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At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Landsat thematic mapper (TM) soil variability analysis over Webster County, Iowa

Thematic mapper simulator (TMS) data acquired June 7, June 23, and July 31, 1982, and Landsat thematic mapper (TM) data acquired August 2, September 3, and October 21, 1982, over Webster County, Iowa, were examined for within-field soil effects on corn and soybean spectral signatures. It was found that patterns displayed on various computer-generated map products were in close agreement with the detailed soil survey of the area. The difference in spectral values appears to be due to a combination of subtle soil properties and crop growth patterns resulting from the different soil properties. Bands 4 (0.76-.90 micron), 5 (1.55-1.75 micron), and 7 (2.08-2.35 micron) were found to be responding to the within-field soil variability even with increasing ground cover. While these results are preliminary, they do indicate that the soil influence on the vegetation is being detected by TM and should provide improved information relating to crop and soil properties.

Thompson, D. R.↗
NASA NTRS1983

Landsat-4 thematic mapper (TM) for cold environments

Landsat-4 was launched into a near-polar, sun-synchronous orbit on July 16, 1982. It is the largest and most complex of NASA's earth resources satellites. Landsat-4's instrument payload includes two remote sensors. The Multispectral Scanner Subsystem (MSS) is an electro-optical scanning radiometer with four spectral bands in the visible and near infrared, which was also carried aboard Landsats 1, 2, and 3. The second sensor, the Thematic Mapper (TM), represents a more advanced remote sensing instrument than the MSS. It uses a scanning mirror assembly to collect data from a 15.4 deg angle on both forward and reverse scans. It is pointed out that the improved spatial, spectral, and radiometric characteristics of TM have significant implications for satellite remote sensing in cold environments. The expected improvements are discussed, giving attention to snow, ice, water, soil, and land cover.

Gervin, J. C.↗
NASA NTRS1985

A TM Tasseled Cap equivalent transformation for reflectance factor data

A transformation of TM-waveband reflectance-factor data which provides features related as directly as possible to the corresponding TM Tasseled Cap brightness, greennes, and wetness features is presented. The reflectance factor transformation is based on spectrometer data integrated over the prelaunch composite-detector response functions of the Landsat-4 Thematic Mapper. A description, in general terms, of the approach for adjusting the transformation matrix to other types of reflectance factor data (different instrument or band response) is given.

Crist, E. P.↗
NASA NTRS1983

LANDSAT-4 TM image data quality analysis for energy-related applications

LANDSAT-4 Thematic Mapper (TM) data performance and utility characteristics from an energy research and technology perspective is evaluated. The program focuses on evaluating applicational implications of using such data, in combination with other digital data, for current and future energy research and technology activities. Prime interest is in using TM data for siting, developing and operating federal energy facilities. Secondary interests involve the use of such data for resource exploration, environmental monitoring and basic scientific initiatives such as in support of the Continental Scientific Drilling Program.

Wukelic, G. E.↗
NASA NTRS1985

Characterization of LANDSAT-4 MSS and TM digital image data

The launch of LANDSAT-4 in July 1982 represents a continuation in the remote sensing of earth resources. The 80-m spatial resolution provided by the Multispectral Scanner (MSS) on board the satellite is fine enough to resolve many natural features and land-use details in both rural and urban settings. The second sensor of the spacecraft, the Thematic Mapper (TM), introduce a new era of sensing with refined spatial resolution (30 m) and expanded spectral coverage (7 bands). This paper describes results from engineering studies of the characteristics of digital image data from the two LANDSAT-4 sensors are described. These studies form a part of the LANDSAT-4 Image Data Quality Analysis program (LIDQA). The image data were generally found to be of high quality and the TM provided several improvements over the MSS, in its spatial and spectral characteristics.

Malila, W. A.↗
NASA NTRS1985

Information theoretic comparisons of original and transformed data from Landsat MSS and TM

The dispersion and concentration of signal values in transformed data from the Landsat-4 MSS and TM instruments are analyzed using a communications theory approach. The definition of entropy of Shannon was used to quantify information, and the concept of mutual information was employed to develop a measure of information contained in several subsets of variables. Several comparisons of information content are made on the basis of the information content measure, including: system design capacities; data volume occupied by agricultural data; and the information content of original bands and Tasseled Cap variables. A method for analyzing noise effects in MSS and TM data is proposed.

Malila, W. A.↗
NASA NTRS1986

Lithologic discrimination of volcanic and sedimentary rocks by spectral examination of Landsat TM data from the Puma, Central Andes Mountains

The Central Andes are widely used as a modern example of noncollisional mountain-building processes. The Puna is a high plateau in the Chilean and Argentine Central Andes extending southward from the altiplano of Bolivia and Peru. Young tectonic and volcanic features are well exposed on the surface of the arid Puna, making them prime targets for the application of high-resolution space imagery such as Shuttle Imaging Radar B and Landsat Thematic Mapper (TM). Two TM scene quadrants from this area are analyzed using interactive color image processing, examination, and automated classification algorithms. The large volumes of these high-resolution datasets require significantly different techniques than have been used previously for the interpretation of Landsat MSS data. Preliminary results include the determination of the radiance spectra of several volcanic and sedimentary rock units and the use of the spectra for automated classification. Structural interpretations have revealed several previously unknown folds in late Tertiary strata, and key zones have been targeted to be investigated in the field. The synoptic view of space imagery is already filling a critical gap between low-resolution geophysical data and traditional geologic field mapping in the reconnaissance study of poorly mapped mountain frontiers such as the Puna.

Fielding, E. J.↗
NASA NTRS1985

Enhanced rock discrimination using Landsat-5 Thematic Mapper (TM) data

The application of TM data to rock discrimination is discussed. Sixteen specific terrains derived from geologic maps are examined on TM images of the Arabian shield obtained on Apr. 14, 1984; visual enhancement procedures are applied to the images. The rock types observed in the test site are described; the major sedimentary formations in the test area are laterite and sandstone. The data reveal that the layered rocks in the outcrop consist of a variety of metamorphosed volcanics, metamorphosed sediments, and amphibolite, and the intrusive complex is composed of several classes of mafic and acidic rocks.

Blodget, H. W.↗
NASA NTRS1987

An assessment of Landsat MSS and TM data for urban and near-urban land-cover digital classification

The information content of Landsat TM and MSS data was examined to assess the ability to digitally differentiate urban and near-urban land covers around Miami, FL. This examination included comparisons of unsupervised signature extractions for various cover types, training site statistics for intraclass and interclass separability, and band and band combination selection from an 11-band multisensor data set. The principal analytical tool used in this study was transformed divergence calculations. The TM digital data are typically more useful than the MSS data in the homogeneous near-urban land-covers and less useful in the heterogeneous urban areas.

Haack, Barry↗
NASA NTRS1987

Analysis of Eocene depositional environments - Preliminary TM and TIMS results, Wind River Basin, Wyoming

Both Landsat TM and aircraft Thermal IR Multispectral Scanner (TIMS) data have been used to map the lithofacies of the Wind River Basin's Eocene physical and biological environments. Preliminary analyses of these data have furnished maps of a fault contact boundary and a complex network of fluvial ribbon channel sandstones. The synoptic view thereby emerging for Eocene fluvial facies clarifies the relationships of ribbon channel sandstones to fossil-bearing overbank/floodplain facies and certain peleosols. The utility of TM and TIMS data is thereby demonstrated.

Stucky, Richard K.↗
NASA NTRS1987

Stereocorrelation of Landsat TM images

A digital elevation model (DEM) developed from Landsat TM images of a rugged terrain area in north Georgia by automated stereocorrelation techniques yielded an rms error (z), RMSE(z), value of + or - 42 m. Based on the B/H ratio of 0.18 for the Landsat data, this Z-error corresponds to a planimetric correlation accuracy of about + or - 0.3 pixels, confirming that precise correlation can be achieved with operational satellite data. Contours at a 100-m interval interpolated from the DEM show a deviation of + or - 33 m from reference contours obtained from existing 1:24,000-scale maps. The 28.5-m pixel resolution and the weak B/H ratio impose limitations on the accuracy that can be achieved with Landsat TM data. However, it is anticipated that RMSE(z) values of + or - 10 m or less can be achieved with SPOT-1 panchromatic stereo images of 10-m resolution recorded at B/H ratios of 0.5 to 1.0. DEMs generated by stereocorrelation techniques can be used to create orthoimages, perspective views, and topographic map products.

Ehlers, Manfred↗
NASA NTRS1987

An integrtated approach to the use of Landsat TM data for gold exploration in west central Nevada

This paper represents an integration of several Landsat TM image processing techniques with other data to discriminate the lithologies and associated areas of hydrothermal alteration in the vicinity of the Paradise Peak gold mine in west central Nevada. A microprocessor-based image processing system and an IDIMS system were used to analyze data from a 512 X 512 window of a Landsat-5 TM scene collected on June 30, 1984. Image processing techniques included simple band composites, band ratio composites, principal components composites, and baseline-based composites. These techniques were chosen based on their ability to discriminate the spectral characteristics of the products of hydrothermal alteration as well as of the associated regional lithologies. The simple band composite, ratio composite, two principal components composites, and the baseline-based composites separately can define the principal areas of alteration. Combined, they provide a very powerful exploration tool.

Mouat, D. A.↗
NASA NTRS1988

Cartographic feature extraction with integrated SIR-B and Landsat TM images

A digital cartographic multisensor image database of excellent geometry and improved resolution was created by registering SIR-B images to a rectified Landsat TM reference image and applying intensity-hue-saturation enhancement techniques. When evaluated against geodetic control, RMSE(XY) values of approximately + or - 20 m were noted for the composite SIR-B/TM images. The completeness of cartographic features extracted from the composite images exceeded those obtained from separate SIR-B and TM image data sets by approximately 10 and 25 percent, respectively, indicating that the composite images may prove suitable for planimetric mapping at a scale of 1:100,000 or smaller. At present, the most effective method for extracting cartographic information involves digitizing features directly from the image processing display screen.

Welch, R.↗
NASA NTRS1990

Seasonal LAI in slash pine estimated with LANDSAT TM

The leaf area index (LAI, total area of leaves per unit area of ground) of most forest canopies varies throughout the year, yet for logistical reasons it is difficult to estimate anything more detailed than a seasonal maximum LAI. To determine if remotely sensed data can be used to estimate LAI seasonally, field measurements of LAI were compared to normalized difference vegetation index (NDVI) values derived using LANDSAT Thematic Mapper (TM) data, for 16 fertilized and control slash pine plots on 3 dates. Linear relationships existed between NDVI and LAI with R(sup 2) values of 0.35, 0.75, and 0.86 for February 1988, September 1988, and March, 1989, respectively. This is the first reported study in which NDVI is related to forest LAI recorded during the month of sensor overpass. Predictive relationships based on data from eight of the plots were used to estimate the LAI of the other eight plots with a root-mean-square error of 0.74 LAI, which is 15.6 percent of the mean LAI. This demonstrates the potential use of LANDSAT TM data for studying seasonal dynamics in forest canopies.

Curran, Paul J.↗
NASA NTRS1992

Tm,Ho:YAG laser with tunable range of 2.08-2.12 microns and its applications to spectroscopy

In recent advanced lasers, 2 micron solid-state lasers such as Tm:YAG and Ho:YAG lasers are very attractive for laser radar remote sensing technologies because of eye safety, realizations of all solid-state laser pumped by diode laser and smaller dimension, tunability of lasing wavelength, possibility of coherent detection, etc. Featuring these advantages, 2 micron lasers have been candidated as laser transmitters for use in water vapor Differential Absorption Lidar (DIAL), laser altimeter, Doppler wind sensor, Mie lidar, etc. Characterization of a tunable Cr, Tm, Ho:YAG laser and its applications to spectroscopy concerning absorption and reflectance are reported.

Asai, Kazuhiro↗
NASA NTRS1991

Improving classification of crop residues using digital land ownership data and Landsat TM imagery

Plant residue on the surface of cultivated soils in Miami County, Indiana is analyzed in terms of quantity and type with Landsat TM data to generate information for a conservation program for agricultural soil. The Landsat data are enhanced with land-ownership data in a geographic information system to facilitate classification with maximum-likelihood, minimum-distance, and neural-network classifiers. The most effective classifications resulted from the use of the neural network on the enhanced TM data.

Zhuang, Xin↗
NASA NTRS1992

Evaluation of natural and man-made features using Landsat TM data

Landsat-5 TM data of a subscene of Washington, D.C. are utilized to distinguish man-made and natural surfaces through analysis of their spectral response. A quantitative measure of the separability and thus the ability to separate different surface features is calculated utilizing the quantity known as divergence, a measure of the dissimilarity between two distributions. The thermal band, TM band 6 (10.4-12.5 microns), was shown to improve the separability when replacing a visible band, but decreased the separability when included with the middle IR bands.

Ormsby, J. P.↗
NASA NTRS1992

Seasonal LAI in slash pine estimated with Landsat TM

The leaf area index (LAI, total area of leaves per unit area of ground) of most forest canopies varies throughout the year, yet for logistical reasons it is difficult to estimate anything more detailed than a seasonal maximum LAI. To determine if remotely sensed data can be used to estimate LAI seasonally, field measurements of LAI were compared to normalized difference vegetation index (NDVI) values derived using Lnandsat Thematic Mapper (TM) data, for 16 fertilized and control slash pine plots on 3 dates. Linear relationships existed between NDVI and LAI with R (sup 2) values of 0.35, 0.75, and 0.86 for February 1988, September 1988, and March, 1989, respectively. This is the first reported study in which NDVI is related to forest LAI recorded during the month of sensor overpass. Predictive relationships based on data from eight of the plots were used to estimate the LAI of the other eight plots with a root-mean-square error of 0.74 LAI, which is 15.6 percent of the mean LAI. This demonstrates the potential use of Landsat TM data for studying seasonal dynamics in forest canopies.

Curran, Paul J.↗