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At least 1,477 records · Page 82
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Study of application of ERTS-A imagery to fracture related mine safety hazards in the coal mining industry

The author has identified the following significant results. The 70mm black and white infrared photography acquired in March 1973 at an approximate scale of 1:115,000 permits the identification of areas of mine subsidence not readily evident on other films. This is largely due to the high contrast rendition of water and land by this film and the excessive surface moisture conditions prevalent in the area at the time of photography. Subsided areas consist of shallow depressions which have impounded water. Patterns with a regularity indicative of the room and pillar configuration used in subsurface coal mining are evident.

Wier, C. E.↗
NASA NTRS1973

Fracture trends identified by ERTS-1 imagery in Utah and Nevada

The author has identified the following significant results. Structures clearly traceable through bed rock are considered most reliable. Continuity, however, is frequently traceable through ranges and across adjoining sedimentary basins where changes in drainage, erosion pattern, soil color, or vegetation suggest that the basin sediments are extremely sensitive to underlying structures. Many large and continuous trends, too smeared by erosion to be visible on the ground or from aircraft photos, become quite evident at the scale of the ERTS-1 images. The study was made with little regard for surface geology. The trends have been retraced to separate and unidirectional sets. These are now being related to surface geology, geophysical studies, volcanic and intrusive centers, and areas of mineralization.

Jensen, M. L.↗
NASA NTRS1973

Ocean water color assessment from ERTS-1 RBV and MSS imagery

The author has identified the following significant results. Photo-optical and electronic density slicing were applied to ERTS-1 E 1007-151651-4, 30 July 1972, an area in the Caribbean showing deep ocean water, and shallow areas on the Great Baham Bank ranging from 0.5 meter or less to 18 meters. The density slicing processes were adjusted to correlate water radiance to bathmetric contours shown on C and GS Chart 1112. A number of large areas corresponding to water depths of 2 meters or less, 5 to 10 meters, and 10 to about 20 meters were isolated by both processes. Where clear water and uniformly reflective bottom was found, clear of marine growths, the photo-optical and electronic image density slicing processes proved effective in delineating areas where the depth was in the order of 5 meters, plus or minus 1 meter.

Ross, D. S.↗
NASA NTRS1973

Inventory and monitoring of natural vegetation and related resources in an arid environment by the use of ERTS-1 imagery

The author has identified the following significant results. An evaluation of information content of ERTS-1 reconstituted photography in comparison with Apollo 6 and Gemini 4 photography has been accomplished for some landforms through the use of an image groupability testing procedure. Analysis of terrain feature-vegetation relationships has been completed. Ground truth data collected in the southern Arizona test site have indicated that many of the plants can be categorized as either evergreen, cool season deciduous, or warm season deciduous. Results from image groupability testing have been utilized to stratify an Apollo 6 scene and an ERTS-1 scene of the same area.

Schrumpf, B. J.↗
NASA NTRS1973

Recognition of the geologic framework of porphyry deposits on ERTS-1 imagery

The author has identified the following significant results. Photointerpretation methods have been most successfully applied in the less vegetated test sites where several previously unknown geologic features have been recognized and known ones extended. Northwest mid-Tertiary faults in the ELY, Nevada area are observed to offset north-trending ranges and abruptly terminate older Mesozoic structures. In the Ray, Arizona area the observed patterns of fault and fracture systems appear to be related to the locations of known porphyry copper deposits. In the Tanacross, Alaska area a number of regional circular features observed may represent near surface intrusions and, therefore, permissive environments for copper porphyries.

Wilson, J. C.↗
NASA NTRS1973

A photographic processing control method for ERTS imagery

Radiometric accuracy of ERTS photographic image processing is assured by the use of control targets, i.e., sensitometric strips for equipment certification and end-of-roll targets for process verification. These targets are produced by a sensitometer that is calibrated to cover the performance range parameters. Curve fitting techniques are used to collect performance data accurately, and a feedback procedure indicates malfunctioning.

Peavey, B.↗
NASA NTRS1973

Identification of winter wheat from ERTS-1 imagery

Continuing interpretation of the test area in Finney County, Kansas, has revealed that winter wheat can be successfully identified. This successful identification is based on human recognition of tonal signatures on MSS images. Several different but highly successful interpretation strategies have been employed. These strategies involve the use of both spectral and temporal inputs. Good results have been obtained from a single MSS-5 image acquired at a critical time in the crop cycle (planting). On a test sample of 54,612 acres, 89 percent of the acreage was correctly classified as wheat or non-wheat and the estimated wheat acreage (19,516 acres) was 99 percent of the actual acreage of wheat in the sample area.

Williams, D. L.↗
NASA NTRS1973

Vegetative and geologic mapping of the western Seward Peninsula, Alaska, based on ERTS-1 imagery

ERTS-1 scene 1009-22095 (Western Seward Peninsula, Alaska) has been studied, partly as a training exercise, to evaluate whether direct visual examination of individual and custom color-composite prints can provide new information on the vegetation and geology of this relatively well known area of Alaska. The vegetation analysis reveals seven major vegetation types, only four of which are described on existing vegetation maps. In addition, the ERTS analysis provides greater detail than the existing maps on the areal distribution of vegetation types. The geologic analysis demonstrates that most of the major rock units and geomorphic boundaries shown on the available geologic maps could also be identified on the ERTS data. Several major high-angle faults were observed, but the zones of thrust faults which are much less obvious.

Anderson, J. H.↗
NASA NTRS1973

Application of ERTS-1 multispectral imagery to monitoring the present episode of accelerated erosion in southern Arizona

An episode of accelerated arroyo-cutting and sheet erosion commenced about 1890 in southern Arizona, following several thousand years of generally sluggish erosion. For a 17,000-square-mile study area, ERTS-1 images, supplemented by ultrahigh-altitude (U-2 and RB-57) airphotos, are proving effective for producing the first comprehensive maps showing the distribution and seriousness of the post-1890 erosion features, for monitoring new erosion changes, and for assessing the effectiveness of ameliorative measures. Such data are essential for understanding and controlling the accelerated erosion, a key environmental problem in this region.

Morrison, R. B.↗