作为区域中心城市(省会),南昌体现出居中性(离几何中心、人口中心、经济中心相对较近)的明显区位特征;作为流域中心城市,南昌位于赣江流域最大的支流抚河与干流的交汇处,这同样符合流域中心城市产生的一般规律;作为赣江三角洲的顶水点,南昌获得了更大的发展空间。这一区位特性却为一般流域中心城市所缺失。这样,居中性、干支流交汇处、三角洲顶水点的综合区位优势,奠定了南昌在赣江流域当之无愧的中心城市地位。本文所揭示出的三角洲顶水点城市的概念,对流域空间结构的综合分析,具有重要的理论意义和应用价值。

As a regional central city, the position of Nanchang in Jiangxi province reflects some typical central location characteristics. And as a central city in a river basin, Nanchang stands at the conjunction of Ganjiang River and Fuhe River which is the largest branch of Ganjiang River in Ganjiang River Basin, which accords with the discipline of forming central city in river basin. Moreover, as an apex city in Ganjiang River Delta, Nanchang occupies larger space than others which is in favor of regional economic development. Obviously, it is hard to see that other common center cities in river basin can get those location characteristics. All comprehensive location advantages of central location, conjunction of rivers and apex in delta together make Nanchang fully deserve the principal center city status in Ganjiang River Basin. Generally speaking, the location advantages of central city in river basin are determined by two factors, one is the trend of pointing to center as a central city, which drives a central city sit on the center in the river basin. Of course, it is not necessarily the geometric center, but more likely to be the population center or economic center; the other one is the trend of pointing to the conjunction of main stream and branch. If the centrality indicates that central city must be sit on the center in river basin, and then, the micro-location of central city is determined by the conjunction of main stream and branch. In sum, the location characteristics of Nanchang completely meet the general location features of the valley central city. On the other hand, the particularities of Ganjiang River Basin make Nanchang possess a special location feature which other valley central cities do not, that is being on the apex of the Ganjiang River Delta. Generally speaking, the location direction of pointing to conjunction impossibly tally closely with the location direction of pointing to apex of river basin. The location feature of Nanchang makes Nanchang get the outstanding location advantage for developing itself even though it does not sit on the conjunction of main stream and branch since Fuhe River moves eastward.