Temporal-spatial Grading Diversification of Land-cover at Landscape Level in Guangzhou since 1990

Four TM remote sensing images of Guangzhou in 1990, 1995, 2000 and 2005 were taken as data for the present study. The images fully covered the area of Guangzhou. The data sources of land-cover landscape were translated under manual and un-supervised interpretations with GIS software. Two highways were set as the lines of transects by buffer zone techniques. One transect is along north-south direction, and the other is west-east. Meanwhile, the radiative transects were set around the city center, where it was encircled by Huancheng highway. The buffer zone width was five meters. All data sources of land-cover landscapes were cut out by those transects, respectively, and all landscape indices were calculated based on these land-cover landscapes cut out. Based on these data the dynamics of land-cover landscape and their characteristics were analyzed, and results revealed that there were obvious diversifications in transect directions and different radiative transects. The results of quantity structure of land-cover landscape in the study area showed that excessive land-use has been controlled, and urbanization had being experienced development reasoning since 1995. But the diversity of land-cover landscape along the west-east decreases constantly and fragmentation of landscape patches is being expedited. The analyzed results of radiative transects showed that there are many satellite cities around the city center of Guangzhou, and intensity to disturb land-cover landscape is decreasing from the city center to the suburban areas while the diversification in different directions along N-E and S-E is not significant. In southern part, variations of indices of land-cover landscape foretell that sea area is being disturbed by new plan of city development.