s="" geologic="" features.="" with="" the="" development="" of="" optomechanical="" scanner,="" scientists="" began="" to="" construct="" digital="" multispectral="" images="" using="" data="" beyond="" sensitivity="" range="" visible="" light="" photography.="" these="" are="" constructed="" by="" mechanically="" aligning="" pictorial="" representations="" such="" phenomena="" as="" reflection="" waves="" outside="" spectrum:="" refraction="" radio="" waves,="" and="" daily="" changes="" in="" temperature="" areas="" on="" earth's="" surface.="" imaging="" has="" now="" become="" basic="" tool="" remote="" sensing="" from="" satellites. The advantage of digital over photographic imaging is evident: the resulting numerical data are precisely known, and digital data are not subject to the vagaries of difficult-to-control chemical processing with digital processing, it is possible to combine a large number of spectral images. The acquisition of the first multispectral digital data set from, the multispectral scanner (MSS) aboard the satellite Landsat in 1972 consequently attracted the attention of the entire geologic community. Landsat MSS data are now being applied to a variety of geologic problems that are difficult to solve by conventional methods alone. These include specific problems in mineral and energy resource exploration and the charting of glaciers and shallow seas. A more fundamental application of remote sensing is to augment conventional methods for geologic mapping of large areas. Regional maps present compositional structural and chronological information for reconstructing geologic revolution. Such reconstructions have important practical applications because the conditions under which rock units and other structural features are formed influence the occurrence of ore and petroleum deposits and affect the thickness and integrity of the geologic media in which the deposits are found. Geologic maps incorporate a large, varied body of specific field and laboratory measurements, but the maps must be interpretative because field measurements are always limited by rock exposure, accessibility and labor resources. With remote-sensing techniques, it is possible to obtain much geologic information more efficiently than it can be obtained on the ground. These techniques also facilitate overall interpretation. Since detailed geologic mapping is generally conducted in small areas, the continuity of regional features that had intermittent and variable expressions is often not recognized, but in the comprehensive views of Landsat images these continuities are apparent. However, some critical information cannot be obtained through remote sensing, and several characteristics of the Landsat MSS impose limitations on the acquisition of diagnostic data. Some of these limitations can be overcome by designing satellite systems especially for geologic purposes; but to be most effective, remote sensing data must still be combined with data from field surveys, laboratory tests, and the techniques of the earlier twentieth century.
1.Which of the following can be measured by the optomechanical scanner but not by visible light photograph?
2.Lands images differ from conventional geologic maps in that the former( ) .3.The passage provides information about all of the following topics except ( ).4.What does the author mention about “the conventional methods”?5.According to the author( ) .
'>The term "remote sensing" refers to the techniques of measurement and interpretation of phenomena from a distance. Prior to the mid-1960s the interpretation of film images was the primary means for remote sensing of the earth's geologic features. With the development of the optomechanical scanner, scientists began to construct digital multispectral images using data beyond the sensitivity range of visible light photography. These images are constructed by mechanically aligning pictorial representations of such phenomena as the reflection of light waves outside th