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Geology
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Requirements of Remote Sensing data for geological applications
A. K. Gupta, K. Genesha Raj
National Natural Resources Management System
Indian Space Research Organisation Headquarters
Bangalore, India
Abstract
Remote sensing is very useful in various geological applications such as lineament and litho logical mapping, geomorphologic mapping and their applications to mineral/oil/ground water and engineering geological fields. However at present the applications of satellite remote sensing data is limited to regional scale geological mapping. An attempt has been made to analyse the requirements of remote sensing data for various geological applications. Problems in the usage of remote sensing data are identified. Requirements of remote sensing data for its applications in terms of spatial/spectral resolution, multidata remote sensing, frequencies of mapping, multi-level remote sensing. Criticality of parameter for mineral/oil/ground water and engineering geological applications etc. are worked out and compiled in a from of table. The work is considered to be useful for working out sensor specifications for future satellites. Factors such as effect of clouds and shadows. topography etc. also need due consideration for designing sensor parameters.
Introduction
Remote sensing is very useful for various geological applications such as litho logical, structural, geomorphologic mapping: ground water mineral, oil exploratiosnand engineering geological applications etc. Aerial photographs have been used for a long time for geological interpretations and their utility is established. Main advantages of aerial photographs are high spatial resolution and stereo view. Of late satellite remote sensing has become quite popular because of its synoptic view, high repetitively and multi spectral sensing in Visible to Microwave range. As the satellite or aerial remote sensing do not totally fulfill the requirements for geological studies and have their own inherent limitations, (i.e. inadequate spectral/spatial resolution, receptivity areal coverage etc.) Realising limitations of available remote sensing data for geological applications. All the parameters on which information is frequently required in various geological exercises such as geological and geomorphological mapping. mineral, oil and ground water explorations, engineering geological applications etc. have been considered for working out requirements of remote sensing for their study.
Methodology
An analysis has been made to work out requirements of remote sensing for study of various geological parameters such as rock types, folds, faults, fractures, shear zones, gossans alteration zones, construction materials, needed for mineral, oil, ground water engineering geological and other applications. The requirements of remote sensing for mapping above parameters differ with reference to scale of mapping e.g. small resolution data may be appropriate for regional scale mapping but for detailed mapping we may require high resolution data. The remote sensing requirements may
also very with reference to particular applications e.g. for systematic geological surveys, 10-20m resolution satellite data may be good enough but for engineering geological projects we may need large scale aerial data. Also in some cases we may need data both from satellites and aircraft e.g. for semi detailed geological surveys.
Keeping all the above pointing in view requirements of remote sensing (for study of various geological parameters) in terms of spatial resolution, need of aerial/satellite/aerial remote sensing, frequency of mapping and surveys carried out at present to get the desired information are worked out in detail. Priority has been worked out for all the geological parameters for the purpose of mineral/oil/ground water and engineering geological applications. The problems faced in the usage of remote sensing data in geological application are highlighted.
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