基于小波变换的武汉市城乡边缘带识别

Identification of a Rural-urban Fringe Based on Wavelet Transform—A Case Study of Wuhan

对城乡边缘带的空间识别是城乡边缘带研究领域的热点。针对现有研究普遍存在的指标选取过于繁琐、大多采用阈值设置界定边界、以及对边缘带内、外边界分别提取等不足,在对土地利用程度综合指数与城乡边缘带的关系进行理论及样带分析的基础上,将小波变换方法引入城乡边缘带识别的研究中,以遥感影像为基础数据,选用土地利用程度综合指数定量评价土地利用程度,基于小波模极大值检测原理检测由综合指数数据序列变换得到的小波系数突变点群,依据突变点群的空间格局识别城乡边缘带内、外边界。以武汉市为例的实证研究表明,该提取方法严谨、高效。

The identification of the rural-urban fringe is a hotspot in the rural-urban fringe research field.However,fussy indictors,threshold value methods,and identifying fringe respectively are usually used according to existing research approaches.We however,introduced the wavelet transform method to identify rural–urban fringe through detect mutation point group of LUDCI values based on modulus maxima of wavelet transform,after an analysis of the relationship between land use degree comprehensive index（LUDCI）and rural-urban fringe.Along each profile from central city to suburb,the inner boundary of a rural-urban fringe is where a mutation point group appears,while the external boundary is where mutation point group disappears.Wuhan is experiencing rapid urbanization,and therefore were chosen to implement a case study.The db3 Daubechies wavelet function was selected as the mother wavelet,and wavelet transform was scale 3.The visualization of mutation point detection results were performed using ARCGIS.These case study results suggest that the two rural– urban fringe boundaries could be identified together.Our results show that this method is a stricter and more efficient approach for identifying rural-urban fringes than other methods.