Towns of Europe: to each country its definition*
Europe's towns bear the stamp of their shared history. Most of them developed around an ancient centre in line with a concentric growth model. However, the definitions used for agglomerations vary from one country to the next. There are two complementary approaches to such definitions. The first focuses on the economic relations between the urban core and its environment and defines the towns' "spheres of influence". The second defines the town in terms of building density: it determines urban areas likely to join up into conurbations. Yet even when using this second method, it is difficult to make international comparisons. In most of the countries (especially in France), the uninterrupted built-up zones around a centre are defined first. The urban area then results from adjusting these zones to the administrative or statistical districts that cover them. The size of the basic districts (generally local administrative areas or inframunicipal gridding patterns) varies considerably from one country to the next (from one in France and to one hundred in Sweden). In other countries, a municipality is called a "town" when it has a certain legal or administrative status (Germany) or when it tops a certain population threshold (Spain, Italy and Portugal). Here, the building fabric is not even taken into consideration. A total of five countries have no definition for the notion of an urban area. In the other countries, disparities between basic gridding patterns and chosen thresholds limit the scope of international comparisons. This is why the French definition, with its low population threshold of 2,000 inhabitants, can appear to be extremely extensive compared with that used in the other countries.