Changes of Built-up Areas of Korean Cities by Urbanization: 1920-1960

Abstract

This study demonstrates the shape changes of the built-up areas of Korean cities along the progress of urbanization. The shape indices of built-up areas were calculated on the 1:50000 topographical maps at the two points of time of 1920's and 1960's with the method which was proposed by Boyce, R. R. and Clark, V. A. V. in 1964. The formula is defined as Shape Index (I)=Σni=1|(ri/Σni=1ri·100-100/n)| where r is the radial distance as measured from the centroid of the built-up area to its edge and n is the number of regularly spaced radii. The Boyce-Clark's shape index has some merits; it can be used for other quantitative analysis, and it is unaffected by the difference scales of maps and its range is 0 to 100. In this study, n is 20.The Q-mode cluster analysis was employed two times with 20 radii and two times with three variables which are population size, size of built-up area and Boyce-Clark's shape index. The author tries to systematize those outcomes to the study which had been analysed with the attributes and interactions of the Korean urban system. Those various approaches make us to interpret urban system in full. As the products of this analysis, the author would like to propose the model of the shape change of the built-up area as Fig. 9 and the conclusions are as follows;1) Urbanization makes the shapes of the built-up areas more simply. So, the shape becomes to a circle steadity. The changes of shapes occur by the growth of urban system along the time serial axis.2) Shape is varied by the interplays to the historical inertias, environments, national economic development level, change of transportation route and technique, agglomeration and diffusion of city functions, regional planning, urban system regulations and interrelating with other systems.3) The dramatic changes of the built-up areas of Korean cites could not be observed in the period of 1920-1960. But in general, it is clear that the shape indices of 1960's decreased than 1920's regardless the growth of built-up area.4) The population density per the built-up area becomes higher. It shows that the agglomeration of the city functions into the CBD, where the intensity of landuse is escalated by that phenomena, so many skyscrapers are constructed and vertical functional differentiations are derived. But at the same time, the tendency that the population density become higher means that the population concentration to the city is faster than the construction of the urban equipments.5) The cluster analysis with three variables produced the greater city groups at the two points of time. The result shows dramatic change. The greater city group is consisted of Incheon, Mogpo, Gunsan, Daegu, Masan in 1920's; but it is consisted of Incheon, Daejeon, Gwangju, Daegu in 1960's. The greater city group of 1960's developed with high speed and become regional central cities to 1980. Since 1960, Korea shows the period of modern urbanization. During the period, the greater city group developed as the base cities of four economic regions of Korea (except Incheon). The development of above cities are perceived as the functional roles become stronger in the Korean urban system. The roles of above cities have been distinguished by the factor analysis with 30 variables and the analysis of the trunk telephone calls along the time serial studies, too.6) The cluster analysis with 20 radii produced the similar outcomes. The greater city group is consisted of Incheon, Daegu in 1960's but the discernable subgroup is consisted of Suweon, Mogpo, Daejeon, Jeonju, Gwangju which are the main Korean greater cities.Above conclusions show that the study of shape is useful for the synthetical urban system analysis.