基于矢量属性的宁夏中部干旱带土地利用变化信息挖掘

目的]增加对土地利用变化矢量属性的认知,进一步挖掘潜藏于土地利用变化中的特征和规律,丰富土地利用变化研究方法,为区域土地资源调控提供参考依据。方法]基于土地转移流视角,提出土地转移率和土地转移链概念,采用Landsat MSS/TM/ETM遥感影像数据,对宁夏中部干旱带同心县的土地变化过程进行研究。结果]1978—2015年同心县耕地和草地比例增大,未利用地减少。区县尺度上土地转移率渐次降低;类型尺度上,耕地转移率先升后降,草地转移率先降后升,未利用地转移率呈"降—升—降"特征。1978—1987年的土地转移流以草地转未利用地为主,1987—1996年则呈现多元特征,1996年表现为退耕还林还草和对未利用地的改造利用。1978—2015年土地利用转移围绕着耕地的流失与保护进行,土地转移单向链以31型(草地转耕地)和61型(未利用地转耕地)为主,往复链以Ⅱa型为主,主要是161型(耕地—未利用地—耕地)和131型(耕地—草地—耕地)。结论]同心县土地利用变化存在较大份额的"往复链"。在土地资源开发与管理中要重视往复链所揭示的内涵并采取针对性措施。

Information Mining in Arid Area of Central Ningxia Hui Autonomous Region Based on Vector Properties of Land Use Change

Objective] This paper was aimed to deepen the cognition to the vector properties of land use change,to further extract the profundity information in the characteristics and the rule of land use change,and to enrich the land use change research methods,to provide relevant reference for the regulation of land resources.Methods] On a perspective of land use transfer flow,two concepts termed land use transfer rate and the land use transfer chain were introduced.Data of MSS/TM/ETM remote sensing image were used to make a case study of land change process in Tongxin County in arid area of central Ningxia Hui Aotonomous Region.Results] Cultivated land and grassland had increased in the study region,however,the area of unused land had reduced during 1978-2015.At countywide scale,land use transfer rate had decreased gradually in Tongxin County.With respect to the land use transfer of different lands,the transfer rate of cultivated land increased firstly and then decreased;land use transfer rate of grassland reduced firstly and then rose;and land use transfer rate of unused land experienced a variation of deduce-rise-deduce in Tongxin County.From 1978 to 1987,grasslands were mostly transformed to unused lands in Tongxin County.From 1987 to 1996,the land use transfer flow was diversified.Since 1996,grasslands were expanded in the processes of cultivated land transformation and the unused land was also amplified,for it was exploited attentively.From 1978 to 2015,the transformation of land use in Tongxin County was mainly referred to the loss and protection of arable land.Among the transformation types,one-way chain had two main types referring to 31 (grass turn arable land) and 61(unused cultivated land);reciprocating chain called Ⅱ a,mainly had the types of 161 (cultivated land-unused-cultivated land) and 131 (cultivated land-grassland-cultivated land).Conclusion] There existed a great proportion of "reciprocating chain" of land use change in Tongxin County during 1978 2015.In the future,more attention should be paid to the connotation revealed by the called reciprocating chain of land use change,and relevant countermeasures should be taken in the development and management of land resources.