Ranking of settlement by centrality index and suggest a new method of grading

International Conference on Urban, Regional Planning and Transportation,Paris, France- 2009- Oral

Somaye Garmroudi Dovirani, Mehrshad Khalaj

One of the main problems in spatial and regional development is disconnection and absence of hierarchism relations among settlements. Moreover, assigning and forming the hierarchy of settlement which can be suitable framework for dispensation of population, activities, services and functions in different levels is very important. Thus. using indicators and statistical methods for ranking of settlements in regional spatial system not only can distinguish settlements, but also can help to define the centrality, and all kinds of needful service, also it adjusts the imparity among settlements. Nowadays, developing statistical and computerized methods can help to rank the settlements in geographical studies by different indicators in different themes. Cognition and evaluation of every rural settlement have some difficulties such as:
1 In national scale, we cannot provide enough statistical information like developing potentials of framework plans for every rural settlement;
2 Some of variables like population and services have an internal connection. As a result, estimating of these variables along with each other can change the score of settlement low or up falsely;
3 We cannot quantify some variables easily such as social and cultural features. There are two important main points in order to diagnose of local centrality of settlement:

1 Classification and definition of settlement operations will be performed because in many places there is no possibility of having various functions like universities or general hospitals in rural areas for many reasons. Therefore, we can assume that these main functions can be formed in few places, and other places use them;

2 Evaluation of settlements conditions in every region or zone can be compared with each other. It means that sometime in studied space, one settlement which compared with other settlement can gain first rank and becomes center, but in a larger space of study can gain lower rank.

In this paper we studied centrality indicator method as one of the important methods to define hierarchy of settlements in UFRD approach. This method shows the hierarchic method or ranking the settlement, for defining the ranking settlement, we will discuss the Marshall theory, after that we will explain its negative points, and finally we will propose a new statistical method.

Keywords: Ranking of settlements, centrality index, Marshall Method, Sturges method