Browsing by Subject "Landsat satellites"
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Item A study of statistical image classification and enhancement(Texas Tech University, 1984-08) Tzeng, Mien-hueiNot availableItem An analysis of radiometric correction effects on Landsat thematic mapper imagery(1991-05) Waits, David Allan; Fish, Ernest B.; Wanjura, Donald F.; Wester, David B.; Davidson, Claud M.; Templer, Otis W.Land-use classifications and spectral indices are commonly created from raw radiance satellite data. These data are known to be distorted due to sensor instrumentation errors and atmospheric contributions. The overall objective of this study was to evaluate different radiometric corrections of Thematic Mapper (TM) data on land-use classification results and the derivation of spectral indices. A Landsat-4 TM digital image of a diverse agricultural area in the High Plains region of eastern New Mexico was the primary data source. Ancillary data incorporated into the study included: extensive field verification data for a study area of approximately 1,820 square kilometers; ground-based radiometer derived spectral response data for commonly grown agricultural crops; and meteorological data used as input parameters for atmospheric modeling using the Lowtran-7 atmospheric correction program. Four different geometrically corrected image data sets were analyzed. The first was raw radiance data in radiometrically uncorrected form. The other three images were radiometrically corrected transforms created using procedures that adjusted the raw data for radiometric calibration and atmospheric correction. All four images were classified in terms of land-use using identical training fields. Supervised classifications were developed using ground truth data, and quantitative analyses were performed on all resulting classifications. Ground-based spectral response data for various land-use types were compared qualitatively to response data derived from the raw and radiometrically corrected image data for the same land-use types. Four spectral index models were applied to each of the four image data sets. The derived spectral indices were transforms that emphasized the quantitative differences among image data sets. The results showed no material differences in classification accuracy among the four image data sets. Thus, it does not appear necessary to perform radiometric corrections on raw radiance data to improve classification accuracy. Spectra derived from atmospherically corrected image data sets more closely approximated "true" spectral response patterns as obtained by a ground-based radiometer. Each of the various components of the radiometric correction process was found to contribute significantly to the derivation of spectral index values.Item An evaluation of heat capacity mapping missions imagery as a tool for petroleum exploration(Texas Tech University, 1983-12) Fitzgerald, Jeffrey WNot availableItem Item Landsat photo-optic data analysis of land cover changes in the Middle Belt region of Nigeria(Texas Tech University, 1985-12) Alade, Oluwole Richardson AdedokunThe need for a standardized land-use classification scheme and an appropriate framework for acquiring land-use data to aid national development planning is imperative if Nigeria is to develop in a positive direction. Therefore, the usability of the Level-one U.S.G.S. land-cover classification categories with visual interpretation of LANDSAT imagery for acquiring land-use data was tested. The generalized Level-one U.S.G.S. classification model was used as a basis for inventorying land covers, and both inductive and deductive systems of land classification, based on the conventional polythetic photo interpretation of spectral discrimination, were used to analyze the photographic elements of the acquired images. Landcover patterns were inventoried, the types of land-cover changes were monitored, and the rates and magnitudes of land-use changes were assessed for the Experimental and Control Locations. Based on the results of in-situ verification of 108 randomly selected polygon samples from the generated landcover maps, interpretation accuracy was determined using the minimum acceptable level of 85% established by Professor J.R. Anderson in 1971. The planimeter measurement accuracy was determined at a stipulated j^5% error margin of the calculated areal sizes of each study location. The land-cover change types were enumerated for each study location; then, using the planimeter measurements acquired from the generated maps for both study years, the magnitudes and rates of land-cover changes were evaluated using the mathematical model employed by Dr. Peter Adeniyi. The statistical significance of the changes that had occurred in each study location between the two study years was determined at the 95% confidence level using the t-test. The results indicate that the U.S.G.S. land classification model is useable in a developing country. The relatively high interpretation and measurement accuracy percentages obtained imply that the interpretation technique and the measuring device are ideal for acquiring land-use data. Only the urban and farmland cover changes were of statistical significance.Item Remote sensing detection and geological interpretation of the eastern Snake River plain area, Idaho-Montana(Texas Tech University, 1986-08) Sikorski, Peter EdwinNot availableItem Use of Remote Sensing Techniques and Statistics in Petroleum Exploration: Permian Basin, Texas(Texas Tech University, 1982-12) Cox, Ricky GNot Available.