基于分形维数的长汀县土地利用动态变化

Dynamic change of land use in Changting County based on fractal dimension

以福建省长汀县为研究区域,基于遥感和GIS技术的支持,对研究区2000年、2009年、2016年的土地利用结构及分形动态进行分析。研究表明:经过多年的治理工作,长汀县的土地覆被情况有了很大的改善,林地面积不断增加,裸地面积持续减少。各土地利用斑块形态具有明显的分形特征,2000—2009年,耕地、建设用地分维值呈增加趋势,空间形态趋于不规则;林地、裸地和水域分维值减少,空间形态趋于规则。2009—2016年,耕地、裸地和水域斑块分维值呈上升趋势,空间形态趋于不规则;而林地和建设用地斑块分维值趋于下降,空间形态趋于规则。总体上土地利用分维值仍有增大的趋向,土地斑块的稳定度趋于下降。土地利用的复杂性和稳定性受到人为因素影响强烈,合理协调人地关系,避免治理成效出现反复,仍然是水土流失区治理的关键。

Background,aim,and scope Taking Changting County of Fujian Province as the research area and the support of remote sensing and GIS technology,the land use structure and fractal dynamics of the study area in 2000,2009 and 2016 were analyzed to provide the basis for future rational land use planning in Changting County.Materials and methods Based on the multi-temporal remote sensing images acquired by Landsat series satellites,this study uses ENVI 5.1 software to interpret the land use types of the study period and calculate the perimeter and area of each kind of patches.Finally,the fractal formula is used to calculate the land use types.Results The research shows that after many years of governance,the land cover in Changting County has been greatly improved,the area of forest land has been continuously increased,and the area of bare land has been continuously reduced.The fractal features of land use patches have obvious fractal characteristics.From 2000 to 2009,the fractal dimension values of cultivated land and construction land tended to increase,and the spatial patterns tended to be irregular.The fractal dimension value of forest land,bare land and water area decreased and the spatial shape tended to rule.From 2009 to 2016,the fractal dimension values of cultivated land,bare land and water patch tended to increase,and their spatial forms tended to be irregular.However,the fractal dimension of forest land and construction land tended to decline,and the spatial morphology tended to be regular.In general,the fractal dimension of land use still tends to increase,and the stability of land patches tends to decline.Discussion The complexity and stability of land use is strongly influenced by man-made factors.It is still the key to harnessing the soil and water loss areas that reasonably coordinating the relationship between man and land and preventing the recurrence of governance achievements.Conclusions The use of fractal methods can better quantitatively express the morphological changes of land use.Recommendations and perspectives The fractal theory can be used to quantitatively express the dynamic changes of land use types from a new perspective and provide a well reference for the dynamic assessment of land use in soil erosion areas.