土地利用和地形因子影响下的西藏农业产值空间化模拟

农业产值空间化模拟是客观评价农业生产效率的基础，是科学制定农业发展政策的依据。该文综合运用地统计学方法和地理信息系统空间分析功能，根据海拔高度与农业产值不同的拟合关系将西藏划分为Ⅰ型和Ⅱ型地区，分析了两类区域土地利用和地形因子与农业产值的关系。在此基础上，以土地利用为指示性因子，综合考虑地形因子对农业产值空间分布的影响，运用因子相乘的方法实现了多源数据的融合，建立了西藏农业产值空间化模拟模型。分析模拟结果：Ⅰ、Ⅱ型12个检验样本中共有8个县相对误差小于30%，模拟结果比较理想。同时，该模拟结果能够较好地反映西藏农业整体发展水平低，80%以上的农业用地每平方公里产值低于5400元， “一江两河”流域和昌都地区农业产值相对较高的实际情况。这有助于正确认识西藏的农业发展状况，为区域可持续发展服务。

Simulation of distribution of agricultural output value influenced by land use and topographical indices in Tibet

Simulation of distribution of agricultural output value is a basis of objective assessment of production efficiency of agriculture and of making policy of the development of agriculture. According to the different relationships of altitude and output value of agriculture, counties of Tibet were plotted off two patterns, and the relationships between output value of agriculture and land use, topographical indices were analyzed by integrating geo-statistics method and spatial analysis function of geographic information system(GIS). Taking land use as indicator factors, considering the effects of topographical indices on spatial distribution of agriculture output value, the simulation model of distribution of agriculture output value were established based on fusing multiple source data by multiplication. Results show that the relative error of 8 testing samples in total 12 is lower than 30%, so the result is reliable. Furthermore, the simulation results reflect the distribution of agriculture output value in Tibet objectively: the development of agriculture in Tibet is very low, and there is more than 80% of Tibetan land in which output value of agriculture is lower than 5400 RMB/km², and the agriculture output value in Yarlung Zangbo Jiang, Lhasa he and Nyang Qu drainage area and Qamdo Diqu is higher than that of other region. So the simulation of distribution model is helpful to recognize agricultural development level of Tibet and has profound implications for regional sustainable development.