Regional structure and spatial morphology characteristics of oasis urban agglomeration in arid area —A case of urban agglomeration in northern slope of Tianshan Mountains, Northwest China

It is great important to the health development of urban agglomeration to correctly understand the formation and development law of regional structure of urban agglomeration. Employing the analysis methods like fractal theory and quantitative statistics, coupling with the use of remote sensing images and other spatial data, this article discusses the urban agglomeration of oasis on the northern slope of the Tianshan Mountains in an arid area, and conducts the researches on its city scale, spatial distribution and individual form from 1990 to 2005. The result shows that it has loose hierarchical scale structure and polarization trend of population distribution while its hierarchical scale structure tends to mature. Under the influence of natural conditions, the spatial layout of urban agglomeration of oasis has macro characteristics that suggest cities distributed along oasis edges (dense or sparse), spatially expand along rivers, and cluster around traffic branches. The connectivity among the cities is high and shows an internal organization form of a banding distribution. The whole spatial shape of the internal structure of cities presents a “dumbbell” form, with mononuclear phenomenon receding and multi-nuclear appearing gradually. Individual cities spatially expand along rivers, portraying a long strip appearance. It indicates that the urban agglomeration of oasis shows regular and close structure but with a tendency to be complicated form and the loose structure. In the development of urban agglomeration, the authors recommend that the development of the city with good economic development conditions should be strengthened, and more attention be put into regional planning.