Location-spatial Analyses for Urban Equipment and Using AHP in the GIS Environment



Extended Abstract

Today, the land use management of urban infrastructure is the main challenge of most of the urban authorities and planners. Urban land use can be review of the two main perspectives. Firstly, the most important concepts that are based on fundamentals thoroughly urban therefore need a way to recognition carefully. Second, that is important tools for achieving the of macro social, economic and physical objectives. This index, the investment of public and private decisions affected on urban growth and quality of physical environment, as well as playing an important role in it.
One of the most important problems in Iranian cities is their vulnerability to natural hazards such as earthquake, storms, etc. This is particularly more critical in old parts of the cities due to the low conditions of their physical fabric considering the quality of materials, less permeability, lack renovation, etc. Iran with its specific geographical position is always exposed to the hazard of earthquake. Fire stations as places for preparation and readiness of emergency personals and trucks are among the major factors for addressing vital services in the cities. They play an important role in providing security and comfort for citizens and developing the economy for cities. It is obvious that giving proper service without delay and burden and without any limitations of urban environment on one, hand and negatively affecting the lives of citizen on the other hand, require the fire stations to be established and located in the proper places and locations.

The method of the present research is based on four stages. In the first stage the literature of the subject was reviewed in the national and international researches to understand the process of urban mal-growth in other regions. Secondly a field work was conducted to collect data, maps and a study on the Master and Detailed plans of the city and zone 6 in Tehran. Thirdly, the different information layers were extracted from various maps (land use, The quality of building, The size of plot, The building age, The level of occupation, The number of floor, Building materials, Density of population and so on) and the satellite images IKONOS 2007 with Arial photos. All the data were corrected geometrically and digitized by applying ARC GIS and CAD. The preparation of these layers was implemented in the context of topology structure, review and geometric correction of images, the Boolean method and weighing and by reaching an appropriate method of integration and recognition. The functions of composite layers were conducted in the framework of union, intersection, clipping, buffering, merge and update. The results of spatial and descriptive of three stages were integrated and weighted by using Boolean Logic and fuzzy logic. Then by analyzing the integrated tables of information data the sites were evaluated. Then the most appropriate land use for fire station is recommended. By using this model, new locations were proposed for establishing fire stations, so that all the area could be completely covered.

Results and Discussion
There are lots of factors that have influence on locating the urban facilities like fire stations. Analyzing all these factors, by using traditional methods of locating such as manual overlapping of the maps, is not possible; because the amount of available data is enormous. In addition, lack of attention to these factors in location the urban facilities will result in wasting a remarkable amount of financial resources and human labor force and energy in the cities and it will impose serious damages on people and governments. Therefore, the appropriate use of data analyzer system like geographical information systems (GIS), which can process a huge bulk of data, is crucial. One of the main capability of GIS as an exclusive system is its potential of integration, modeling and site selecting through land valuation. By integrating and compositing the different criteria the most appropriated location can be selected. There are different methods for criteria composition. Which some of them include as follows: Boolean logic, Index overlay, Probability logic, Coefficient correlation, Artificial Neural Networks, Fuzzy logic or the logic of black and uncertainty, Analytical Hierarchy Process (AHP). AHP is one of the most efficient techniques in decision making. In this model, the first time by Thomas L. Satty was introduced in 1980. The AHP approach is one of the more extensively used MCDM methods. The AHP has been applied to a wide variety of decisions and the human judgment processes.This technique is one of the MCDA methods with many capabilities which are used in different scientific disciplines. The previous researches show that the technique of MCDA which is known AHP is very suitable for solving complicated issues. Obtaining solutions in the AHP is not a statistical procedure, because it can help either a single decision maker or a decision group to solve a MCDM problem .One of the most important advantages of AHP relates to its ability to measure quantitative and qualitative characteristics of a decision. This technique is based on pair comparison and gives the possibility to study different options by the urban managers. Many researches show that AHP technique has proved to be quite useful when is integrated with GIS for site selection. In the present study, there was a try to bring up a new model for locating fire stations in the cities, through integrating hierarchical analyzing model (AHP), and layers evaluation logic and through the use of Geographical Information System (GIS). This model was practiced in the region 6 of Tehran. Fire stations are located at the southern part of this area and the majority of the north and the central parts of this region cannot be covered and properly serviced by these stations. Besides, these fire stations suffer from some weak points like being located in single – direction streets and lack of coverage for all the relative areas.

Results of the model which has been applied on the region fabric illustrate that an AHP approach is a basic tool to identify vulnerability of the region. Its application to the problem helps to unify relevant theory and practice. It also generated maps of vulnerable spots that can be more adaptable to changes and can greatly assist planners and policy makers in decision-making.