关键词: 变化轨迹分析, 耕地, 遥感, 驱动力, 南京市

Abstract: With rapid economic development, urbanization of Nanajing is accelerated vigorously, thus causing tremendous change in land use in the region. Based on Landsat MSS/TM images of the region from 1985 to 2010, land use data of the past years were acquired using the maximum likelihood method and sorted into two categories, farmland and non-farmland. Based on the classification, the land was further sorted into five groups, that is, permanent farmland, permanent non-farmland, transforming into farmland, transforming into non-farmland and tentative farmland, in light of their natures of land use, showing trends of the change in land use.  Spatio-temporal dynamics of the landscape patterns of the five groups of land in change wasere analyzed by means of using the percentage of Landscape iIndex (PLAND), and the Interspersion and juxtaposition Iindex (IJI) to show spatio-temporal trajectories of the farmland in expansion and desertion. Results show that (1) the farmland decreased in area by 40.42% from 1985 to 2010; (2) permanent farmland in Azimuth 3 was the highest in area, accounting for 56.89% of the total; transformation into non-farmland occurred  mainly in Azimuths 1, 6 and 8, which reveals the main direction of urbanization; (3) permanent farmland was mainly distributed in Liuuhe District, making up 895.92km² and transformation into non-farmland occurred mainly in Jiangning District; (4) permanent non-farmland was mainly located in the urban region while permanent farmland was in the opposite direction; (5) permanent farmland was still in dominancy, land under transformation into non-farmland was highly fragmented and tentative farmland was not stable in area and susceptible to desertion  and even degradation; and (6) shifting of the population and industrial centers, economic development, policies and urban expansion were the key factors significantly affecting change in farmland.

Key words: trajectory analysis, farmland, remote sensing, driving force, Nanjing