The areas of city influence are contiguous area around a city from where people commute to the city to obtain certain goods or services. A cinema hall may attract patrons from several villages around the city. The contiguous area encompassing all these villages is the area of influence of the city with respect to entertainment through the cinema. Likewise, various institutions in the city such as hospitals, colleges, schools and so on, have their corresponding areas of influence. The areas of influence for different services and goods may cover smaller or larger areas around the city and their shapes may also differ. Thus it is possible to visualise a large number of service areas around a city.
The central places theory explains the different sizes of areas of influence through the maximum reach of services provided by a centre, corresponding to its level in the functional hierarchy of centres.
area of city influence

For a same city, the size of an area of influence may vary from a radius of a few kilometres to radii of several dozens or even hundreds of kilometres, whether influence is measured in function of the extension of the basin of fresh products supply, in function of the pendular moves between home and work (employment basin), in function of the frequency of use that population of surroundings makes of urban retail and services, in function of the recruitment of pupils and students, or in function of the diffusion of regional press. The reach is defined by the maximum extension of the area of influence. Increased transports speed and multiplication of relations in network or at long distance have weakened relevance of the concept of area of influence by reducing the relative importance of proximity relations in contiguity. This concept remains useful to describe the average spatial organisation of flows of population using services, at regional scale.
 Shashikant Nishant Sharma