基于改进决策树的城市不透水面遥感监测及分析研究

发布时间：2018-01-19 13:21

本文关键词： 不透水面决策树分类空间分析城市扩张城市蔓延景观格局　出处：《昆明理工大学》2013年硕士论文　论文类型：学位论文

【摘要】：城市化是20世纪以来最为显著的人类活动特征,随着人口的快速增长以及科技的飞速进步,人类对区域土地的改造速度与需求与日俱增,城市化进程日益加剧。不透水面作为高速城市化进程中人为改造地表活动的特征产物,其面积的迅速增加很大程度上影响着区域生态环境变化并主导着城市景观格局演变过程。作为城市的基质景观及典型地表类别,不透水面常被用于地表覆被动态监测、城市水文模拟、非点源污染负荷估算、热环境效应、区域气候变化、城市扩张监测以及城市生态系统评价等多个方面。本文以昆明市为研究区,在遥感、GIS以及景观格局分析软件等支持下,采用改进决策树方法提取不透水面信息并应用皮尔逊卡方检验、香农熵等统计分析模型进行空间扩张定量分析,从政策导向、地形等方面进行扩张驱动力分析并从城市生态景观层面进行区域景观格局分析。文章基于研究区2002、2006和2010年三期Landsat ETM+影像开展研究,选取影像的3、4、5、7波段以及图像增强处理过程中主成分分析后的第一波段和归一化植被指数运算后的植被信息增强波段共6个波段进行影像组合。采用基于CRUISE算法的决策树分类方法进行研究区土地覆被类别解译,并采用改进归一化水体指数以及基于植被覆盖度的不透水面密度分割图进行掩膜处理,进一步提高解译精度,得到研究区三个时期的土地利用分类信息。利用空间象限法将研究区划分为8个方向区域,引入皮尔逊卡方检验、香农熵、优势度、扩张强度指数等分析模型从方向区域、发展阶段及总体情况等三个层面进行研究区不透水面空间扩张定量分析。结果显示,各方向区域不透水面扩张速度和扩张趋势存在较大差异,体现出空间扩张的不均衡性。2002～2006年间,城市不透水面扩张受政策、规划等因素的约束较小,发展较为自由但扩张速度相对缓慢。2006～2010年间,其增长速度有所加快,扩张优势度有较为明显的提升,但自由性和蔓延性有明显下降,表明城市在快速发展的同时逐渐向紧凑型、集约型方向靠拢。从区域扩张的总体情况来看,研究区有较高的总体自由度和蔓延度,但两者都呈减缓趋势,此外其扩张优势度较低,表明区域土地仍未得到有效利用。利用研究区DEM数据与不透水面信息进行叠加分析。从高程分布看,绝大部分的不透水面位于1803米到2022米高程范围内,其扩张趋势为由发展趋于饱和状态的低海拔区域逐渐转向开发难度较大的较高海拔地区,但目前低海拔区域仍是主要扩张区域。从坡度分布看,绝大部分的不透水面位于2°到15°范围内,并表现出不透水面面积随坡度的上升而下降的总体趋势。2-6°为主要扩张区域,15°以上的土地建设开发难度明显增加,范围内不透水面面积增长较少。选取斑块类型和景观水平指数进行研究区景观格局分析。从景观水平看,研究区斑块总数由2002年的63395上升到2006年的77244继而下降到2010年的69629,区域经历了斑块破碎加剧进而逐渐聚合的过程。其中,水体、植被和夹杂稀疏植被的裸地部分的斑块数为先上升后下降,无植被覆盖的裸地部分的斑块数呈持续下降趋势。区域内不透水面斑块数先下降后上升,其经历了从众多离散分布的较小面积到逐渐趋于集中的较大面积斑块区域的变化过程,此外其在发展过程中与其他景观的临接关系减弱,毗邻的景观类型趋于单一,较大程度影响了区域生态多样性。
[Abstract]:The city is the most since twentieth Century the characteristics of human activities significantly, with the rapid growth of population and the rapid development of science and technology, human transformation speed and the demand for land of city urbanization increasingly grow with each passing day,. The impervious surface as the characteristic product of the high-speed city in the process of human transformation of surface activity, rapidly increasing its area of great influence on the regional ecological environment evolution process and dominate the city landscape pattern. As the matrix landscape in the city and the typical surface types, impervious surface is often used for land cover dynamic monitoring, city hydrological simulation, estimation of non-point source pollution load, thermal environment effect, regional climate change, many aspects of city expansion monitoring and the city ecosystem evaluation.
This paper takes Kunming city as the study area, remote sensing, GIS and landscape pattern analysis software support, the improved decision tree method to extract impervious surface information and using the Pearson chi square test was used to analyze the spatial expansion of quantitative Shannon entropy statistical analysis model, from the aspects of policy guidance, terrain analysis and driving force of expansion the analysis of regional landscape pattern from the city ecological landscape level. The study area in 20022006 and 2010 three Landsat ETM+ images based on the image, select the 3,4,5,7 band and the image enhancement processing principal component analysis in the process of the first band and normalized difference vegetation index after computing the vegetation information enhancement band common 6 band image using decision combination. The tree classification method based on CRUISE algorithm of land cover classification interpretation, and by using the improved normalization index and based on The impermeable surface density partition map of vegetation coverage is used for mask processing to further improve the accuracy of interpretation, and the classification information of land use in the three period of the study area is obtained.
The study area is divided into 8 regions using direction space quadrant method, using Pearson chi square test, Shannon entropy, dominance, expansion intensity index analysis model from three aspects of the development direction of regional, stage and the overall situation is studied through analysis of surface area quantitative spatial expansion. The results show that the direction of the impervious the water expansion rate and expansion trend differences, reflects the imbalance of.2002 ~ 2006 years of city spatial expansion, impervious surface expansion by the policy, planning and other factors are less constrained, but the expansion rate of free development is relatively slow.2006 ~ 2010 years, its growth rate has accelerated the expansion degree has obvious advantages the promotion, but free and spreading has decreased significantly, that in the rapid development of the city gradually to the compact, close to the intensive direction. From the overall situation of regional expansion, research The region has a higher overall degree of freedom and spread, but both show a slow trend, in addition to its low expansion advantage, it shows that the regional land has not been effectively used.
Using the DEM data of the study area and impervious surface information overlay analysis. From the view of the distribution of elevation, most of the impervious surface is located 1803 meters to 2022 meters elevation range, its expansion trend from low altitude regional development tends to saturation gradually turned to the difficulty in the development of higher altitude, but the low altitude region is still the main expansion area. From the view of the distribution of slope, the vast majority of impervious surface is located at 2 degrees to 15 degrees range, and showed the general trend of the impervious surface area decreased with the slope of the rise.2-6 degrees as the main expansion area, more than 15 degrees of land development is a significant increase, impervious surface area increased less range.
Patch type and landscape level index of landscape pattern analysis. From the landscape level, the total number of patches in the study area increased from 63395 in 2002 to 77244 in 2006, then dropped to 69629 in 2010, the region has experienced the process of fragmentation intensified and gradually polymerization. In the water, vegetation and bare soil part with sparse vegetation the number of patches was increased after the first drop, no part of the bare patch number of vegetation coverage showed a declining trend. Within the area of impervious patch number decreased and then increased, the experience from many discrete distribution is relatively small to the change process of large area plaque area gradually tends to focus on the development of the process and the other landscape adjacent relationship weakened, adjacent landscape types tend to be single, greatly influenced the ecological diversity of the region.

【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P237

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