基于多特征SVM的昆明市城市森林时空分布信息提取

Information Extraction of Temporal and Spatial Distribution of Urban Forest in Kunming Based on Multi-feature SVM

采用2017年昆明市主城区Landsat TM/OLI及DEM数据,采用SVM分类方法,对比不同多特征组合的分类精度筛选出森林提取的最佳特征组合,并由此得到2000、2010及2017年昆明市主城区森林分布,分析3期森林的总面积、不同海拔森林面积分布和植被覆盖度变化。结果表明,光谱、纹理以及地形特征的多特征组合为城市森林提取的最佳组合(精度为92.69%);2000—2017年昆明市主城区森林总面积呈上升趋势,海拔低于2 000 m区域的森林面积逐年减少,而高于2 000 m区域的森林面积逐年增加;随时空变化呈现出低植被覆盖度及高植被覆盖度面积增加,中植被覆盖度及较高植被覆盖度面积减少的趋势。

Based on the data of Landsat TM/OLI and DEM in main urban area of Kunming in 2017,the SVM classification method was used by comparing the classification accuracy of different multi-feature combinations to select the best feature combination for forest extraction and obtain the distribution of urban forests in 2000,2010 and 2017.The analysis for the differences of total area,the distributions of forests at different altitudes,and the changes of vegetation coverage in three phases showed that the combination of spectral,texture,and topographic features was the best for urban forest extraction(with an accuracy of 92.69%).The total area of forests in main urban area gradually increased from 2000 to 2017,the area at elevations below 2000 m decreased and the area above 2000 m increased gradually.The area of low vegetation coverage and high coverage showed the increasing trend,and the middle coverage and higher coverage was decreasing.