[DREAL OCCITANIA] Urban Units in Occitania

The concept of urban unity is based on the continuity of the building and the number of inhabitants. An urban unit is a municipality or group of municipalities with a continuous building area (no cut-off of more than 200 metres between two buildings) with at least 2,000 inhabitants. If the urban unit is located in a single municipality, it is referred to as an isolated city. If the urban unit extends over several municipalities, and each of these municipalities concentrates more than half of its population in the continuous built-up area, it is referred to as a multi-communal agglomeration. Municipalities which do not form part of an urban unit are considered to be rural: municipalities with no continuous built-up area of 2,000 inhabitants, and those with less than half of the municipal population in a continuous built-up area. Note: These thresholds, 200 metres for the continuity of the building and 2,000 inhabitants for the population of built-up areas, are the result of recommendations adopted at international level. In France, the distance between two buildings is calculated by analysing the databases on the construction of the National Geographical Institute (IGN). It takes account of cuts in the urban fabric such as rivers in the absence of bridges, graveries, height differences. Since the 2010 demarcation, certain public spaces (cmeteries, stadiums, aerodromes, parking lots, etc.), industrial or commercial land (factories, activity areas, shopping centres, etc.) have been treated as buildings with the 200-metre rule to connect inhabited construction areas, unlike previous divisions where these spaces were only cancelled in the calculation of distances between buildings. Urban units are redefined periodically. The current zoning dated 2010 was established with reference to the population known in the 2007 census and the geography of the territory as of January 1, 2010. A first demarcation of cities and agglomerations was carried out on the occasion of the 1954 census. New urban units were formed in the 1962, 1968, 1975, 1982, 1990 and 1999 censuses.