THE EFFECT OF TOPOGRAPHIC CORRECTION METHODS SUN CANOPY SENSOR + C CORRECTION (SCS + C) ON THE ACCURACY OF THE RESULTS OF VARIOUS CLASSIFICATION METHODS IN LANDSAT 8 SURFACE REFLECTANCE IMAGE

In the land cover classification process using the optical system remote sensing satellite data, there are problems in hilly areas where the lighting on the slopes facing or backward from the sun produces different spectral responses. In this study, we will analyze the effect of topographic correction on the Sun Canopy Sensor + C Correction (SCS + C) method on the accuracy of the classification results on the LANDSAT 8 surface reflectance image using Google Earth Engine (GEE). The results showed an increase in classification accuracy after topographic correction using the Support Vector Machine (SVM) method, Classification and Regression Tree (CRT), Random Forest (RF), and Minimum Distance (MD), respectively 4.45%, 3.33%, 2.23%, and 2.22%. The topographic correction applied to the Maximum Entropy (ME) classification methods failed to improve accuracy. It can be concluded that topographic correction can improve the accuracy of land cover classification results, especially in hilly area

Theoretical Evaluation of Anisotropic Reflectance Correction Approaches for Addressing Multi-Scale Topographic Effects on the Radiation-Transfer Cascade in Mountain Environments

Research involving anisotropic-reflectance correction (ARC) of multispectral imagery to account for topographic effects has been ongoing for approximately 40 years. A large body of research has focused on evaluating empirical ARC methods, resulting in inconsistent results. Consequently, our research objective was to evaluate commonly used ARC methods using first-order radiation-transfer modeling to simulate ASTER multispectral imagery over Nanga Parbat, Himalaya. Specifically, we accounted for orbital dynamics, atmospheric absorption and scattering, direct- and diffuse-skylight irradiance, land cover structure, and surface biophysical variations to evaluate their effectiveness in reducing multi-scale topographic effects. Our results clearly reveal that the empirical methods we evaluated could not reasonably account for multi-scale topographic effects at Nanga Parbat. The magnitude of reflectance and the correlation structure of biophysical properties were not preserved in the topographically-corrected multispectral imagery. The CCOR and SCS+C methods were able to remove topographic effects, given the Lambertian assumption, although atmospheric correction was required, and we did not account for other primary and secondary topographic effects that are thought to significantly influence spectral variation in imagery acquired over mountains. Evaluation of structural-similarity index images revealed spatially variable results that are wavelength dependent. Collectively, our simulation and evaluation procedures strongly suggest that empirical ARC methods have significant limitations for addressing anisotropic reflectance caused by multi-scale topographic effects. Results indicate that atmospheric correction is essential, and most methods failed to adequately produce the appropriate magnitude and spatial variation of surface reflectance in corrected imagery. Results were also wavelength dependent, as topographic effects influence radiation-transfer components differently in different regions of the electromagnetic spectrum. Our results explain inconsistencies described in the literature, and indicate that numerical modeling efforts are required to better account for multi-scale topographic effects in various radiation-transfer components.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The Algorithm Theoretical Basis Document for the Derivation of Range and Range Distributions from Laser Pulse Waveform Analysis for Surface Elevations, Roughness, Slope, and Vegetation Heights

The primary purpose of the GLAS instrument is to detect ice elevation changes over time which are used to derive changes in ice volume. Other objectives include measuring sea ice freeboard, ocean and land surface elevation, surface roughness, and canopy heights over land. This Algorithm Theoretical Basis Document (ATBD) describes the theory and implementation behind the algorithms used to produce the level 1B products for waveform parameters and global elevation and the level 2 products that are specific to ice sheet, sea ice, land, and ocean elevations respectively. These output products, are defined in detail along with the associated quality, and the constraints, and assumptions used to derive them

Earth resources: A continuing bibliography with indexes (issue 52)

This bibliography lists 454 reports, articles, and other documents introduced into the NASA scientific and technical information system between October 1 and December 31, 1986. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Deriving Planetary Surface Characteristics from Orbiting Laser Altimeter Pulse-Widths on: Mars, the Moon, and Earth

A set of equations linking the time-spread of a laser altimeter echo-profile, commonly known as the pulse-width, to the variance of topography within the pulse-footprint are tested by comparing pulse-width data to surface characteristics measured from high-resolution Digital Terrain Models. The research is motivated by the advent of high-resolution Digital Terrain Models over Mars, which enables the calibration of Mars Orbiter Laser Altimeter pulse-widths, and evolves to include lunar and terrestrial data in an attempt to validate the theory and develop new methods. Analysis of Mars Orbiter Laser Altimeter pulse-width data reveals mixed results. Over homo- geneously rough terrain, at kilometre-scales, these pulse-widths show some correlation to surface characteristics, once poor pulse data has been removed. However, where roughness is highly vari- able over short baselines, little correlation is observed, which is attributed to a mix of georeferencing errors and instrument methods. In a similar study, Lunar Orbiter Laser Altimeter pulse-widths are shown to produce only poor correlations with surface characteristics over local study sites. Instead, the observed correlations differ from orbit to orbit, with the majority of those used appearing to contain poor quality pulse- width data - attributed to the instrument methods - and only 14 % revealing correlations similar, or better, than observed over Mars. Finally, an examination of the relationship between footprint-scale surface characteristics and pulse-width estimates derived from smoothed Ice, Cloud, and land Elevation Satellite echo-profiles enables different pulse-width thresholds to be tested. Here, pulse-widths measured using a 10 % Peak Energy threshold are shown to produce greater correlations than those observed using the Mars Orbiter Laser Altimeter and the Lunar Orbiter Laser Altimeter data, which use a Full Width Half Maximum threshold. To conclude, pulse-widths can show strong correlations to surface roughness and slope within the pulse-footprint. However the assumption that detrended surface roughness can be derived by applying a slope contribution effect is shown to be unfounded. The principal recommendation is for future instruments to use a full echo-profile in estimating pulse-width values at a 10 % Peak Energy threshold, providing both efficient noise removal and a better correlated dataset

Earth resources: A continuing bibliography with indexes (issue 59)

This bibliography lists 518 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1 and September 30, 1988. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, oceanography and marine resources, hydrology and water management, data processing and distribution systems, and instrumentation and sensors

The data concept behind the data: From metadata models and labelling schemes towards a generic spectral library

Spectral libraries play a major role in imaging spectroscopy. They are commonly used to store end-member and spectrally pure material spectra, which are primarily used for mapping or unmixing purposes. However, the development of spectral libraries is time consuming and usually sensor and site dependent. Spectral libraries are therefore often developed, used and tailored only for a specific case study and only for one sensor. Multi-sensor and multi-site use of spectral libraries is difficult and requires technical effort for adaptation, transformation, and data harmonization steps. Especially the huge amount of urban material specifications and its spectral variations hamper the setup of a complete spectral library consisting of all available urban material spectra. By a combined use of different urban spectral libraries, besides the improvement of spectral inter- and intra-class variability, missing material spectra could be considered with respect to a multi-sensor/ -site use. Publicly available spectral libraries mostly lack the metadata information that is essential for describing spectra acquisition and sampling background, and can serve to some extent as a measure of quality and reliability of the spectra and the entire library itself. In the GenLib project, a concept for a generic, multi-site and multi-sensor usable spectral library for image spectra on the urban focus was developed. This presentation will introduce a 1) unified, easy-to-understand hierarchical labeling scheme combined with 2) a comprehensive metadata concept that is 3) implemented in the SPECCHIO spectral information system to promote the setup and usability of a generic urban spectral library (GUSL). The labelling scheme was developed to ensure the translation of individual spectral libraries with their own labelling schemes and their usually varying level of details into the GUSL framework. It is based on a modified version of the EAGLE classification concept by combining land use, land cover, land characteristics and spectral characteristics. The metadata concept consists of 59 mandatory and optional attributes that are intended to specify the spatial context, spectral library information, references, accessibility, calibration, preprocessing steps, and spectra specific information describing library spectra implemented in the GUSL. It was developed on the basis of existing metadata concepts and was subject of an expert survey. The metadata concept and the labelling scheme are implemented in the spectral information system SPECCHIO, which is used for sharing and holding GUSL spectra. It allows easy implementation of spectra as well as their specification with the proposed metadata information to extend the GUSL. Therefore, the proposed data model represents a first fundamental step towards a generic usable and continuously expandable spectral library for urban areas. The metadata concept and the labelling scheme also build the basis for the necessary adaptation and transformation steps of the GUSL in order to use it entirely or in excerpts for further multi-site and multi-sensor applications

Airborne thermography and ground geophysical investigation for detecting shallow ground disturbance under vegetation

This thesis discusses the potential of airborne thermal prospection for detecting shallow ground disturbance beneath vegetation based on images acquired by the NERC Airborne Thematic Mapper (ATM) at thermal infrared wavelengths. Shallow ground disturbance creates a differential heat flux due to a variation in the thermal properties between disturbed and undisturbed soils. When observed above a canopy, the effect of vegetation growth on the thermal regime of the underlying soils is poorly understood. The research extends current understanding by examining areas where ground disturbance is known to exist under variable vegetation cover at an archaeological site at Bosworth, Leicestershire and areas of abandoned mine activity on Baildon Moor, W. Yorkshire and in the N. Pennine Orefield, Weardale. The investigation focuses on qualitative image interpretation techniques, where anomalies on day and night thermal images are compared with those manifest on the multispectral images, and a more quantitative approach of Apparent Thermal Inertia (ATI) modelling. Physical thermal inertia is a parameter that is sensitive to volumetric variations in the soil, but cannot be measured directly using remote sensing techniques. However, an apparent thermal inertia is determined by examining the day and night temperature contrast of the surface, where spatial variations can signify potential features buried in the near-surface environment. Ground temperature profiling at the Bosworth site indicates that diurnal heat dissipates between 0.20-0.50m at an early stage in vegetation development with progressively lower diurnal amplitudes observed at 0.20m as the vegetation develops. Results also show that the time of diurnal maximum temperature occurs progressively later as vegetation develops, implying an importance for thermal image acquisition. The quantitative investigation concentrates on the Bosworth site where extensive ground geophysical prospection was performed and vertical soil samples extracted across features of variable multispectral, thermal and ATI response to enable comparison of the observed airborne thermal response with physical soil properties. Results suggest that there is a high correlation between ATI and soil moisture properties at 0.15-0.25m depth (R(^2)=0.99) at an early stage in cereal crop development but has a high correlation at a wider depth range (0.10-0.30m) at a later stage in development (R(^2)=0.98). The high correlation between physical ground disturbance and the thermal response is also corroborated qualitatively with the results of the resistivity surveys. The ATI modelling reveals similar features to those evident on day or night thermal images at an early stage in vegetation growth, suggesting that thermal imaging during the day at an early stage in vegetation growth may supply sufficient information on features buried in the near-surface environment. Airborne thermal imaging therefore provides a useful complementary prospection tool for archaeological and geological applications for surfaces covered by vegetation

Modeling quaternary geomorphic surfaces using laboratory, field, and imaging spectrometry in the lower Colorado Sonoran Desert : the Chameleon concept

Chameleon is a physics-based landscape modeling software system designed for modeling and simulations applications. Hyperspectral laboratory, field, and imaging spectrometer measurements are collected as empirical foundation data. Linear spectral unmixing is performed to decompose each image pixel into spectral endmembers. Mathematical manipulation of these fractional abundances and introduction of new spectral information is accomplished with spectral editing tools. Image spectra are modified on a sub-pixel, per-pixel, or neighborhood basis, or the entire hypercube can be customized at once. Chameleon then regenerates synthetic, but spectrally accurate, terrain models using linear spectral remixing algorithms. By incorporating elevation, sun angle, and weather data, the landscape becomes a "Chameleon"- able to change hyperspectral properties based on multitemporal spectral measurements, requirements for developmental tests and operational training, or as required by specific simulation scenarios. Advanced knowledge of natural environments to be modeled is prerequisite to generating useful synthetic terrains. Our spectral research on and Quaternary geomorphic surfaces suggests that deserts (often assumed to be less difficult to study remotely than humid, temperate, and cold environments) are more complex than is generally accepted. A variety of rock coatings can significantly alter reflectance in the solar reflected spectrum. Weathering rinds and carbonate deposits inhibit lithologic reflectance altogether. However, manganese-rich rock varnish obscures rock reflectance in the visible and near infrared wavelengths, but transmits lithologic information in the 2,000 to 2,500 nanometer (nm) wavelengths. Surface soils on desert pavements consist of a layer of eolian dust that overlies an accreting vesicular (Av) horizon. These soils have same structure and chemistry, and, therefore, the same hyperspectral signature, regardless of landform age, geomorphic process, or parent material. From a remote sensing perspective, this has a normalizing effect on reflectance across the landscape. Spectral Mixture Analysis is a proven hyperspectral technique for mapping composition and abundance of surface materials characteristic of volcanic landforms that exhibit diagnostic absorption features. We found that desert pavement spectra are featureless in that they exhibit few distinct spectral features related to rock varnish, clast lithology, or soil. Image spectra of these surfaces are the result of intimate mixtures of heterogeneous materials, requiring nonlinear spectral unmixing solutions