基于"3S"技术的奉节县喀斯特石漠化调查及精度评价

石漠化问题是我国西南地区生态环境建设的难点和重点．以TM遥感图像为基础，用实地调查与3S技术相结合，以人机交互式判读为主的方法，对奉节县石漠化现状进行解译并得出分级结果．采用混淆误差矩阵和相对误差法对分级结果作精度评价．结果显示，在全县2198．88km^2碳酸盐岩层中，无石漠化面积为683．70km^2，潜在石漠化面积741．25km^2，石漠化面积773．92km^2，石漠化发生率为35．2％．其中轻度、中度、强度、极强度石漠化面积分别为266．74km^2、312．48km^2、178．60km^2、16．10km^2，占土地总面积的6．5％，7．6％，4．4％、0．4％．石漠化强度分级结果的总精度为95．3％，图斑面积平均相对误差为1．96％，调查结果符合精度要求．

Investigation and Evaluation of Rocky Desertification Based on "3S" Technology in Fengjie County

Rocky Desertification is the difficulty and key-point of ecological environment construction in southwest of China.Based on the TM image,the authors analyzed the state of rocky desertification and obtained a classification in Fengjie County,Chongqing with the on-the-spot investigation,the 3S technology and the cross-interpretation between people and computer.And the accuracy of the classification was evaluated by confusion error matrix and the relative error.The results show that,in the 2198.88 km2 Carbonate area of this County,the not obvious rocky desertification area is 683.70 km2,the latent rocky desertification area is 741.25 km2 and the rocky desertification area is 773.92 km2.The rocky desertification formation rate is 35.2%.The light,the moderate,the intensity and the very intensity rocky desertification area is 266.74 km2,312.48 km2,178.60 km2 and 16.10 km2 respectively,with the percentage in the county-wide area of 6.5%,7.6%,4.4% and 0.4%.The results of rocky desertification investigation are credible with the accuracy of 95.3% and the relative error of 1.96%.