Estimation of Forest Canopy Closure Through Fuzzy Classification of Satellite Data

• Main Authors: Wang, Yun-Hao, 王韻皓
• Other Authors: Chiao, Kuo-Mu
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/21150722746438826141

碩士 === 國立臺灣大學 === 森林學系 === 84 === Forest canopy closure is an important index on ecological study and forestmanagement . Forest canopy closure is closely related to erosion control, water and soil conservation,watershed runoff estimation,which is also used to assess wildlife habitat and forest biomass. In the early years, aerial photography were usually usedto interprete forest canopy closure. However, after the launchofLandsat-1 in 1972, using remote sensing image to estimate forestcanopy closure is widely studied. In general, regression analysis is used to estimate forest canopy closure. But this method is not appropriate for highly complex landscapes, where forest mixtures and terrain roughness may obscure the existence of homogeneous samples. Fuzzy classific- ation approach solves the problem of choosing homogeneous samples . Unlike traditional classification method which is one- pixel-one -class, thesamples of fuzzy classification are represented by fuzzy membership grades, hence the classification accuracy is im- proved. The study area of this research locates at Chi-Tou, Experimental Forest of National Taiwan University. A Landsat Thematic Mapper scene of this area was used in the study. In thisstudy, geometric correction and radiometric correction were done first to improve the quality of the TM imagery. After preprocessing,seventy-two plots with a size of 3*3 pixels were drawn from theTM imagery. Fourteen vegetation indices including TM1、TM2、TM3、TM4、TM5、 TM7、GVI 、NDVI、R43、R54、R32、VI43、VI45、VI42 were derived from these plots,and stepwise discriminant analysis was used to select more important indices. Those indices were used as input data for the fuzzy classification approach and the minimum distance pattern classification approach to estimate forest canopy closure , and the results of these two approaches were compared.