Application Research On DTM Data And ETM+images In The "Mineral Prospective Survey Of Xunyang-Baihe Area"

Through the topographic map vectorization of the study area,this paper produces and analyses three-dimensional digital terrain map(DTM) and extracts of linear structure on the basis of the project of "the mineral prospective survey of Xunyang-Baihe area in Shaanxi" in China geological survey,processes and analyses ETM + remote sensing images,statistical calculates the best bands combination,extracts the geological anomalous body by ratio analysis and principal component analysis,in the end generates three-dimensional geological map by combining two with digital geological maps to make geological information more user-friendly.Through research and analysis,the understandings are as follows:1.Through the production of DTM data in the study area,the author analyzes error sources in the process of DTM data prodution and countermeasures.The vectorization error sources of topographic maps has the error generated by medium deformation of the original topographic maps data,the errors generated by scanning vectorization of topographic maps, the errors generated by digital readings and a variety of errors generated by digital operation. In order to reduce the these errors,the erros are controlled from the beginning of vectorization, the true value approached as much as possible in the process of vectorization.2.DTM data in the study area are produced,the linear structures are extractesin the study area as an example of Baihe county map of the most complex structure.The consistent basic form and the same trend are found between them by the careful comparison with the linear structure in Baihe county geological map,the same degree can be as high as 80%,this shows the extraction of linear structure based on three topographic maps in the region has a certain direction significance,especially in regard to extraction of fault.At the same time unconsistent some areas are questioned,the information of regional geological map can be more precise through verification once again in the field.3.Analysing and pre-processing ETM + images in the study area,the best band combination,ratio analysis and principal component analysis of 743 is gained by statistical analysis.Marked table of lithological interpretation and tectonic interpretation are established in the study area,and linear structure and circular structure map are extracted as an example of Baihe county map.Volcanic geological anomaly body in the Shenhe area is extracted by ratio analysis,and the different places of the distribution scope are found by comparing with geological maps of Xunyang county map,it is recommended that verification in the field should be on the basis of research finally.4.Using production DTM data for the bottom,remote sensing images and digital geological map dealt with and analysed for texture,the two are nested,three-dimensional topographic geological map of Xunyang county map is eventually iproduced from an example of Xunyang county map.