SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The author has identified the following significant results. Cursory examination shows that the Skylab photos alone would provide all the pictorial information needed for surveys in arid and semiarid regions according to the pattern of the Alice Springs survey (mapping at a scale of 1:1 million).
The author has identified the following significant results. A thirteen category recognition map was prepared, showing forest, water, grassland, and exposed rock types. Preliminary assessment of classification accuracies showed that water, forest, meadow, and Niobrara shale were the most accurately mapped classes. Unsatisfactory results, were obtained in an attempt to discrimate sparse forest cover over different substrates. As base elevation varied from 7,000 to 13,000 ft, with an atmospheric visibility of 48 km, no changes in water and forest recognition were observed. Granodiorite recognition accuracy decreased monotonically as base elevation increased, even though the training set location was at 10,000 ft elevation. For snow varying in base elevation from 9400 to 8420 ft, recognition decreases from 99% at the 9400 ft training set elevation to 88% at 8420 ft. Calculations of expected radiance at the ERTS sensor from snow reflectance measured at the site and from Turner model calculations of irradiance, transmission and path radiance, reveal that snow signals should not be clipped, assuming that calculations and ERTS calibration constants were correct.
Kidson's relation is briefly described. It is concluded that if a relation is found between sunspots and weather, it is likely to appear in the march of high and low pressure systems around the poles.
There are no author-identified significant results in this report.
The author has identified the following significant results. Comparisons of the imagery with aerial photography of areas of reefs and island and with 1:250,000 maps of coastlines indicate that the MSS imagery depicts detail to an extent which is satisfactory for 1:250,000 mapping. As the imagery does not have some of the disadvantages of aerial photography, the former should be valuable for mapping reefs, islands, and shoals. The water discoloration problem is significant as the discolored water appears to occur near shallow depths, so that confusion could arise through the misinterpretation of discolored water, when it exists, as shallow water.
The author has identified the following significant results. In subhumid, vegetated areas, S190B photography: (1) has a potentially operational role in detecting lineaments in 1:100,000 scale geological mapping and in major civil engineering surveys; (2) is of limited value for regional lithological mapping at 1:500,000 scale; and (3) provided much useful synoptic information and some detailed information of direct value to the mapping of nonmineral natural resources such as vegetation, land soil, and water. In arid, well exposed areas, S190B photography could be used: (1) with a limited amount of field traverses, to produce reliable 1:500,000 scale geological maps of sedimentary sequences; (2) to update superficial geology on 1:250,000 scale maps; and (3) together with the necessary field studies, to prepare landform, soil, and vegetation maps at 1:1,000,000 scale. Skylab photography was found to be more useful than LANDSAT images for small scale mapping of geology and land types, and for the revision of topographic maps at 1:100,000 scale, because of superior spatial resolution and stereoscopic coverage.
There are no author-identified significant results in this report.
The author has identified the following significant results. LANDSAT 1 and 2 imagery contrast the geology of the Cloncurry-Dobbyn and the Gregory River-Mt. Isa areas very clearly. Known major structural features and lithological units are clearly displayed while, hitherto unknown lineaments were revealed. Throughout this area, similar rock types produce similar spectral signatures, e.g. quartzites produce light signatures, iron rich rocks produce dark signatures. More geological data are discernible at the 1:50,000 scale than on the 1:250,000 scale. Ore horizons may be identified at the 1:50,000 scale, particularly where they are associated with iron rich rocks. On the level plains north of Cloncurry, distinctive spectral signatures produced by the combined reflectances of plant cover, soils, and geology, distinguish different types of superficial deposits. Existing and former channels of the Cloncurry and Williams Rivers are distinguished at the 1:50,000 scale on both the LANDSAT 1 and 2 imagery. On the Cloncurry Plains, fence lines are discernible on the 1:50,000 LANDSAT 2 imagery.
The author has identified the following significant results. Two geometric distortion tests of the same scene using different ground control identification methods have produced different estimates of the magnitude of geometric distortions of the image frame. A comparison of imagery with hydrographic charts shows that the imagery displays shoals and reefs which are close to the water surface. Such information can be used during the compilation of new maps of such regions, in the checking of existing hydrographic charts, or for navigation warning.
The author has identified the following significant results. The geometric accuracy test produced an estimate that the distortion levels on LANDSAT imagery are such that few corrections, or possibly no corrections, would be necessary in order to have the imagery satisfy accuracy specifications. It can be expected that the geometric accuracy of the low generation imagery, being used in distortion tests, in such that the distortions would cause no difficulty during the course of map preparation.
The author has identified the following significant results. The ground measurements of the reflectivity of the capeweed species shows significant variation from the pasture species measured. The variation in the capeweed signature, as a function of the flower cover indicates that the optimum time for a survey would be when the capeweed is at peak flowering.
There are no author-identified significant results in this report.
The author has identified the following significant results. Series of linears were identified on the March imagery of Lady Annie-Mt. Gordon fault zone area. The series with a WSW-ENE orientation which is normal to the major structural units and also several linears with NNW-SSE orientation appears to be particularly important. Copper mineralization is known at several localities where these linears are intersected by faults. Automated outputs using supervised methods involving the selection of training sets selected by visual recognition of spectral signatures on the color composites obtained from combinations of MSS bands 4, 5 and 7 projected through appropriate filters, were generated.
The author has identified the following significant results. Distinctive spectral signatures were found associated with areas of near surface bedrock with covered ground east of Dugald River and along the Thorntonia River valley west of Lady Annie. Linears identified in the Dugald River area on LANDSAT 2 imagery taken in March and July 1975 over the Cloncurry-Dobbyn area, displayed preferred orientation. A linear group with NE-SW orientation was identified in the Lady Annie area. In this area, the copper mineralization in the Mt. Kelly area occurs along a well marked linear with NNW/SSE direction apparent on images for March, September, and November 1975. Geobotanical anomalies provided surface expression of the copper deposits in Mt. Kelley.
The author has identified the following significant results. Contours of residual errors were depicted in east and north directions. Contours were constructed from residuals which were determined at 22 ground control points. Residuals at two control points were rejected from contour determination, as their magnitudes were not in keeping with surrounding values. Results obtained so far from depth measurement tests are only tentative. Both sucessful and unsuccessful correlations were depicted between the imagery intensities and bathymetric data. Using the results from nine profile comparisons abstracted from a scene over Torres Strait, where water was generally very clear, an empirical relationship between image intensity (1) and water depth (d) was derived: 1 = 30 - 0.75 d.
There are no author-identified significant results in this report.
There are no author-identified significant results in this report.
The present and possible future effects of pedestal tilt at the deep space tracking station are discussed. Topics include causes of the tilt, its amplitude and rate of change, and the method of measurement used. The degree of confidence in the measurements made is also examined.