地形对兰州市中心城区土地利用空间格局的影响

Impact of topography on land use pattern in the central area of Lanzhou City

选择兰州市中心城区为研究区域,结合分类决策树自动提取的土地利用信息,利用DEM数据获取地形因子,定量分析兰州市各地形分级单元内的土地利用空间格局特征.结果表明:80%以上的城乡及工矿用地以及90%以上的水域分布在较低、较缓的区域,60%的林地和草地分布在较高、较陡的区域,约50%的未利用地分布在高程<2 000 m、坡度<15°区域内,可以考虑一定程度的开发利用;高程<1 600 m,坡度5°~8°区域内,景观最为破碎,形状最不规则,生态环境最为脆弱;高程1 600~2 000 m、坡度8°~15°区域内,土地利用景观类型最为丰富;高程>2 800 m的区域内,同类型土地利用景观不断集中、合并,土地利用景观的整体性最强.

The central areas of Lanzhou City were chosen for study and classification, a regression decision tree was constructed to extract land use information automatically and then terrain factors were calculated based on DEM. The character of land use was analyzed with the changes of elevation and slope. The results showed that more than 80% of residential and industrial land and more than 90% of water occupation were distributed in the lower and more moderate areas, 60% of the forest and grassland in higher and steeper areas, about 50% of the unused land was located in the elevation range of less than 2 000 m and slope of less than 15°,which could be considered for a certain degree of exploitation. The region in an elevation range of less than 1 600 m and slope ranging between 5° to 8° appeared the most tattered in landscape, with the most irregular shapes and most fragile ecological environment. The most rich type of landscape was in the elevation range from 1 600 m to 2 000 m and slope ranging between of 8° and 15°. The same types of land use appeared gathering and merging within the range greater than 2 800 m with the best effect of integration.