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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

A catalog system for remote-sensing data

The Practical System for Cataloging, Indexing, and Retrieval of Remote Sensing Data developed by the Interdisciplinary Remote Sensing Group at the University of Wisconsin consists of a card catalog, a site-index-map, a site-index-file, an industry-index-file, and a project-index-file. The system is designed for retrieval of remote-sensing data which include imagery, magnetic tapes, flight logs, maps, ground-truth reports, and research reports containing raw data. It can be operated by conventional library methods, but provision has been made for digitizing the system for computer retrieval.

Singh, R. S.↗
NASA NTRS1974

A study to explore the use of orbital remote sensing to determine native arid plant distribution

The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate.

Mcginnies, W. G.↗
NASA NTRS1972

Interaction of marine geodesy, satellite technology and ocean physics

The possible applications of satellite technology in marine geodesy and geodetic related ocean physics were investigated. Four major problems were identified in the areas of geodesy and ocean physics: (1) geodetic positioning and control establishment; (2) sea surface topography and geoid determination; (3) geodetic applications to ocean physics; and (4) ground truth establishment. It was found that satellite technology can play a major role in their solution. For solution of the first problem, the use of satellite geodetic techniques, such as Doppler and C-band radar ranging, is demonstrated to fix the three-dimensional coordinates of marine geodetic control if multi-satellite passes are used. The second problem is shown to require the use of satellite altimetry, along with accurate knowledge of ocean-dynamics parameters such as sea state, ocean tides, and mean sea level. The use of both conventional and advanced satellite techniques appeared to be necessary to solve the third and fourth problems.

Mourad, A. G.↗
NASA NTRS1972

Bistatic radar sea state monitoring

Bistatic radar techniques were examined for remote measurement of the two-dimensional surface wave height spectrum of the ocean. One technique operates at high frequencies (HF), 3-30 MHz, and the other at ultrahigh frequencies (UHF), approximately 1 GHz. Only a preliminary theoretical examination of the UHF technique was performed; however the principle underlying the HF technique was demonstrated experimentally with results indicating that an HF bistatic system using a surface transmitter and an orbital receiver would be capable of measuring the two-dimensional wave height spectrum in the vicinity of the transmitter. An HF bistatic system could also be used with an airborne receiver for ground truth ocean wave spectrum measurements. Preliminary system requirements and hardware configurations are discussed for both an orbital system and an aircraft verification experiment.

Ruck, G. T.↗
NASA NTRS1975

Interpretation of remote sensing data in the Bayou Lafourche Delta of south Louisiana

Initial efforts were directed toward a comprehensive ground truth program for the Bayou Lafourche Delta. The impact of transportation systems on the marsh environment, impounded marsh areas, proposed jetty systems at Belle Pass, Louisiana, and erosion and sediment transport in the southwestern canal, Lafourche Parish, Louisiana are studied. The use of color IR imagery for a vegetation study of spoil banks in the Bayou Lafourche Region is also discussed.

Whitehurst, C. A.↗
NASA NTRS1975

Pressure contact sounding data for NASA's Atmospheric Variability Experiment (AVE 2)

The basic rawinsonde data are described at each pressure contact from the surface to sounding termination for the 54 stations participating in the AVE 2 pilot experiment. Soundings were taken at three-hour intervals from stations within the United States east of about 105 degrees west longitude. Methods of data reduction and estimates of data accuracy are discussed. Examples of the data records produced are shown. The AVE 2 pilot experiment was conducted as part of NASA's program to better understand and establish the extent of applications for meteorological satellite sensor data through correlative ground truth experiments and to provide basic experimental data for use in studies of atmospheric scales-of-motion interrelationships.

Fuelberg, H. E.↗
NASA NTRS1975

Methods of extending signatures and training without ground information

Methods of performing signature extension, using LANDSAT-1 data, are explored. The emphasis is on improving the performance and cost-effectiveness of large area wheat surveys. Two methods were developed: ASC, and MASC. Two methods, Ratio, and RADIFF, previously used with aircraft data were adapted to and tested on LANDSAT-1 data. An investigation into the sources and nature of between scene data variations was included. Initial investigations into the selection of training fields without in situ ground truth were undertaken.

Henderson, R. G.↗
NASA NTRS1975

Preliminary data for the 20 May 1974, simultaneous evaluation of remote sensors experiment

Several remote sensors were simultaneously used to collect data over the tidal James River from Hopewell to Norfolk, Virginia. Sensors evaluated included the Multichannel-Ocean Color Sensor, multispectral scanners, and multispectral photography. Ground truth measurements and remotely sensed data are given. Preliminary analysis indicates that suspended sediment and concentrated industrial effluent are observable from all sensors.

Johnson, R. W.↗
NASA NTRS1975

Earth resources evaluation for New Mexico by LANDSAT-2

The author has identified the following significant results. A cost effective technique is considered for measuring and monitoring surface area fluctuations in lake size in southeastern New Mexico over a two year period. The lakes are shallow, and therefore a small volume increase results in a noticeable increase in surface area on the LANDSAT imagery. Lake sizes are measured on an I(2)S Digicol viewer. Water from potash mining operations is being pumped into some of these lakes and the input volume is documented. Using water input and surface contour as well as direct lake level measurements as ground truth as well as the LANDSAT images, calculations may be possible regarding how much additional industrial water can be added to these lakes without the occurrence of saline see page into the major river system.

Vonderlinden, K.↗
NASA NTRS1975

Multidisciplinary analysis of Skylab photography for highway engineering purposes

The author has identified the following significant results. The greatly increased resolution of ground features by Skylab as compared with LANDSAT is considered to be best in the S190B high resolution film, followed by S190A camera stations 4, 5, and 6 respectfully. Results of the study of vegetation damage sites using data derived from S190A film were disappointing. The major cause of detection problems is the graininess of the CIR film. Good results were achieved for the hydrology-land use study. Both camera systems gave better agreement with the ground truth than did LANDSAT imagery. Surficial geology and glacial landform areas were clearly visible in single scenes. Several previously unmapped or unknown features were detected, especially in eastern coastal Maine.

Stoeckeler, E. G.↗
NASA NTRS1974

Application of earth resources technology satellite data to urban and regional planning: Test site, County of Los Angeles

The author has identified the following significant results. The County of Los Angeles photointerpreted ERTS film products to define problems of interest, coordinated ground truth over the complex test site including interfaces with secondary users as well as participated in on-line analyses of the GE multispectral information extraction systems. Interactive machine analyses were carried out, developing techniques and procedures as well as evaluating the outputs for community and regional planning. Extensive aircraft underflight coverage was provided that was valuable both in inputs preparation and outputs evaluation of the machine-aided analyses. One of the nonstandard ERTS images led to the discovery of a major new fault lineament on the northern slope of the Santa Monica Mountains.

Raje, S.↗
NASA NTRS1975

Study to develop improved spacecraft snow survey methods using Skylab/EREP data

The author has identified the following significant results. Of the four black and white S190A camera stations, snowcover is best defined in the two visible spectral bands, due in part to their better resolution. The overall extent of the snow can be mapped more precisely, and the snow within shadow areas is better defined in the visible bands. Of the two S190A color products, the aerial color photography is the better. Because of the contrast in color between snow and snow-free terrain and the better resolution, this product is concluded to be the best overall of the six camera stations for detecting and mapping snow. Overlapping frames permit stereo viewing, which aids in distinguishing clouds from the underlying snow. Because of the greater spatial resolution of the S190B earth terrain camera, areal snow extent can be mapped in greater detail than from the S190A photographs. The snow line elevation measured from the S190A and S190B photographs is reasonable compared to the meager ground truth data available.

Barnes, J. C.↗
NASA NTRS1975

Remote profiling of lake ice using an S-band short pulse radar aboard an all-terrain vehicle

An airborne short-pulse radar system to measure ice thickness was designed. The system supported an effort to develop an all-weather Great Lakes Ice Information System to aid in extending the winter navigation season. Experimental studies into the accuracy and limitations of the system are described. A low power version was operated from an all-terrain vehicle on the Straits of Mackinac during March 1975. The vehicle allowed rapid surveying of large areas and eliminated the ambiguity in location between the radar system and the ground truth ice auger team. It was also possible to the effects of snow cover, surface melt water, pressure ridging, and ice type upon the accuracy of the system. Over 25 sites were explored which had ice thicknesses from 29 to 60 cm. The maximum radar overestimate was 9.8 percent, while the maximum underestimate was 6.6 percent. The average error of the 25 measurements was 0.1 percent.

Cooper, D. W.↗
NASA NTRS1975

Remotely sensing wheat maturation with radar

The scattering properties of wheat were studied in the 8-18 GHz band as a function of frequency, polarization, incidence angle, and crop maturity. Supporting ground truth was collected at the time of measurement. The data indicate that the radar backscattering coefficient is sensitive to both radar system parameters and crop characteristics particularly at incidence angles near nadir. Linear regression analyses of the radar backscattering coefficient on both time and plant moisture content result in rather good correlation. Furthermore, by calculating the average time rate of change of the radar backscattering coefficient it is found that it undergoes rapid variations shortly before and after the wheat is harvested. Both of these analyses suggest methods for estimating wheat maturity and for monitoring the progress of harvest.

Bush, T. F.↗
NASA NTRS1975

A method for estimating proportions

A proportion estimation procedure is presented which requires only on set of ground truth data for determining the error matrix. The error matrix is then used to determine an unbiased estimate. The error matrix is shown to be directly related to the probability of misclassifications, and is more diagonally dominant with the increase in the number of passes used.

Guseman, L. F., Jr.↗
NASA NTRS1974

The detection by ERTS-1 of wind-induced ocean surface features in the lee of the Antilles Islands

Photographic data received from the ERTS-1 satellite over the Lesser Antilles Islands show distinct ocean features on the leeward side of each island. Attempts to relate these features to ocean eddy formations with the aid of ground truth data proved unsuccessful. However, surface and upper air wind data indicate a good correlation with the size, shape, and downwind extent of the ocean features. Studies to date indicate strongly that these features result from horizontal differences in a sea surface roughness due to the wind-shadow effect of the islands. The results suggest that horizontal variations in the reflectance of the sea surface will make remote sensing of the ocean mixed layer more difficult than previously anticipated. The surface reflection seems to be large enough to mask the smaller variations in backscattered energy from the mixed layer. Efforts to limit the effect of surface reflectance by photographic differencing of two multi-spectral scanner bands were unsuccessful.

Cram, R.↗
NASA NTRS1974

Determination of the aerosol content in the atmosphere from ERTS-1 data

The ERTS-1 satellite offered the opportunity of determining the feasibility of monitoring the atmospheric aerosol optical thickness on a global basis, as suggested by theoretical studies, which showed relationships between the upwelling earth-atmosphere radiance and the aerosol optical thickness, and between contrast and the aerosol optical thickness. These relationships were investigated at two test sites, using the multispectral scanner (MSS) radiance data, with ground-truth observations of the aerosol optical thickness being made with a Volz photometer at the time of the satellite overpasses. The results indicate that the MSS channels, 4, 5, and 6, centered at 0.55, 0.65, and 0.75 micron have comparable sensitivity, and that the optical thickness can be determined to within plus or minus 10% with the assumed measurement errors of the MSS.

Griggs, M.↗
NASA NTRS1974

Remote detection of soil surface moisture

Polarimetric data concerning soil surface moisture were obtained during a series of flights over the Imperial Valley, California, and Phoenix, Arizona, during March 1972. A polarimeter was installed in NASA's Convair-990 aircraft, Galileo, above a window in the floor of the aft cargo compartment in such a manner that it could view from 42 deg ahead of, to 42 deg to the rear of the nadir. It had a 3 deg field of view and a 10 nm bandwidth centered at 641 nm. The moisture content of the solid surface for fields viewed by the polarimeter was measured by determining the angle through which the light had been scattered by the soil and by observing the degree of polarization of this light produced during its interaction with the soil. The polarimeter measures this degree of polarization in terms of Stokes parameters. Ground-truth samples of soil were obtained at several depths along the flight path.

Stockhoff, E. H.↗