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At least 271 records · Page 15
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NASA NTRS1983

Thematic mapper image quality - Preliminary results

Based on images analyzed so far, the band to band registration accuracy of the thematic mapper is very good. For bands within the same focal plane, the mean misregistrations are well within the specification, 0.2 pixels. For bands between the cooled and uncooled focal planes, there is a consistent mean misregistration of 0.5 pixels along-scan and 0.2-0.3 pixels across-scan. It exceeds the permitted 0.3 pixels for registration of bands between focal planes. If the mean misregistrations were removed by the data processing software, an analysis of the standard deviation of the misregistration indicates all band combinations would meet the registration specifications except for those including the thermal band. Analysis of the periodic noise in one image indicates a noise component in band 1 with a spatial frequency equivalent to 3.2 pixels in the along-scan direction.

Wrigley, R. C.↗
NASA NTRS1983

Evaluation of Landsat Thematic Mapper for vegetated alluvium soils information

Landsat Thematic Mapper data acquired over Mississippi County, Arkansas, on August 22, 1982, were evaluated whether TM provides information that could be used for soil association maps and if soil properties (variability within vegetated fields) can be detected with the new bands on TM. It was found that TM data - especially the mid-IR and thermal bands - show the capability for separating vegetated soil landscapes on a broad basis. Analysis at the field level with a crop growing indicates that TM, with its additional and narrower bands and improved spatial resolution is influenced by within-field variability due to soils.

Thompson, D. R.↗
NASA NTRS1983

Feature selection and information content of thematic mapper simulator data for a forested environment

Feature selection and the information content of Thematic Mapper Simulator (TMS) data are investigated for a forested region in northern Idaho. The optimal TMS channels for forest structural characteristics are determined, and the capability of TMS data to describe the structural variability within a forest stand is evaluated. The comparative performance of TMS and MSS data to discriminate forest structural factors using per-pixel maximum likelihood classification is examined, and four optimal TMS channels are classified in order to ascertain if the full complement of TM channels provide higher accuracies than the four optimal ones.

Spanner, M. A.↗
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 NTRS1983

Thematic mapper data analysis

The geological applications of remote sensing technology are discussed, with emphasis given to the analysis of data from the Thematic Mapper (TM) instrument onboard the Landsat 4 satellite. The flight history and design characteristics of the Landsat 4/TM are reviewed, and some difficulties endountered in the interpretation of raw TM data are discussed, including: the volume of data; residual noise; detector-to-detector striping; and spatial misregistration between measurements. Preliminary results of several geological, lithological, geobotanical mapping experiments are presented as examples of the geological applications of the TM, and some areas for improving the guality of TM imagery are identified.

Settle, M.↗
NASA NTRS1985

Application of Thematic Mapper data to corn and soybean development stage estimation

A model, utilizing direct relationship between remotely sensed spectral data and the development stage of both corn and soybeans has been proposed and published previously (Badhwar and Henderson, 1981; and Henderson and Badhwar, 1984). This model was developed using data acquired by instruments mounted on trucks over field plots of corn and soybeans as well as satellite data from Landsat. In all cases, the data was analyzed in the spectral bands equivalent to the four bands of Landsat multispectral scanner (MSS). In this study the same model has been applied to corn and soybeans using Landsat-4 Thematic Mapper (TM) data combined with simulated TM data to provide a multitemporal data set in TM band intervals. All data (five total acquisitions) were acquired over a test site in Webster County, Iowa from June to October 1982. The use of TM data for determining development state is as accurate as with Landsat MSS and field plot data in MSS bands. The maximum deviation of 0.6 development stage for corn and 0.8 development stage for soybeans is well within the uncertainty with which a field can be estimated with procedures used by observers on the ground in 1982.

Badhwar, G. D.↗
NASA NTRS1984

Resolution estimation for the Landsat-4 Thematic Mapper

Satellite-based multispectral imaging systems have been in operation since 1972 and the latest in the Landsat series of sensors was launched in July 1982. One system parameter of interest is resolution and this paper discusses experiments to determine the actual overall resolution after launch. Experimental results for the spatial resolution estimation of bands four and five of the Landsat-D Thematic Mapper are presented here.

Mcgillem, C. D.↗
NASA NTRS1984

Landsat 4 and 5 status and results from Thematic Mapper data analyses

Landsat-1, 2, and 3 have functioned successfully well beyond their design lifetimes of one year and provided a very sizable collection of data. On July 16, 1982 with the successful launch of Landsat-4, a second generation of Landsat satellites was introduced. Landsat-4 continues to make available the observational services which had been provided by the Multispectral Scanner (MSS) on Landsats 1-3. In addition, the new satellite is provided with an improved observational capability which is based on a utilization of the Thematic Mapper (TM). The system status (March 1984) of Landsat-4 is considered along with an evaluation of the MSS, and a description of the design and performance of the TM. Attention is also given to the satellite Landsat-5, which was launched successfully on March 1, 1984, taking into account design modifications leading to improved performance and some scenes provided by the new spacecraft.

Salomonson, V. V.↗
NASA NTRS1984

The utility of Thematic Mapper sensor characteristics for surface mine monitoring

The employment of Landsat Multispectral Scanner (MSS) data for surface coal mine inventory and inspection applications has been extensively investigated. However, in spite of encouraging research results, MSS data have not gained wide acceptance for surface mine monitoring operations. This situation is partly related to MSS spatial resolution (80 m), which is considered insufficient for detailed surface mine inspection. The Thematic Mapper (TM) employed on the Landsat-4 and 5 satellites provides an improved resolution (30 m) and other refinements which are expected to enhance the usefulness of TM data relative to MSS data. The present paper reports research which was conducted to assess the usefulness of actual TM data and to quantitatively evaluate the contribution of individual sensor characteristics to data utility for surface mine monitoring. The obtained results demonstrate that the TM spatial resolution can be of immediate benefit for certain applications such as surface mine monitoring.

Irons, J. R.↗
NASA NTRS1984

Reflectance measurements from Landsat Thematic Mapper over rugged terrain

Spectral albedo measurements from the Landsat-4/5 Thematic Mapper require that spacecraft upwelling radiances be corrected for atmospheric absorption and scattering and for local surface illumination. A two-stream model is developed, with a lower boundary condition that varies with incidence angle. TM data must be registered to digital terrain data. Reflectance from points in shadows can be used to estimate optical depth. The primary application here is determination of the spectral albedo of snow. The TM is better-suited for this purpose than the MSS because of its larger dynamic range.

Dozier, J.↗
NASA NTRS1984

Evaluation of atmospheric particulate concentrations derived from analysis of ratio Thematic Mapper data

An approach for atmospheric particulate concentration evaluation above urban areas using ratio Thematic Mapper (TM) data is discussed. October 25, 1982 TM data over Chicago, IL are analyzed using TM band ratios of 1/2, 1/3, 1/4, 1/5, and 1/6 and particulate concentration estimates derived from TM ratios are tested over low reflective turbid water sites and highly reflective concrete highways. From analysis of the data it is evident that for water, the pattern of increasing particulate concentration is associated with decreasing ratio values in all band combinations used. Over concrete features, the TM band 1/4 ratio values follow the predicted pattern, while the TM band 1/6 has ratios which are reversed from anticipated values.

Carnahan, W. H.↗
NASA NTRS1984

Registering Thematic Mapper imagery to digital elevation models

The problems encountered when attempting to register Landsat Thematic Mapper (TM) data to U.S. geological survey digital elevation models (DEMs) are examined. It is shown that TM and DEM data are not available in the same map projection, necessitating geometric transformation of one of the data type, that the TM data are not accurately located in their nominal projection, and that TM data have higher resolution than most DEM data, but oversampling the DEM data to TM resolution introduces systematic noise. Further work needed in this area is discussed.

Frew, J.↗
NASA NTRS1985

Preliminary spectral and geologic analysis of Landsat-4 Thematic Mapper data, Wind River Basin area, Wyoming

A Landsat-4 Thematic Mapper (TM) image of the Wind River Basin area in Wyoming is currently under analysis for stratigraphic and structural mapping and for assessment of spectral and spatial characteristics using visible, near infrared, and short wavelength infrared bands. To estimate the equivalent Lambertian surface reflectance, TM radiance data were calibrated to remove atmospheric and instrumental effects. Reflectance measurements for homogeneous natural and cultural targets were acquired about one year after data acquisition. Calibration data obtained during the analysis were used to calculate new gains and offsets to improve scanner response for earth science applications. It is shown that the principal component images calculated from the TM data were the result of linear transformations of ground reflectance. In images prepared from this transform, the separation of spectral classes was independent of systematic atmospheric and instrumental factors. Several examples of the processed images are provided.

Conel, J. E.↗
NASA NTRS1985

Evaluation of Thematic Mapper data for mapping forest, agricultural and soil resources

Color composite TM film products which include TM5, TM4, and a visible band (TM1, TM2, or TM3) are superior to composites which exclude TM4 for discriminating most forest and agricultural cover types and estimating area proportions for inventory and sampling purposes. Clustering a subset of TM data results in a spectral class map which groups diverse forest cover types into spectrally and ecologically similar areas suitable for use as a stratification base in traditional forest inventory practices. Analysis of simulated Thematic Mapper data indicate that the location and number of TM spectral bands are suitable for detecting differences in major soil properties and characterizing soil spectral curve form and magnitude.

Degloria, S.↗
NASA NTRS1985

Comparative evaluations of the geodetic accuracy and cartographic potential of Landsat-4 and Landsat-5 Thematic Mapper image data

A Landsat Image Data Quality Analysis (LIDQA) Program is conducted by NASA. One part of this program forms studies which are being performed with the objective to evaluate the geometric fidelity of Landsat-4 and Landsat-5 Thematic Mapper (TM) data in computer tape (CCT-pt) formats. It is pointed out that the Landsat-4 and Landsat-5 systems provide image data of significantly better geometric fidelity than were obtained from the earlier Landsat missions. Attention is given to the factors which influence the geometric fidelity of the Landsat TM data, the study areas and data sets, the rectification procedures, the rectification of Landsat-4 TM data and comparisons of the Scrounge and the TM Image Processing System (TIPS), the rectification of system and scene corrected Landsat-5 data processed on TIPS, and the cartographic potential of TM data.

Welch, R.↗
NASA NTRS1985

Interpretation of Landsat-4 Thematic Mapper and Multispectral Scanner data for forest surveys

Landsat-4 Thematic Mapper (TM) and Multispectral Scanner (MSS) data were evaluated by interpreting film and digital products and statistical data for selected forest cover types in California. Significant results were: (1) TM color image products should contain a spectral band in the visible (bands 1, 2, or 3), near infrared (band 4), and middle infrared (band 5) regions for maximizing the interpretability of vegetation types; (2) TM color composites should contain band 4 in all cases even at the expense of excluding band 5; and (3) MSS color composites were more interpretable than all TM color composites for certain cover types and for all cover types when band 4 was excluded from the TM composite.

Benson, A. S.↗
NASA NTRS1985

Characterization and comparison of Landsat-4 and Landsat-5 Thematic Mapper data

Engineering analyses of Thematic Mapper (TM) image data have been conducted, giving particular attention to the radiometric characterization of the sensor. While the data in general were found to be excellent, anomalies do exist in the data from both Landsat-4 and Landsat-5 TM. A summary is provided of the Landsat-4 TM image data. The present paper concentrates, however, on recent analyses of Landsat-5 TM data and comparisons of the radiometry of the two sensors. One of the specific topics covered is within-line droop, a phenomenon whereby the signal levels of the sensor change systematically during the active scan. Attention is also given to scan-correlated level shifts, an effect which raises or lowers the signal level of all pixels in a scan line or set of scan lines. A comparison of Landsat-4 and Landsat-5 radiometric corrections is also discussed.

Metzler, M. D.↗
NASA NTRS1985

Landsat Thematic Mapper image-derived MTF

The Landsat Image Data Quality Analysis (LIDQA) Program conducted by NASA has the objective to quantify the performance of the Thematic Mapper (TM) on the Landsat-4 and Landsat-5 spacecraft. The interest in the spatial resolution performance of the TM is partly related to the decrease of the instantaneous field of view (IFOV) from 80 m for the MSS to 30 m for the TM. Studies related to the preflight line spread function (LSF), square wave response (SWR), and theoretical component modeling of the TM system modulation transfer function (MTF) have been conducted. However, the need remains to estimate the MTF of the complete system. The present paper is concerned with investigations related to this task. Attention is given to three approaches for measuring the MTF of the TM system from imagery.

Schowengerdt, R. A.↗