURBA) has been applied to the local administrative units (17) (LAU) as of 1 January 2011. It will have to be updated to take into account the possible changes in the LAU boundaries. This can be done by reapplying the full methodology or by applying a simpler approach which does not rely on using geographical information systems. This simpler approach is particularly suitable for relatively minor changes in the LAU boundaries. This section describes this sim- pler method to update the DEGURBA. LAU boundaries change in three different ways: mergers, boundary shifts and splitting. The most common change to LAUs in the last decade is merging, boundary shifts are less common and splitting is least common. Therefore, this section starts with a detailed description of how to deal with mergers. The second part focuses on boundary shifts. The last part pro- vides a simple approach to splitting. 16 ‘Coarse’ in relation to the small area of these particular LAUS2s. 17 In most cases, LAU level 2 was classified. In some cases, where the LAU2s are small and little to no data is available at that level, level 1 was classified instead. In a few cases, the matching with the political functions of the densely populated areas meant that LAU1s were used for densely populated areas, while LAU2s were used for thinly populated and intermediate areas. 18 3.1 Merging LAU 3.1.1 Merging LAUs with the same degree of urbanisation The new degree of urbanisation is additive, meaning that if two LAUs are classified as low density, classifying both LAUs together will also make them low density (idem for the two other degrees). If two or more LAU2s of the same degree of urbanisation merge, the new merged LAU should remain in the same degree. 3.1.2 Merging LAUs with different degrees of urbanisation The new degree of urbanisation treats the densely populated areas or cities in a specific manner, which means that merges between a thinly populated or intermediate density area and a densely pop- ulated area have to be addressed in a particular manner. 3.1.3 Merges with a densely populated area The new DEGURBA specifies that each high-density cluster should have at least 75 % of its population covered by a densely populated LAU2. This implies that a densely populated area can (in relatively rare cases) have less than 50 % of its population inside a high-density cluster. Therefore, even if a merge leads to a drop of the share of population in a high-density cluster to below 50 %, the new LAU will most likely have to be densely pop- ulated to ensure that at least 75 % of the population of the high- density cluster remains included in a densely populated area. The new DEGURBA foresees a method to match the densely populated area with a geographic area which has administra- tive functions. As the merging of the LAU will lead to the admin- istrative function covering both the old and the new LAU, this link should be maintained in the new LAU. The new DEGURBA is also linked to a city data collection (the Urban Audit). Therefore, all changes in the densely populated area should be mirrored in the Urban Audit. Therefore, these changes should be made in consultation with the national Urban Audit coordinators. These elements mean that: All merges with a densely populated area should be classi- fied as densely populated (18). 3.1.4 Merges between thinly populated areas and intermediate density areas These merges can be addressed in two simple ways: using the pop- ulation in an urban cluster; and using the population of the LAUs. 1. If the population in the relevant urban cluster(s) is available in the list published by the Commission (19) and the population in the relevant LAUs has not changed significantly since 2006, adding the population in an urban cluster for each of the LAUs and dividing it by the total population of the new LAU will deter- mine the DEGURBA. If more than 50 % of the population of the new LAU lives in an urban cluster, the new LAU should be intermediate density. If the population share is less than 50 %, the new LAU should be thinly populated. 2. If the population in an urban cluster cannot be identified based on the list published by the Commission (due to previous changes) or if the population in these LAUs has changed signifi- cantly since 2006, the DEGURBA of the new LAU can be deter- mined based on the population distribution between the LAUs. If more than 50 % of the population of the new LAU comes from thinly populated LAUs, the new LAU should be thinly populated. If more than 50 % of the population of the new LAU comes from intermediate density LAUs, the new LAU should be inter- mediate density. 3.2 Boundary shifts Whereas merges can be dealt with perfectly by using a simple method, boundary shifts cannot always be as reliably addressed. In some rare cases, boundary shifts even between LAUs in the same degree of urbanisation can lead to a change in classifica- tion (20). Due to this complexity, a simple rule of thumb may be the most efficient approach. If a LAU loses less than 25 % of its population or gains less 50 % of its population due to boundary shifts, the degree of urbanisation does not change. This rule of thumb will probably cover 90 % of all boundary shifts and ensures a maximum continuity in degree of urbanisation. 18 In exceptional cases, where the high-density cluster is close to the 50 000 population threshold and the merge leads to a very low population share living in the high-density cluster, the new LAU can be classified as thinly populated or intermediate (depending on the size of the urban cluster) if this LAU is simultaneously dropped from the Urban Audit. 19 For each LAU2, an estimate of the 2006 population inside an urban cluster and the total population is published on the RAMON website (Eurostat’s metadata server). The 2006 figures should be used to keep consistency between the total population and the urban cluster population. The Commission will publish 2011 figures for the two types of clusters and the LAU when they are available. In most cases, using 2006 data instead of more recent data will make no difference in the classification. 20 For example, two thinly populated areas have a number of small and medium-sized towns which contain in each case about 45 % of their population. A number of these towns are shifted to the other area, tipping the population in urban clusters over 50 %. This would lead to a thinly populated LAU2 becoming intermediate. A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 19 If this occurs, it cannot be assessed purely on population shares of the original LAU. Two simple methods can be used in these situations: 1 Look at the map with the urban clusters and high-density clusters and the LAU boundaries to determine whether the shift in boundary is likely to change the population share per cluster in the revised LAU. 2 Look at a local map to determine whether the boundary shifts primarily affect rural areas, suburban or urban areas. 3.3 Splitting LAU This type of change is relatively rare. Therefore, the main rec- ommendation is one of continuity, i.e. give the same degree of urbanisation to all the new LAUs. If a LAU is split, the new LAUs should get the same degree of urbanisation as the old LAU. If there are concerns that the new LAUs may have different urban structures, the same approaches described for boundary shifts can be used: 1 Check the population share per grid cell for the old LAU. For example, if the old LAU has 100 % of its population in rural grid cells, splitting will have no impact. 2 Check the pattern of urban clusters and high-density clusters on the map. 3 Check the urban structure on a local map. 3.4 Conclusion This section provides an overview of how to identify the degree of urbanisation of LAUs that have changed since 2011 without using geographic information systems (GIS). The Commission will update the degree of urbanisation when a complete 2011 population grid becomes available and apply it to the most recent LAU boundary set available. If this is not the case, a further investigation may be required. Three cases are described below. 3.2.1 Changes in DEGURBA can be excluded For each LAU, the share of population in three types of grids cells is known. This share allows us to identify situations where the DEGURBA cannot be changed. For example, if a LAU that has 100 % of its population in rural grid cells shrinks, it will always remain thinly populated. If that LAU adds population, it would have to more than double its population (with population living exclusively in an urban clus- ter) before it would become intermediate. If a boundary shift leads to a change in population that is too small to tip the population share of the revised LAU below 50 % of the relevant grid cells, it keeps the same degree of urbanisation. 3.2.2 Changes in DEGURBA are unlikely but cannot be excluded If the boundary shifts lead to a change in population that is theoretically sufficient to tip the share of population below or above 50 %, but the shift is between LAUs with the same degree of urbanisation, than the same degree of urbanisation should be kept. 3.2.3 Changes in DEGURBA are likely In some cases, changes in DEGURBA are likely. Take for exam- ple, if a city annexes a suburb located in a neighbouring LAU. The city (densely populated area) gains a small share of popu- lation (DEGURBA unchanged). The intermediate area loses 30 % of its population and that population it lost was located in an urban cluster (suburb). The population in the revised LAU now has less than 50 % of its population living in an urban cluster and thus becomes thinly populated. Merging LAUs Merging the same degree of urbanisation Merging densely populated areas with other areas Merging thinly populated and intermediate areas 1 merged with 1 = 1 2 merged with 2 = 2 3 merged with 3 = 3 1 merged with 2 = 1 1 merged with 3 = 1 2 merged with 3 = 2 or 3 depending on population share in urban clusters or in original LAUs Boundary shifts Rule of thumb: If a LAU loses less than 25 % of its population or gains less 50 % of its population due to boundary shifts, the degree of urbanisation does not change Changes excluded Changes unlikely Changes likely Change in population too small to change degree of urbanisation Change in population is bigger but unlikely to change degree of urbanisation Boundary shifts target a specific type of grid cells or urban structure Splitting LAUs Splitting 1 = 1 and 1 Splitting 2 = 2 and 2 Splitting 3 = 3 and 3 3.5 Summary table 20 5 DEFINITIONS USED OF URBAN AREAS IN UNPD WORLD URBANIZATION PROSPECTS (2009) UN Methodology to identify urban population Country Sources Definition Belgium Census of 1981; Estimate for 1976; UN Estimates for 1961, 2000 and 2006. Cities, urban agglomerations and urban communes following the 1977 administrative reclassification (2000 and 2006 UN estimates are based on communes with 5 000 inhabitants or more). Bulgaria Censuses of 1956, 1965, 1975, 1985, 1992 and 2001; Estimates for 1960, 1970, 1980 and 2003. Towns, that is, localities legally established as urban. Czech Republic Censuses of 1950, 1961, 1970, 1980, 1991 and 2001. Municipalities with 2 000 inhabitants or more. Denmark Censuses of 1950, 1955, 1960, 1965 and 1970; Estimates for 1990, 2000, 2001, 2003 and 2004; Registers of 1976, 1981 and 2006. Localities with 200 inhabitants or more. Germany Censuses of 1950, 1961 and 1987; Estimates for 1970, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004 and 2005. Communes (kreisfreie Städte and Kreise) with population density equal or greater than 150 inhabitants per km2. Estonia Censuses of 1959, 1970, 1979, 1989 and 2000; Estimates for 1994 and 2007. Population of officially designated urban settlements including cities, cities without municipal status and towns. Ireland Censuses of 1951, 1956, 1961, 1966, 1971, 1981, 1986, 1991, 1996, 2002 and 2006. Persons living in population clusters of 1 500 or more inhabitants (aggregate town areas, including suburbs). Greece Censuses of 1951, 1961, 1971, 1981, 1991 and 2001. Municipalities and communes in the largest population centre with 10 000 inhabitants or more, plus 18 urban agglomerations as defined in the 1991 census: Greater Athens (Athínai), Thessaloniki, Pátrai, Iraklion, Vólos, Chania, Irannina, Chalkida, Agrino, Kalamata, Katerini, Kerkyra, Salamina, Chios, Egio, Rethymno, Ermoúpolis and Spárti. Spain Censuses of 1950, 1960, 1970, 1981, 1991 and 2001. Municipalities (municipios) with 10 000 inhabitants or more. France Censuses of 1954, 1962, 1968, 1975, 1982, 1990 and 1999. Communes with 2 000 inhabitants or more living in houses separated by at most 200 meters; or communes in which the majority of the population is part of a multi-communal agglomeration as defined above. French Guiana Censuses of 1954, 1961, 1967, 1982, 1990 and 1999. Not available. Réunion Censuses of 1954, 1967, 1974, 1982, 1990 and 1999. Communes with 2 000 inhabitants or more living in houses separated by at most 200 metres; or communes in which the majority of the population is part of a multi-communal agglomeration. Martinique Censuses of 1954, 1961, 1982, 1999 and 2006; Estimate for 1967. For the census in 1990 and 1999, total population of the Commune of Fort-de-France plus the agglomerations of other communes with 2 000 inhabitants or more. Guadeloupe UN Estimates for 1954, 1961, 1967, 1974, 1982, 1990 and 1999. Localities with 2 000 inhabitants or more. Italy Censuses of 1951, 1961, 1971, 1981, 1991 and 2001. Communes with 10 000 inhabitants or more. Cyprus Censuses of 1956, 1960, 1973, 1982, 1992 and 2001. Six district towns and the suburbs of Nicosia and Larnaka. Latvia Censuses of 1959, 1970, 1979, 1989 and 2000; Estimates for 1981, 1986, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2001, 2002, 2003, 2004, 2005 and 2006. Cities and urban-type localities, officially designated as such, usually according to criteria based on the number of inhabitants and predominance of non- agricultural workers and their families. A HARMONISED DEF IN IT ION OF C IT IES AND RURAL AREAS : THE NEW DEGREE OF URBANISAT ION 23 Country Sources Definition Lithuania Censuses of 1959, 1970, 1979, 1989 and 2001; Estimates for 1950, 2005 and 2007. Cities and urban-type localities, officially designated as such, according to criteria based on the number of inhabitants and the predominance of non- agricultural workers and their families. Luxembourg Censuses of 1961, 1971, 1981 and 1991; Estimates for 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000 and 2003. Communes with 2 000 inhabitants or more. Hungary Censuses of 1960, 1970, 1980, 1990 and 2001; Estimate for 2005. Budapest and all legally designated towns. Malta Censuses of 1957, 1967, 1985, 1995 and 2005. No official definition available. In the present publication, localities with 2 500 inhabitants or more. Netherlands UN Estimates for 1950, 1960, 1970, 1980, 1990 and 2000. Due to several historical changes in definition of urban areas, urban is defined in this publication as municipalities with 20 000 inhabitants or more. Austria Censuses of 1951, 1961, 1971, 1981, 1991 and 2001; Estimates for 2005 and 2007. Based on the concept of a functional and structural urban area (Stadtregion) consisting of an urban core area (Kernzone) and surrounding urban areas. (Außenzone). The surrounding urban areas is defined as an area in which at least 30 % of working adults commute daily into the corresponding core area. Poland Censuses of 1950, 1960, 1970, 1978, 1988 and 2002; Estimate for 2005. Towns and settlements of urban nature (for example, workers' settlements, fishermen's settlements and health resorts). Portugal Censuses of 1950, 1960, 1981, 1991 and 2001. Agglomerations of 2 000 inhabitants or more. Romania Censuses of 1956, 1966, 1977 and 1992; Estimates for 2002 and 2003. Municipalities and towns with certain urban socio- economic characteristics. Slovenia Censuses of 1953, 1961, 1971, 1981, 1991 and 2002; Estimate for 2006. Settlements with over 3 000 inhabitants; settlements with 2 000-3 000 inhabitants and a surplus of workplaces; settlements that are seats of municipalities and have at least 1 400 inhabitants and a surplus of workplaces; suburban settlements that have fewer inhabitants but are spatially and functionally integrated with the city. Slovakia Censuses of 1950, 1961, 1970, 1980, 1991 and 2001. Cities with 5 000 inhabitants or more. Finland Censuses of 1950, 1960, 1970, 1975, 1980, 1985, 1990 and 2000; Estimate for 2004. Urban communes. Sweden Censuses of 1950, 1960, 1965, 1970, 1975, 1980, 1985 and 1990; Estimates for 1995 and 2000; Register of 2005. Built-up areas with at least 200 inhabitants and where houses are at most 200 metres separated from each other (according to the administrative divisions of 2003). United Kingdom Censuses of 1951, 1961 and 1971; Estimates for 1981, 1991 and 2001. England and Wales: urban areas formed of continuously built-up urban land, the largest urban areas forming agglomerations in which urban subdivisions are recognised. Scotland: urban localities, similar in concept to urban areas in England and Wales, except that the urban localities as defined do not extend across local government district boundaries. Northern Ireland: urban area formed of continuously built up land, forming an agglomeration in which urban subdivisions are recognised. Prior to 1974 (England and Wales) and 1975 (Scotland) the definition of urban and rural was based on administrative boundaries. The census figures refer to the population present. In order to achieve consistency in the definition of an urban area it was assumed for the 2001 census that an urban area in England and Wales had a population of at least 1 500 people; in Northern Ireland it was 1 000 people or more; while in Scotland is was assumed that all settlements and localities were assumed to be urban. 24