Effects of Spatial Grain Size on Landscape Pattern of Qingpu District in Shanghai

摘要

In this paper,the effects of spatial grain size on landscape pattern of Qingpu district are discussed under two levels of class and landscape. To reveal the effects of grain size on landscape pattern,a series of rastergraphs with different grid cells are constructed based on majority rules using data of TM satellite remote sensing and GIS skills. Software Grid module of Arc/Info Fragstats3.3 was used as the landscape pattern analysis tool. The conclusions are drawn as follows: (1) There are obvious effects to respond to different grain sizes in class-level and landscape-level. Among the 7 landscape types,roadland and inhabitantland change significantly with different grain sizes ;the indices of LSI,CLUMPY,NP are sensitive to grain size contrary to SIDI,SIEI,PAFRAC. Generally,dominant types of landscape were strengthened with increasing grain size; The regular landscape isn't sensitive to changes with increasing grain size. (2)The curves of indices have scale inflexion and most of them appear at 40m,60m,80m and 120m.The appropriate grain size should be chosen in the first scale domain,the range of appropriate grain for landscape indices of Qingpu district was 30m to 40m. (3) The trend of FRAC_MN and PAFRAC is adverse as the increase of grain size. This shows the limitation of the use of indices to quantify the landscape pattern at a certain degree.