两湖平原城镇发展的空间过程

２０００多年来，两湖平原城市行政等级体系由两级演变为四级，分别经历了以江陵和武汉为首位城市的两在阶段；城市分布由低级均衡向高级均衡螺旋式上升发展，城市重心由西北向东南迁移；城市空间扩展呈圈层辐合型，丘陵与平原交错带的外缘中心城边缘效应强烈；城市空间结构为雏形的交通－市场最优原则复合型中心地体系。

THE SPATIAL DEVELOPMENT OF THE TWO-LAKE PLAIN''S CITIES FOR THE PAST MORE THAN 2000 YEARS

This paPer researches the urban spatial development on the Two-Lake Plain (in CentralChina)for the past more than 2000 years,and following conclusions are obtained:1.The urban administrative gradation has changed from 2 grade to 4 grade:2 grade during22lBC AD220 and AD589 756;3 grade during AD220 589 and AD757 960;4 grade duringafter AD960.2.The urban development has two historical perids:the period having Jiangling as the chiefcity(before AD1279)and the period having Wuhan as the chief city(after AD1279),and In the13th century,the modern urban spatial structure took its shape basically.3.The urban distributions have 3 times spatial dynamic equilibriums:equilibrium of the distribution of the cities above county level around 200BC,that of cities of county level and above countylevel around AD900,that of all cities and towns around AD1980.4.The centres of gravity of the distributions of cities and towns moved from northwest Qianjiang county to southeast Jianli county,with a straight distance of about 75 kilometers.5.The urban spatial development has a typical circular-convergence model.The shorter thedistance is from the core of the plain,the more the cities which appeared later,almost all citiesabove county level distribute in the periphery of the plain which is the ecotone of hills and plains,showing a powerful ecotone function.6.The urban spatial structure basically accords with Walter Christaller's central-place-theory,having a embryonic compound system of central place stucture which mainly combines the transportation priority with the commerce priority.