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At least 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Irrigated lands assessment for water management: Technique test

A procedure for estimating irrigated land using full frame LANDSAT imagery was demonstrated. Relatively inexpensive interpretation of multidate LANDSAT photographic enlargements was used to produce a map of irrigated land in California. The LANDSAT and ground maps were then linked by regression equations to enable precise estimation of irrigated land area by county, basin, and statewide. Land irrigated at least once in California in 1979 was estimated to be 9.86 million acres, with an expected error of less than 1.75% at the 99% level of confidence. To achieve the same level of error with a ground-only sample would have required 3 to 5 times as many ground sample units statewide. A procedure for relatively inexpensive computer classification of LANDSAT digital data to irrigated land categories was also developed. This procedure is based on ratios of MSS band 7 and 5, and gave good results for several counties in the Central Valley.

Wall, S. L.↗
NASA NTRS1982

Forestry timber typing. Tanana demonstration project, Alaska ASVT

The feasibility of using LANDSAT digital data in conjunction with topographic data to delineate commercial forests by stand size and crown closure in the Tanana River basin of Alaska was tested. A modified clustering approach using two LANDSAT dates to generate an initial forest type classification was then refined with topographic data. To further demonstrate the ability of remotely sensed data in a fire protection planning framework, the timber type data were subsequently integrated with terrain information to generate a fire hazard map of the study area. This map provides valuable assistance in initial attack planning, determining equipment accessibility, and fire growth modeling. The resulting data sets were incorporated into the Alaska Department of Natural Resources geographic information system for subsequent utilization.

Morrissey, L. A.↗
NASA NTRS1981

Some considerations in low-cost image processing on a university main frame: The Penn State (ORSER) experience

The ORSER System as implemented on the Penn State University Computation Center's IBM main frame is an exceptionally useful mechanism for instructing the present and future remote sensing community in the theory and practice of automated analysis of digitized data. From its beginning, the system was used as the hands-on back-bone of a graduate level "Multispectral Remote Sensing" one-term course taught annually in the School of Forest Resources. It was also used at the end of a senior-level undergraduate "Introduction to Remote Sensing" course, and in teaching a variety of short courses, ranging in length from a few days for small groups of remote sensing consultants with specific application interests, to a 2-week course oganized by NASA for regional and urban planners who had little or no previous exposure to remote sensing. Because of its modular construction, the ORSER is suitable for all classes of remote sensing users. Although in a beginning course only 6 to 10 of the programs are generally used, the researcher has a set of about 35 programs available for his analyses.

Turner, B. J.↗
NASA NTRS1981

Oregon trails revisted

Oregon State University's Environmental Remote Sensing Applications Laboratory (ERSAL) has six full-time researchers with expertise in a variety of biological, Earth, atmospheric and computer sciences as well as image interpretation and statistical techniques. The primary emphasis of the ERSAL research and demonstration program is the development and application of remote sensing technology in operational resource management programs. LANDSAT multi-spectral, multi-date digital data and imagery are utilized in concert with high altitude NASA-acquired photography, low altitude ERSAL-acquired photography, and field observations and data to provide customized, inexpensive and useful final products. Synopses are given of 9 applications projects conducted in Oregon.

Lewis, A. J.↗
NASA NTRS1981

The pacific northwest remote sensing project

The history of a 3-year effort in Idaho, Oregon, and Washington to establish operational capabilities to analyze LANDSAT digital data and apply the results to natural resources management programs is related. Currently a number of agencies are conduct operational applications projects utilizing the data analysis facilities available and LANDSAT-derived data are being used by these agencies in their day-to-day operations. The image analysis systems and software used in each state are described and the participating state and local agencies are listed.

Hedrick, W. E.↗
NASA NTRS1982

Telemetry system

The means of telemetering digital data from a spacecraft to the Deep Space Network is addressed. Phase shift keying and uncoded quadriphase shift keying modulations are discussed along with demodulation and decoding systems. Telemetry system losses and noisy reference performance for suppressed carrier receivers are also examined.

Yuen, J. H.↗
NASA NTRS1983

LANDSAT 4 investigations of thematic mapper and multispectral scanner applications

Digital data analyses suggest the potential for TM data to provide improved land cover information with the mid-IR band being especially useful. Coefficients of variations for major land categories were greater for MSS data channels than for TM channels. Interpretation of black and white images of the six reflective TM bands indicates a strong interpreter preference for bands 5 and 7 for making distinctions in most of the classification categories that were addressed; however, a strong case can be made for a color composite containing visible, near-IR, and mid-IR spectral regions when distinguishing vegetation. A transformation from each red, green, blue color space into hue, intensity, and saturation space has potential for enhanced interpretability of TM color composite images. A perspective view transformation was demonstrated that could be useful for presently registered layers of spatial data in an oblique view format.

Lauer, D. T.↗
NASA NTRS1983

Effects of autocorrelation upon LANDSAT classification accuracy

Richmond, Virginia and Denver, Colorado were study sites in an effort to determine the effect of autocorrelation on the accuracy of a parallelopiped classifier of LANDSAT digital data. The autocorrelation was assumed to decay to insignificant levels when sampled at distances of at least ten pixels. Spectral themes developed using blocks of adjacent pixels, and using groups of pixels spaced at least 10 pixels apart were used. Effects of geometric distortions were minimized by using only pixels from the interiors of land cover sections. Accuracy was evaluated for three classes; agriculture, residential and "all other"; both type 1 and type 2 errors were evaluated by means of overall classification accuracy. All classes give comparable results. Accuracy is approximately the same in both techniques; however, the variance in accuracy is significantly higher using the themes developed from autocorrelated data. The vectors of mean spectral response were nearly identical regardless of sampling method used. The estimated variances were much larger when using autocorrelated pixels.

Craig, R. G.↗
NASA NTRS1982

Mapping urban land cover from space: Some observations for future progress

The multilevel classification system adopted by the USGS for operational mapping of land use and land cover at levels 1 and 2 is discussed and the successes and failures of mapping land cover from LANDSAT digital data are reviewed. Techniques used for image interpretation and their relationships to sensor parameters are examined. The requirements for mapping levels 2 and 3 classes are considered.

Gaydos, L.↗
NASA NTRS1982

An automated mapping satellite system (MAPSAT)

Digital data from highly stabilized stereo linear arrays are amenable to simplified processing to produce both planimetric imagery and elevation data. A satellite, called MAPSAT, including this concept was proposed to accomplish automated mapping in near real time. Image maps as large as 1:50,000 scale with contours as close as 20-m interval may be produced from MAPSAT data.

Colvocoresses, A. P.↗
NASA NTRS1982

LANDSAT imagery: Description of products available from the CSIR Satellite Remote Sensing Centre

An overview of the LANDSAT system is provided along with information to assist prospective users in establishing whether imagery for their areas of interest is available and how to obtain such imagery. Spectral bands, spatial resolution, and digital data are explained as well as worldwide reference system indexing and the identification number assigned to images. The sizes and scales of standard black and white imagery and of false color composite imagery are listed. The format is given for computer compatible tapes and standard enhanced imagery is described. Other information available to users include LANDSAT index maps, catalogs of available imagery, a schedule of overpass dates, and a list of product prices.

Source record↗
NASA NTRS1981

Landsat observations of Mount St. Helens

The eruption of Mount St. Helens on May 18, 1980, and subsequent destruction of approximately 593 square kilometers (229 square miles) of vegetation, clearly provided a unique opportunity for earth-oriented satellite remote sensing systems. Landsat, a relatively high resolution Multispectral Scanner (MSS) system, imaged Mount St. Helens both before and after its major eruption. Digital data have been used to create a damage assessment map and a change detection image. Several classes of timber damage and land cover modification have been developed. Acreages for each class have been tabulated.

Bohn, C. G.↗
NASA NTRS1983

A noninteractive procedure for land-use determination

A complete operational procedure designed for use by the U.S. Army Corps of Engineers for the determination of land-use information for hydrologic planning purposes is reported. The procedure combines photo interpretation techniques and the batch-mode computer analysis of Landsat digital data. Since the operational constraints preclude the use of dedicated, interactive image processing facilities, several novel approaches to geometric correction, classification, and data input/output were developed. The procedure is summarized, and examples of the application of the procedure to urban watersheds are described. In spite of the constraints, the procedure provides results comparable in accuracy and lower in cost than those provided by commercial services using interactive techniques.

Ford, G. E.↗
NASA NTRS1983

Two-dimensional photometry of planetary nebulae

In connection with the study of planetary nebulae, problems still exist in understanding such basic properties as three-dimensional structure, optical opacity to the central star's ionizing flux, and electron temperature and electron density variations within the nebular gas. To study these properties, two-dimensional images taken in many spectral lines are required. However, such a study presents a formidable problem in data analysis. In the present investigation, an attempt has been made to overcome the difficulties by using an imaging system which encodes the data digitally. Calibrated intensity maps could be constructed to test models of ionization structure and to produce two-dimensional maps of electron temperature and density. Both the results of a uniform-shell test and the nature of the solutions for the volume emissivity were found to support a nebular model in which the bright ring is part of a closed shell of variable density that resembles the torus proposed by Minkowski and Osterbrock (1960).

Kupferman, P. N.↗
NASA NTRS1982

Some technical considerations on the evolution of the IBIS system

In connection with work related to the use of earth-resources images, it became apparent by 1974, that certain system improvements are necessary for the efficient processing of digital data. To resolve this dilemma, Billingsley and Bryant (1975) proposed the use of image processing technology. Bryant and Zobrist (1976) reported the development of the Image Based Information System (IBIS) as a subset of an overall Video Image Communication and Retrieval (VICAR) image processing system. A description of IBIS is presented, and its employment in connection with advanced applications is discussed. It is concluded that several important lessons have been learned from the development of IBIS. The development of a flexible system such as IBIS is found to rest upon the prior development of a general purpose image processing system, such as VICAR.

Bryant, N. A.↗
NASA NTRS1981

A review of unsteady turbulent boundary-layer experiments

The essential results of a comprehensive review of existing unsteady turbulent boundary-layer experiments are presented. Different types of unsteady flow facilities are described, and the related unsteady turbulent boundary-layer experiments are cataloged and discussed. The measurements that were obtained in the various experiments are described, and a complete list of experimental results is presented. All the experiments that measured instantaneous values of velocity, turbulence intensity, or turbulent shear stress are identified, and the availability of digital data is indicated. The results of the experiments are analyzed, and several significant trends are identified. An assessment of the available data is presented, delineating gaps in the existing data, and indicating where new or extended information is needed. Guidelines for future experiments are included. Previously announced in STAR as N81-29382

Carr, L. W.↗
NASA NTRS1985

Automatic Robot Safety Shutdown System

Robot turned off if acceleration exceeds preset value. Signals from accelerometer on robot arm pass through filter and amplifier, eliminating high-frequency noise and hydraulic-pump pulsations. Data digitized and processed in computer. Unit controls other machines that perform repetitive movements, including rotary tables, tracked vehicles, conveyor lines, and elevators.

Lirette, M.↗
NASA NTRS1983

A study on airborne integrated display system and human information processing

The cognitive behavior of pilots was examined in an experiment involving mock ups of an eight display electronic attitude direction indicator for an airborne integrated display. Displays were presented in digital, analog digital, and analog format to experienced pilots. Two tests were run, one involving the speed of memorization in a single exposure and the other comprising two five second exposures spaced 30 sec apart. Errors increased with the speed of memorization. Generally, the analog information was assimilated faster than the digital data, with regard to the response speed. Information processing was quantified as 25 bits for the first five second exposure and 15 bits during the second.

Mizumoto, K.↗