The Site of a settlement describes the physical nature of where it is located.
Factors such as water supply, building materials, quality of soil, climate, shelter and defence were all considered when settlements were first established.
Aspect relates to the direction in which the land faces.
A supply of water was probably the single most important factor in deciding where a settlement might be located.
A dry point site is one which is slightly raised from the surrounding area.
A wet point site refers to any site which has access to water, usually through being beside a river.
In medieval times, defence was one of the most important factors influencing the site of a settlement.
Anywhere where two routes meet has great potential for settlement.
Many towns and cities have built up at points where it was easiest to cross a large river.
The situation of a settlement is the description of the settlement in relation to the other settlements and physical features around it.
Settlements can be described as being part of the urban hierarchy.
Where they stand on the hierarchy depends on a number of factors, the main ones being population, the number of services a settlement has and its sphere of influence.
The larger the population, the higher the settlement is place on the hierarchy.
The larger a settlement is, and therefore the higher it is one the urban hierarchy, the more services and functions it will have.
The larger a settlement is the greater its sphere of influence is likely to be, as it has a wider range of services and functions to attract people to go there.
There are two major ideas to consider when looking at the sphere of influence of a shop of service.
These are called the range and threshold population of a good.
The function of a settlement describes all the main activities that occur in it.
These can be grouped into a number of headings, such as residential, recreational, retail, government, entertainment and industrial.
Some settlements have one predominant function. Most settlements now are multi-functional, which means that they perform a range of different functions.
Two good examples of the changing functions of a settlement can be seen in Benidorm (Spain) and the South Wales mining towns.
Burgess based his model on the city of Chicago. At its core is the CBD, surrounded by a zone of transition and then the residential areas.
Hoyt used transport routes to determine where his sectors would be located, still centered around a CBD.
Harris and Ullman still have a central CBD, but they also have other smaller centres. Harris & Ullman also have business and industrial parks.
Waugh's model for a developing world city has a central CBD surrounded by high class residences, and beyond them the shanty towns. Industry is found in sector along the main roads.
By drawing a transect of a city, you can quite easily identify the different zones, in much the same way as Burgess and the other theorists did.
The CBD is where shops will locate as they know it is the most accessible point for the people of the city.
Many British cities still have street plans that were laid down hundreds of years ago. The roads cannot cope with the ever increasing numbers of cars and other vehicles.
CBD's are limited in their outwards growth by the fact that the city encompasses them.
The major pollution seen in urban areas is air pollution, or smog.
Some cities have encouraged the growth of out-of-town shopping centres to help traffic, land price and pollution problems.
Solutions to the problems of the CBD include pedestrianisation, park and ride schemes, ring roads, and car sharing.