基于GIS和分形的云南省富宁县交通网络研究

Study on the Road Network of Funing County,Yunan Province Based on GIS and Fractal theory

应用ArcGIS数字化了云南省富宁县扫描地图,获得了该县各等级公路的矢量数据;以县城为中心,计算出该县公路网的长度-半径分数维为1.409 9,结果显示该县公路网密度分布具有显著的分形特征,从县城向周围衰减;将公路矢量数据栅格化,计算出该县的路网分形维数为1.050 5,低于路网规划的1.585;山地地形是该县路网覆盖度较低的主要成因,基于SRTM DEM数据,得出该县坡度≤6°的土地仅占6.435%,地形崎岖导致公路建设的难度与成本增加;最后应用条带剖面法(swath profile),分析了该县广昆高速公路沿线的地形特征,总体地形自云南高原向广西丘陵降低,起伏大,沿线地貌可划分为西部小起伏中山、中部小起伏低山和东部小起伏低山丘陵三段。

using ArcGIS to digitize the scanned map of Funing County,Yunnan Province,and the vector data of of roads with different ranks in this county was obtained;With the county seat as the center,the value of Lenth-radius dimension is 1.409 9,and the results show that the distribution of the density of the road networks,declined from the center to the peripheral,has remarkable fractal characteristic;by converting the vector data of the road networks to raster,the grid dimension of the county was calculated to be 1.050 5,and lower than the value of 1.585 designed for the planning of the road networks,and the rough terrain increases the difficulty and the costs of road building.With SRTM DEM,the land with slope≤6° only occupies a portion of 6.435%;Finally,the swath profile was used to analyze the topograhy along the highway from Guanzhou to Kunming in this county,the graph of the swath profile showed that the elevation along the highway declined from Yunnan plateau to Guanxi hills and the relief amplitude mostly between 300 m to 500 m,and three categories of the landform along the highway were iendtified as western middle mountains with small relief,the central lower mountain with small relief and eastern lower mountain and hills.