Settlement hierarchy

Using size of a settlement can be misleading in some cases as not all population boundaries fit. Some cities (e.g., Norwich, England) have a smaller population than some towns (e.g., Luton, England). In addition, there is no agreement as to the number of levels in the hierarchy or what they should be called. Many terms used to describe settlements (e.g., village) have no legal definition, or may have contradictory legal definitions in different jurisdictions.

Position in an accepted settlement hierarchy can imply status[3] which in turn reinforces the position of the settlement in the hierarchy. Status can derive from being the residence of a King or high-ranking member of the nobility or from being the location of a major religious establishment. A formal hierarchy of settlements, known as a multiple estate appears to have been common in 10th century England.[4] The centre of an estate (often called a "caput") could be supported by subsidiary settlements sometimes given specialised roles. For example, a Saxon royal estate might be supported by settlements specialising in production of cheese or barley or maintaining flocks of sheep.[5]

More than one billion residents.

• Ecumenopolis - a theoretical construction in which the entire area of Earth is taken up by human settlements, or at least, that those are linked so that to create urban areas so big that they can shape an urban continuum through thousands of kilometers which cannot be considered as a megalopolis. As of the year 2009, the United Nations estimated that for the first time more than 50% of the world's populations lived in cities, so if these were linked, the total population of this area would be about 3,400,000,000 people as of 2010.

More than one million residents. At this density, the settlement's population and GDP tends to exceed that of most countries with lesser density. The need for administrative divisions, public transportation, public infrastructure and other government public services is critically essential for the sustainable growth and continued prosperity of its citizens. The first city in recorded history to reach a population of one million residents was Ancient Rome in 133 B.C. During the Second Industrial Revolution, London, England reached the mark in 1810 and New York City, United States made it in 1875.

• Megalopolis or Megacity - a supercity consists of a group of conurbations, containing more than ten million residents in total.
• Conurbation or Global city - an extremely large city consists of a group of metropolises, containing between three and ten million residents.
• Metropolis or Municipality - a very large city with its suburbs consisting of multiple satellite cities and towns. The population is usually between one and three million people.

Less than one million residents. At this density, viable access to advanced services due to economies of scale being abundant.

• Regiopolis or City - a large city with a large population and many services. The population is less than one million but over 300,000 people.
• Prefecture or County - a medium city which has abundant services, but not as many as a large city. The population is between 100,000 and 300,000 people.
• Borough or District- a small city that functions as a type of municipality or subdivision of a consolidated city. The population is usually similar to a large town.

Less than one hundred thousand residents. Common "city features" and services such as clinics, police, fire station, schools, residential neighborhoods, etc. become more prominent. Density is sufficient to support local commercial areas which may include a "Main Street" or a shopping mall.

• Town or Shire - a large town which has a population between 10,000 and 100,000.
• Township or Subdistrict - a medium town which has a population between 1,000 and 10,000.
• Suburb or Locality - a small mixed-use town or residential area, existing either as a part of a city or urban area or as a separate residential community within commuting distance of a city.[7]

Less than one thousand residents. At this number, settlements are too small or scattered to be considered "urban", and services within these settlements (if any) are generally limited to bare essentials: i.e., church, grocery store, post office, etc. Throughout most of human history, very few settlements could support a population greater than 150 people.

• Village or Tribe - a village is a human settlement or community that is larger than a hamlet but smaller than a town. The population of a village varies; the average population can range in the hundreds. Anthropologists regard the number of about 150 specimens for tribes as the maximum for a functioning human group.
• Hamlet or Band - a hamlet has a tiny population (less than 100), with only a few buildings. A social band are the simplest level of foraging societies with generally a maximum size of 30 to 50 people; consisting of a small kin group, no larger than an extended family or clan.
• Homestead or Neighbourhood - a homestead usually consists of a cluster of isolated dwellings normally occupied by a single extended family, normally would only have one to five buildings or elementary families.
• Roadhouse or Bed and breakfast - a roadhouse is a small mixed-use premises typically built on or near a major road in a sparsely populated area or an isolated desert region that services the passing travellers, providing food, drinks, accommodation, fuel and parking spaces to the guests and their vehicles. The premises generally consists of just a single dwelling, permanently occupied by a nuclear family, usually between two and five family members. A roadhouse is often considered to be the smallest type of human settlement.[8]

The position of a settlement in the hierarchy is intended to inform decisions about new developments such as housing. Rather than define the hierarchy by population, an alternative way to construct the hierarchy is based on the services that are available within each settlement. Settlements are described as "level 1", "level 2", etc. rather than using terms such as village or town.[9] The Government planning statement (PPS3) does not specifically mention "settlement hierarchies", but talks about the availability of services to small rural settlements. The term is used a number of times in the guidance for preparing evidence for planning decisions; a settlement hierarchy starts with an isolated dwelling, then hamlet, then village, town, city then a conurbation.

The German planning system is based on the Central Place Theory developed by Walter Christaller in the 1930s and first applied in the Nazi Era, especially in Poland. Every settlement is categorized by function: highly central cities Oberzentrum (e.g. Hamburg, with speciality clinics for tropical diseases), middle central cities Mittelzentrum (for periodic functions e.g. Homburg (Saar) with major schools (starting at 5th grade)) and basic central towns Grundzentrum/Unterzentrum (e.g. Illingen with basic doctors and upermarket). The number of inhabitants is less important: thus a city such as Kaiserslautern (100,000 people) can be a highly specialized city, because it is a centre for the surrounding rural area.

It is used at the federal level for the regional planning system of states and planning regions for the "State Development Programmes" (Landesentwicklungsprogramm [de]) and the "Regional Spatial Structure Plans" (Regionaler Raumordnungsplamn [de]). These are political plans to achieve goals such as equivalent living standards (Gleichwertige Lebensverhältnisse [de]) in rural and urban areas in all of Germany, east and west.