Abstract:
Bangkok Metropolis, the capital city of Thailand, has very rapid growth and becomes a primate city which is about fifty times bigger than the secondary one. The flow of population which immigrate to BKM for jobs, educations, and by other pull factors, has caused many problems in BKM. These are, for instances, the problems of congestion, the inadequacy of urban infrastructures, and many social problems. The Government has attempted to eliminate these problems by setting up the decentralization policy to other regions. And in the same time, the authorities which are responsible for urban services and infrastructures are stimulated to alleviate the facing problems and to make the plans for the increased population in the future. The General plan of BKK would be the guide lines of other plans, especially its land use plan should indicate the population distribution and their activities in the future. The difficulties of preparing the land use plan are on the estimation of land requirements and the selection of locations of each land use. The last one is most difficult and often be the weak point of the planners to be attacked in the public hearing that it has been done irrationally and solely by their value judgment. The objective of this study is to apply the new physical planning techniques in the selection and distribution of land uses in Yannawa District. The techniques are Potential Surface Analysis (PSA) and Threshold Analysis. Both are used to demonstrate the scientific approach in planning to eliminate its weak point as mentioned before. The first stage of this study is the application of PSA in the distribution of two major land uses which are residential surface and commercial surface. This study does not take the industrial surface into the consideration because the national policy to stop the polluted industrial development in BKM. The chief principle of this technique is the selection of the physical and socio-economic factors and the weighting of them. These factors are weighted by ten planners and engineers who involve and have experiences in urban planning for years. The average weight of each factor will be used in the calculation of the scores of each cell of the area (which is devided into equal square grid system). The grids which have the highest total scores would have the highest potential for development. The results of this analysis are that the proper location of residential development should be in the area with road network, having the good accessibility to external job and without any physical constraints. And the proper location of commercial area has more or less in the same directions including the factor of continuity from the existing commercial centers. The second stage of the study is to sieve the area proposed for residential and commercial land uses from the institutional land uses by Threshold Analysis Technique. The third stage is to estimate the land requirement in the future for each use and distribute in the areas with highest, high and moderate potential respectively. The final study will propose the land use plan which is synthesized from the three stages mentioned above. The result is showing that the intensity of these two major land uses are along the directions of road networks and distribute in the area without physical constraints for development. Which can be demonstrated obviously by the rational techniques. The limitations of the study is on the factors selected for measuring the values of the areas. Some essential data are not available for the analysis because of the limitation of time and budget for the surveying and gathering them. However, this study should be useful to planning practices learning some scientific approach or mathematic techniques which assist the planners to explain their planning process obviously and rationally.