The Study On The Landscape Pattern Of Land Use In Xiangyang City

Based on the LandsatTM image data (Xiangyang City) in2002and2010, this paper used ERDAS9.2to correct satellite image and enhanced image. After that this paper made the supervised classification and divided into ten land use types such as rainfed croplands, nonirrigated farmland, forest land, shrubland, mosaic vegetation cropland, mosaic cropland vegetation, grassland, urban land, rural residential area, other construction land, water bodies and unused land. This paper analyzed and extracted the area of various land use types by using the spatial analysis function of arcgis10.0, and made the land-use landscape pattern tendency chart of Xiangyang city by using GIS software in order to analyze the transfer situation of land utilization type area. The writer choose relevant landscape pattern indexes according to the specific situation of study area. Based on the landscape pattern index model this paper has carried on the quantitative research of the evolution of the landscape pattern of Xiangyang city. Finally, the writer discussed the driving mechanism of land use dynamic change of landscape pattern, and analyzed the two aspects of natural factors and human factorsand its influence on landscape pattern change in the study area.This paper drew the following conclusions:(1) The land use landscape of Xiangyang city has changed dramatically in the last ten years. Patch number of the rural residential areas showed trend of increase, and the most obvious part is mosaic vegetation cropland change. One of the biggest landscape change was mosaic vegetation cropland, and the centre of gravity was skewed clearly to north-west. Mosaic vegetation cropland zone landscape more fragmented, while the patch shape tended to simple. The farmable forest land was reclaimed as the pressure of demand for food increases. YiCheng was the center of gravity for reclamation. Forestland area greatly increased as the policy turned farmland to forest. Average patch area was the largest urban area and the average patch area of construction land has increased in the last ten years.(2) The landscape patch density,total length of border, edge density, shape-mn and Simpson diversity index showed a tendency of increase,but contagion index and landscape dominance index decreased. (3) From the perspective of the analysis of natural driving factors, the slow decline of average annual precipitation and annual average is relative with the slow increase of its annual average temperature and annual sunshine time in the past ten years.(4) In the human driving factors, an increase of the number of population is the main cause of land-use landscape pattern change. This performance is most obvious in mosaic vegetation cropland mixed zone. More and more population led to a surge in construction land area. The landscape fragmentated further. Forestland area has a large increase as the policy of returning farmland to forest.