Processing remotely sensed data for geological content over a part of the Barberton Greenstone Belt, Republic of South Africa.

[摘要] Various methods and techniques developed by researchers worldwide forenhancement and processing ATM, MSS· and TM remotely sensed data aretested. on LANDSAT 5 Thematic Mapper data from a part of the BarbertonGreenstone Belt straddling the border between the Republic of South Africa andthe Kingdom of Swaziland.Various enhancement techniques employed to facilitatethe extraction ofstructural features and lineaments, and the findings Of the ensuingphotogeologlcal interpretation are compared with existing geological maps~Methods for the detection of zones of hydrothermal alteration. are alsoconsidered.The reflectance from vegetation, both natural and cultivated, and the possiblereduction of the interference caused by this reflectance, are considered in detail.Partial unmixing of reflectances through the use of various methods andtechniques, some of which are readily available from the literature, areperformed and its effectiveness tested. Since large areas within the study areaare covered by plantations, the interfereiice from the two types of vegetationpresent (i.e. natural and cultivated), were initially considered separately. In anattempt to isolate the forested areas from the natural vegetation, masks derivedthrough image classification were used to differentially enhance the variousfeatures.Results indicate that the use of any particular method to the exclusion of allothers will seriously limit the scope of conclusions possible through interpretationof the information present. Enhancement of information in one domain willinadvertently lead to the suppression of information from one or more of the coexistingdomains. A series of results from a sequence of procedures interpretedin parallel will in every case produce information of a higher decision makingquality.

[发布机构] University of the Witwatersrand