Color Composite Images Research Articles

Identifying fine-scale archaeological features using KH-9 HEXAGON mapping and panoramic camera images: evidence from Liangzhu Ancient City

ABSTRACT Historical fine-scale information of archaeological landscapes is crucial in archaeological investigations. However, documenting such information using satellite sensor data prior to 2000 remains a daunting challenge. Images from the declassified archives of KH-9 HEXAGON (KH-9) cameras, including the panoramic camera system (PCS) and mapping camera system (MCS), offer fine-scale information about archaeological sites. However, noise, contrast distortion and the availability of only a single panchromatic band can limit their potential, particularly for identifying features in subtropical climates within heterogeneous landscape types. This paper focuses on developing a novel multifaceted analytical framework with two components: image pre-processing and feature identification. The image pre-processing component is divided into two steps. First, a trained stationary wavelet transform (SWT) based on the normalized sill (NS) is developed to not only de-noises the image, but also preserve its original image characteristics. Then, the contrast of the de-noised images is optimized by the multi-resolution Top-hat (MTH) using multi-scale information. In the feature identification component, the MCS image is analysed using spatial colour composite write function memory (SCCWFM) and spatial novelty detection (SND). An ultra-fine spatial three-dimensional colour composite (UFSTCC) image and ultra-fine spatial digital surface model (UFSDSM) are produced to aid interpretation of the KH-9 PCS images. The proposed processing pipelines were tested on KH-9 MCS and PCS images of the World Heritage site at Liangzhu Ancient City (LAC) in China, which is characterized by a subtropical climate and a heterogeneous landscape types. The proposed pre-processing pipeline improved considerably the appearance of these images across the LAC landscape while maintaining the original image information. The developed digital analytical approaches for KH-9 PCS and MCS images facilitated straightforward identification of archaeological features in the LAC. The proposed framework has the potential to increase exploitation of the available KH-9 images in archaeological applications.

Geological controls of mineralization occurrences in the Egyptian Eastern Desert using advanced integration of remote sensing and magnetic data

This study presents a comprehensive analysis of mineralization exploration in the Egyptian Eastern Desert (ED), one of the most sought-after areas for those interested in mining industry, by integrating Landsat-9 images and geophysical magnetic data. Employing advanced techniques like Principal Component (PC) analysis, Minimum Noise Fraction (MNf) transform, and Band-Ratio (B-Ratio), the research focuses on mapping lithological units, hydrothermal alteration regions, and structural elements. Composite images derived from specific PC, and MNf bands, and B-Ratio exhibit superior lithological unit identification. The findings emphasize that there are significant variations in the types of rocks extend from the southern to the northern parts of the ED. Hydrothermal alteration mapping, guided by B-Ratio results, aids qualitative lithological discrimination. A novel false color composite image optimizes Landsat-9 B-Ratios, enhancing rock unit discrimination. Correlation analyses reveal associations between mineralization types and major lithological units, while exploration of the magnetic anomaly map highlights its role in correlating mineralization sites. Structural features, analyzed through Center for Exploration-Targeting Grid-Analysis (CET-GA) and Center for Exploration-Targeting Porphyry-Analysis (CET-GA) with Tilt Derivative of RTP (TDR) techniques, contribute to a robust association between regions with medium to high structural density and porphyry intrusions and mineralization. The study significantly supports the advanced exploration geoscience, providing insights into the geological structures and dynamics governing mineralization in the Egyptian ED.

Integrative mapping of radioactive and alteration zones in Um Had plutons, Egypt: Using Landsat 9, ASTER imagery, and airborne geophysical data

The study aims to assess the effectiveness of using ASTER, Landsat 9, and airborne geophysical data to generate maps depicting hydrothermally altered regions and their correlation with radioactive-mineralized zones in Egypt's Um Had area. Various image processing methods were applied, including color composite images, band ratios, selective principal component analyses, and lineament extraction with enhancement procedures. The ASTER ratios identified the three types of hydrothermal alterations; phyllic, argillic, and propylitic, with other significant alteration zones related to mineralization. Airborne gamma-ray spectrometry contour maps displayed marked varied levels of total count (T.C), eU, eTh, and K, ranging from 1.2 to 21.2 Ur, 0.5–12.34 ppm, 1.45–28 ppm, and 0.13–3.65 %, respectively. The highest anomalies of these radioelements concentration have coincided with the alkali feldspar granite and along their intrusive contact zone with the Hammamat Group sedimentary rocks. Higher anomalies are well recorded in the center and eastern regions of Um Had's, according to the radioelements composite image. The lowest concentrations of these radioelements are associated with gneiss, ophiolitic mélange, metavolcanic, Hammamat Group sedimentary rocks, Taref Formation, and Wadi sediments. To mitigate local magnetic effects, the total aeromagnetic data was reduced to the north magnetic pole (RTP). Power spectrum analysis of the RTP data identified distinct magnetic wavelengths for regional-residual components. In order to identify near-surface magnetic lineaments, such as contacts, shear zones, faults, and dykes, advanced algorithms were applied to the RTP data. The lineaments derived from ASTER and airborne magnetic data revealed dominant fault systems characterized by E–W, NE, NNW, NW and N–S trends, governing the structural framework of the study area. Depth levels of geological contacts and faults that represented pathways for altered and mineralized zones reached more than 1200 m (Euler deconvolution). These findings highlight the consistent results obtained when combining ASTER data with airborne survey data, allowing for the identification of hydrothermally altered zones and primary conductive zones.

Distribution of Merging and Post-merger Galaxies in Nearby Galaxy Clusters

We study the incidence and spatial distribution of galaxies that are currently undergoing gravitational merging (M) or that have signs of being post-merger (PM) in six galaxy clusters (A754, A2399, A2670, A3558, A3562, and A3716) within the redshift range of 0.05 ≲ z ≲0.08. To this aim, we obtained Dark Energy Camera mosaics in the u′ , g′ , and r′ bands covering up to 3 × R 200 of the clusters, reaching 28 mag arcsec−2 surface brightness limits. We visually inspect u′ g′ r′ color-composite images of volume-limited (M r < −20) cluster member galaxies to identify whether galaxies are of M or PM type. We find 4% M-type and 7% PM-type galaxies in the galaxy clusters studied. By adding spectroscopic data and studying the projected phase-space diagram (PPSD) of the projected clustocentric radius and the line-of-sight velocity, we find that PM-type galaxies are more virialized than M-type galaxies, having a 1%–5% higher fraction within the escape-velocity region, while the fraction of M-type was ∼10% higher than the PM type in the intermediate environment. Similarly, on a substructure analysis, M types were found in groups in the outskirts, while PM-type populated groups were found in ubiquitous regions of the PPSD. Adopting literature-derived dynamical state indicator values, we observed a higher abundance of M types in dynamically relaxed clusters. This finding suggests that galaxies displaying post-merger features within clusters likely merged in low-velocity environments, including clusters outskirts and dynamically relaxed clusters.

Foreground Dust Properties toward the Cluster NGC 7380

Using starlight polarization, we present the properties of foreground dust toward cluster NGC 7380 embedded in H ii region Sh 2-142. Observations of starlight polarization are carried out in four filters using an imaging polarimeter equipped with a 104 cm ARIES telescope. Polarization vectors of stars are aligned along the Galactic magnetic field. Toward the east and southeast regions, the dust structure appears much denser than in other regions (inferred from extinction contours and a color composite image) and is also reflected in polarization distribution. We find that the polarization degree and extinction tend to increase with distance and indication for the presence of a dust layer at a distance of around 1.2 kpc. We have identified eight potential candidates exhibiting intrinsic polarization by employing three distinct criteria to distinguish between stars of intrinsic polarization and interstellar polarized stars. For interstellar polarized stars, we find that the maximum polarization degree increases with the color excess and has a strong scatter, with the mean value of 1.71% ± 0.57%. The peak wavelength spans 0.40–0.88 μm, with a mean value of 0.56 ± 0.07 μm, suggesting similar grain sizes in the region to those in the average diffuse interstellar medium. The polarization efficiency is also found to decrease with visual extinction as Pmax/AV∝AV−0.61 . Our observational results are found to be consistent with the predictions by the radiative torque alignment theory.

Lithological discrimination of the Fawakhir-Atalla belt in the Central Eastern Desert of Egypt based on Landsat-9 remote sensing data, airborne gamma-ray spectrometry, field and petrographic investigations with implications on the evolution of the Arabian Nubian Shield

The Central Eastern Desert (CED) is a key territory for understanding the evolution of the Arabian Nubian Shield (ANS) in Egypt as it contains Cryogenian-Tonian ensimatic supracrustal assemblages, such as ophiolitic and arc volcanic rocks, as well as gold deposits. So, it has been the subject of extensive studies over the last two decades. However, the lithological mapping of the Fawakhir-Atalla belt, located west of the Meatiq gneiss dome (infrastructure) of the CED, is still debated, as the magmatic texture of some rocks was partially obscured owing to the shearing and alteration related to the Najd Fault System, mantle CO2-bearing fluid, and igneous activity in the final stage of the Pan-African Orogeny. In this regard, integrated studies of airborne gamma-ray spectrometry and Landsat-9 satellite imagery processing techniques, as well as field and petrographic investigations, have been used for the lithological mapping of the belt. The results led to the following sequence; ophiolitic rocks > island arc assemblages > older granitoids (syn-tectonic subduction-related) > Hammamat Group (molasse-type origin) > post-Hammamat felsite > younger granite (post-tectonic suture-related). The applied color composite images, selective band ratios, and image transformation techniques show a clear distinction between rock units. Older granitoids are tonalite to quartz diorite, while younger granites are monzo-to syenogranite. They are well-discriminated from each other using band ratios, and younger granites have the highest K, eU, and eTh values coherent with the post-Hammamat felsite. The image enhancement and image transformation techniques show a clear discrepancy between the mélange rocks and Hammamat conglomerates. Mélange rocks are composed of fragments embedded in a foliated matrix, while Hammamat conglomerates are grain-supported with pebbles of volcanic source and have higher K, eU, and eTh values. Volcanic rocks in the belt are not a part of the Dokhan series as they are metamorphosed with a composition range from meta-basalts to meta-rhyolite, and show mainly aphanitic to infrequently porphyritic textures, which are typical of island arc metavolcanics.

Land use and land cover mapping using Landsat-8 and Sentinel-2 data in Al Qunfudhah coast, western Saudi Arabia: A comparative study

Al Qunfudhah Governorate has assumed a tourist status in the strip of Saudi coastal cities on the Red Sea coast. Agriculture, food industries, and engineering industries are among the most important economic activities in the city. As a result, Land use and land cover (LULC) detection is essential for several reasons: urban planning, sustainability, resource management and environmental preservation. This research aims to identify the LULC of the Al Qunfudhah area in western Saudi Arabia by comparing Landsat-8 and Sentinel-2 data outputs and evaluating their accuracy results. Various methods are used to process satellite image data to enhance the contrast between surface features. Some of these techniques are true colour composite (TCC) images, enhanced true colour composite (ETCC) images, false colour composite (FCC) images, principal component analysis (PCA), band ratios and Maximum Likelihood Algorithm (MLA) Supervised Classification. By utilising band combination methods, PCA methods, and band ratio methods, we were able to map a variety of features, including vegetation cover, mangroves, Sabkha and non-Sabkha deposits, wadi basins, shallow and deep shelf areas, islands, sand and mud sediments, rocky reefs and urban areas. As part of the study, ArcGIS 10.8's supervised classification tool was employed to categorise the study region's features and calculate the percentage of each class. In both Landat-8 and Sentinel-2 classification images, the same classes were identified (i.e. sand and mud sediments, sabkhas, wadi basins, aeolian sand and loess sediments, islands, urban areas, vegetation, and mangroves). The accuracy of the classification results was determined using a reliable statistical approach. The accuracy assessments of Landsat-8 and Sentinel-2 revealed accuracy rates of 87% and 89.1% respectively, along with kappa coefficients of 84.9% and 87.3%. For the investigated area, the Landsat-8 and Sentinel-2 satellites were effective in producing LULC maps.

Application of Integrated Geophysical Methods in Mapping the Location of Basaltic Intrusions in Mambilla Plateau and Environs, Northeast, Nigeria

Integrated geophysical investigation on the Mambilla Plateau and its environs was necessary to map the locations of basaltic intrusions and their patterns of distribution. The Landsat-8 ETM+ false colour composite image (bands 7, 4, 2 in R, G, and B) was used to identify rocks such as younger basalt (yb), porphyritic granite (pg), granite gneiss (Gn), and migmatite gneiss (Mg). Similarly, rocks like granite gneiss (Mg), porphyritic granite (pg), and migmatite gneiss (Mg) were recognised by the Principal Component Analysis of the Landsat 8 ETM+ picture (PC2, PC1, and PC4 in R, G, and B). The lowest and maximum values for the total magnetic intensity map were 33030.343 nT and 33172.792 nT, respectively, along with mean of value 31.50nT to 33068.89nT.The primary magnetic field map showed an average value of 33293.4495 nT, with values ranging from 33228.522nT to 33358.377nT. The crustal magnetic field map resulting from ore bodies or intrusions had an average value of -159.50 nT, with values ranging from -397.669 nT to -80.699 nT. The RTE values, which range from -82.382nT to -392.122nT, indicate regional geological intrusions, fractures, and faults. Values were shown on the magnetic equator field map, which was further upward continued to 15 km, with an average values ranging from -279.141nT to -157.160nT. The pseudo-gravity map of the region showed two low densities, ranging from -0.11 to -0.01 mGal, depending on the location, and three high densities, indicating moderate to intermediate densities, ranging from 0.25 mGal to 0.01 mGal. RTE anomaly data produced from subsurface rocks typically has the greatest horizontal gradient along the object's border. This means that the maximum gradient is directly localised to the map boundaries of the distinct lithologies. By examination of the abrupt changes in rock magnetism in a lateral direction, this led to the determination of contact limits of the basaltic intrusion, faults, and mineralization of the underlying rocks

Deep learning-assisted inverse design of metasurfaces for active color image tuning.

Metasurfaces, artificial planar nanostructures, offer numerous advantages for color printing applications, including ultra-high resolution, resistance to fading, wide color gamut coverage, and multifunctional capabilities. Due to the sensitivity of their resonance spectra to the external environment, metasurfaces have garnered significant interest for color tuning applications. However, most existing approaches are limited to passive color tuning, wherein only the color changes passively while the composite color image remains unaltered. Active color image tuning, on the other hand, requires precise matching of both color and intensity to the designed targets before and after the tuning process. In this study, we propose a novel approach for active metasurface color image tuning by modulating the environmental refractive index. Building upon a forward neural network that establishes the relationship between the metasurface geometric parameters and color/intensity information, we employ a multi-objective inverse adjoint neural network. This network not only overcomes the inherent 'one-to-many' problem in inverse design using neural networks but also facilitates active color image tuning under three distinct environmental conditions. Our work provides a new approach for the inverse design of metasurfaces and opens up possibilities for applications in dynamic color printing, information encryption, and other related fields.

Water Body Extraction of the Weihe River Basin Based on MF-SegFormer Applied to Landsat8 OLI Data

In the era of big data, making full use of remote sensing images to automatically extract surface water bodies (WBs) in complex environments is extremely challenging. Due to the weak capability of existing algorithms in extracting small WBs and WB edge information from remote sensing images, we proposed a new method—Multiscale Fusion SegFormer (MF-SegFormer)—for WB extraction in the Weihe River Basin of China using Landsat 8 OLI images. The MF-SegFormer method adopts a cascading approach to fuse features output by the SegFormer encoder at multiple scales. A feature fusion (FF) module is proposed to enhance the extraction of WB edge information, while an Atrous Spatial Pyramid Pooling (ASPP) module is employed to enhance the extraction of small WBs. Furthermore, we analyzed the impact of four kinds of band combinations on WB extraction by the MF-SegFormer model, including true color composite images, false color images, true color images, and false color images enhanced by Gaussian stretch. We also compared our proposed method with several different approaches. The results suggested that false color composite images enhanced by Gaussian stretching are beneficial for extracting WBs, and the MF-SegFormer model achieves the highest accuracy across the study area with a precision of 77.6%, recall of 84.4%, F1-score of 80.9%, and mean intersection over union (mIoU) of 83.9%. In addition, we used the determination coefficient (R2) and root-mean-square error (RMSE) to evaluate the performance of river width extraction. Our extraction results in an overall R2 of 0.946 and an RMSE of 28.21 m for the mainstream width in the “Xi’an-Xianyang” section of the Weihe River. The proposed MF-SegFormer method used in this study outperformed other methods and was found to be more robust for WB extraction.

Rock type discrimination using Landsat-8 OLI satellite data in mafic-ultramafic terrain

The mafic-ultramafic terrain of the Bhavani complex in southern India is considered for lithological mapping. The Landsat-8 OLI satellite data was used for the interpretation of different rock types in the study area. The satellite data were digitally processed using ENVI 5.6 image processing software. In the OLI data, excluding bands 8 and 9, the remaining seven bands were used for the generation of colour composite images, band ratios, principal component analysis and SVM classification. Reflectance spectral measurements were carried out in laboratory conditions for five rock samples collected from the study area. The XRF analysis was carried out to estimate the composition of major oxides present in the rock samples. The results obtained from XRF analysis were compared with the rock spectra in characterizing the spectral features of the rock types. The colour composite images (B543, B567, B456, and B457), PCA composite image (PC312 and PC456), band ratios (BR5/5 and BR4/3), colour composite images from band ratios, and SVM classified output are useful in delineation various rock types in the terrain.

Using the band ratio approach, FULL-PIXEL (SAM and SFF) and SUB-PIXEL (MF and SID) methodologies to discover areas with alteration using the Aster sensor: a case study in north westen Iran - Sivardaghi Area

ASTER sensor data is among the most potent satellite data accessible for doing geological investigations, with images for the whole earth's surface. In order to test the capability of this sensor to detect places with geochemical alterations, photographs of Mount Seiver Daghi in the western Iranian province of Samal were utilized in this study. This region, which comprises of magmatic and volcanic terrain, is part of the Arsbaran territory and is covered by intrusive masses with alluvial and sedimentary deposits. To conduct this study, an ASTER measuring frame was utilized, which, after performing atmospheric corrections using the internal average relative reflectance (IARR) method of false color composite images and principal component analysis (PCA), was able to differentiate between different lithological units using the Band assignment method, full-pixel methods of spectral angle mapper (SAM) and base spectrum algorithm of spectral feature fitting (SFF) as well as sub-pixel methods of matched filtering. The study demonstrates that the approach of principal component analysis and false color composition is efficient for distinguishing sedimentary rock units from igneous rock units, and its application is suggested for the designated rock units. Due to the lack of spectral characteristics of feldspars and quartz in the short infrared wavelength range, the basic spectrum methods utilized in this work are incapable of identifying such minerals. It is not advised to use these algorithms to distinguish between various magmatic units.

Impact of land use land cover change on the land surface temperature: A case study of Shillong

Shillong has been experiencing changes in land use land cover over the past years especially in the town areas where a lot of built-ups are emerging. In response to this, there has been some impacts in the distribution of temperature. In this study, remote sensing techniques have been used. The maximum likelihood method has been used for supervised classification of land use land cover from false color composite images. Landsat 5 TM and Landsat 8 OLI/ TIRS has been used in this study. The study period is 30 years from 1992 - 2022 with an interval of 15 years. The emergence and increase of more built-up and impervious land cover type surfaces has made the land surface temperature to increase. The correlation between NDVI and LST shows a negative relationship while that of NDBI and LST shows a positive relationship. The temperature has been increasing with an average of 2° C each interval of study. The hotspot analysis has been used to demarcate the heat zones. The highest temperature is found in the crowded and high built-up areas while the lowest temperature is found in the vegetated lands which further cause heat island effect in these highly built-up areas. Key Words: Land use land cover, Land surface temperature, Change detection, Hotspot analysis, Correlation analysis, Heat-island effect.

Integration of remote sensing and geophysical methods for structural and lithological mapping in a part of Precambrian Basement Rocks, northern Nigeria

Landsat 8 OLI data, Aeromagnetic data, and Radial Vertical Electrical Sounding (RVES) survey data were integrated to map lithology, delineate structures and their trends, and delineate possible mineralized zones in the area. Landsat 8 OLI data yielded a color composite image, and surface lineaments map of the area. The aeromagnetic maps were utilized to map lithology, and subsurface structures. A radial survey confirmed the fractures derived from the structural maps. Results classified the area into three geological units viz: migmatite, banded gneiss, and quartzite. The banded gneiss is the most deformed and contains series of structures that are significant for mineral and groundwater explorations. Clay alteration is the most dominant in the area, followed by iron oxide alterations. Lineament alignments are N-S, NNW-SSE, NNE-SSW, NE-SW, and E-W directions.

Early Results from GLASS-JWST. XVIII. A First Morphological Atlas of the 1 < z < 5 Universe in the Rest-frame Optical

We present a rest-frame optical morphological analysis of galaxies observed with the NIRCam imager on the James Webb Space Telescope (JWST) as part of the GLASS-JWST Early Release Science program. We select 388 sources at redshifts 0.8 < z < 5.4 and use the seven 0.9–5 μm NIRCam filters to generate rest-frame gri composite color images, and conduct visual morphological classification. Compared to Hubble Space Telescope (HST)–based work we find a higher incidence of disks and bulges than expected at z > 1.5, revealed by rest-frame optical imaging. We detect 123 clear disks (58 at z > 1.5) of which 76 have bulges. No evolution of bulge fraction with redshift is evident: 61% at z < 2 (N = 110) versus 60% at z ≥ 2 (N = 13). A stellar mass dependence is evident, with bulges visible in 80% of all disk galaxies with mass >109.5 M ⊙ (N = 41) but only 52% at M < 109.5 M ⊙ (N = 82). We supplement visual morphologies with nonparametric measurements of Gini and asymmetry coefficients in the rest-frame i band. Our sources are more asymmetric than local galaxies, with slightly higher Gini values. When compared to high-z rest-frame ultraviolet measurements with HST, JWST shows more regular morphological types such as disks, bulges, and spiral arms at z > 1.5, with smoother (i.e., lower Gini) and more symmetrical light distributions.

Preliminary Site Investigation based on RGB Electromagnetic Energy of Landsat-7 Images in Wadi Fayidah, Saudi Arabia

In this paper, geostatistical analysis of digital image processing data efficiently contributed to the preliminary site investigation and geotechnical mapping of Wadi Fayidah, Saudi Arabia. 3D modeling, clustering, and chart pattern changes were used to analyze the spectral electromagnetic energy reflected values in red, green, and blue (RGB) ranges on false color composite Landsat-7 images. Therefore, from upstream to downstream, a series of measurements were carried out on a 70km dendritic drainage pattern at 78 stations. Wadi Fayidah was found to have a dominant structural lineament of 56° to 84°. Furthermore, as a preliminary engineering geology mapping, Wadi Fayidah has 9 lithofacies that may differ in engineering geological properties.

A reconnaissance study for tracing and ordering new mineralisation zones using integrated remote sensing, GIS, and aeromagnetic techniques, west Allaqi-Heiani-Suture,Egypt

ABSTRACT Reducing expenses is a critical aspect of natural resource explorations, especially in the reconnaissance stage. Accordingly, GIS algorithms using the free remote sensing data were used to rank the probable mineralised zones before any future implementations of the high-cost drilling and/or detailed geophysical programmes. Geological and tectonic settings, and being a historical mineral resource were motivations to choose the Allaqi-Heiani Suture (AHS), Upper Egypt, as a study area. Remote sensing data were processed for tracing the probably mineralised alteration zones, determining fractures and dominating structural systems, and mapping different geological units. Various alteration minerals including hydroxyls–carbonates, ferrous and ferric iron oxides were detected over different rock units using band ratio (BR) and Crosta techniques. Different geological units were distinguished using false colour composite (FCC) images. Moreover, an intense fractured system, demonstrating the area, was revealed by tracing lineaments using informative, spatially enhanced remote-sensed images. Fractures within the altered rocks represent 35% of the total fracturing system in the AHS to indicate a structural system controlling mineralisation occurrences. The processing of magnetic data suggested a deep/buried nature of these remotely detected lineaments/structures. Reduced to pole (RTP) and tilt derivative (TDR) maps detected the buried magnetic sources, whereas zero contours of TDR, Euler deconvolution, analytic signal and source parameter imaging (SPI) techniques traced buried contacts/structures and estimated their depths. A GIS strategy depending on the intensity of the fracturing system and the presence of more than one type of alteration was applied to potential-rank the prospective mineralised occurrences over AHS. The correlation between ranked zones with the old/known mines showed encouraging evaluation.

Understanding the mineralogy of a compositional anomaly north of the Korolev basin using Moon mineralogy mapper

The work attempts to understand the mineralogy of the reported geochemical anomaly located in the north – northeast region of the Korolev basin using Moon Mineralogy Mapper (M3) onboard Chandrayaan −1 and other lunar datasets. To understand the mineralogy, colour composite images using integrated band depth parameters and mineral indices were prepared, and the M3 spectral signatures corresponding to the unique colours of these colours composites were investigated. Further, Modified Gaussian Model (MGM) deconvolution was applied to these spectra. The results of spectra studies reveal that the area is made up of heterogeneous lithologies, predominantly composed of anorthosite along with minor occurrences of pyroxene-bearing (both low-calcium and high-calcium variety) and spinel-bearing lithologies. Correlation of spectral studies with the morphology revealed that pyroxene was typically associated with fresh craters and their ejecta. Spinel was found to be ubiquitous and is well-dispersed, possibly distributed along with the ejecta blanket of large impact craters. This association hints that the pyroxene-hosted layer most likely occurs beneath the spinel-bearing layer. Such observed assemblages may have resulted from physical mixing during the impact cratering events. This mixed lithology could arise due to the mafic mineral-bearing ejecta of the South-Pole Aitken (SPA) basin and spinel-bearing Orientale ejecta. Korolev most likely impacted on a thick layer of SPA ejecta, and impact basins such as Hertzsprung and Orientale have occurred post-Korolev formation. Orientale being the youngest of the large impact basins, its ejecta carrying the light plain material would have overprinted the older SPA ejecta. Smaller impact craters would have churned the ejecta so that presently we observe a composite lithology with a variable abundance of pyroxene and spinel.

Evaluation of effectiveness of supervised classification algorithms in land cover classification using ASTER images-A case study from the Mankweng (Turfloop) Area and its environs, Limpopo Province, South Africa

The production of land cover maps using supervised classification algorithms is one of the most common applications of remote sensing. In this study, the effectiveness of supervised classification algorithms in land cover classification using ASTER data was evaluated in the Mankweng Area and its environs. The false colour composite image generated from combination of band 1, 2 and 3 in red, green and blue, respectively, was used to generate training classes for six land cover types (waterbody, forest, vegetation, Duiwelskloof leucogranite, Turfloop granite and built-up land). These were used to construct land cover maps using eight supervised classification algorithms: Maximum Likelihood, Minimum Distance, Support Vector Machine, Mahalanobis Distance, Parallelepiped, Neural Network, Spectral Angle Mapper and Spectral Information Divergence. To evaluate the effectiveness of the algorithms, the land cover maps were subjected to accuracy assessment to determine precision of the algorithms in accurately classifying the land cover types and level of confidence that can be attributed to the land cover maps. Most algorithms poorly performed in classifying spatially overlapping land cover types without abrupt boundaries. This indicates that the environmental conditions and distribution of land cover types can affect the performance of certain classification algorithms, and thus need to be considered prior to selection of algorithms. However, Support Vector Machine and Minimum Distance proved to be the two most effective algorithms as they provided better producer’s and user’s accuracy in the range of 80-100% for all land cover types, which represent good classification.

Mineralogical Studies and Radioactivity on Stream Sediments Around Wadi Aidib Area, South Eastern Desert, Egypt

Wadi Aidib lie at southern part of the Eastern Desert of Egypt, between 22° 15’ - 22° 21’ N and Longitudes 36° 20’ - 36° 30’ E, covering an area of about 30km2. It is covered by basement rocks dissected by several wadies, Wadi Aidib as a main wadi with several tributaries. Constant of channel maintenance showed the dissection of the studied basin by lineaments, fractures and joints, dissection is minimized in wadi Aidib. Landsat ETM+ false color composite image (bands 3, 2, 1) The rock types wide spread out at Wadi Aidib area contains metavolcanics, alkali feldspar granites, quartz diorites, biotite granites metasediments. Heavy liquid separation and magnetic separation techniques in addition to microscopic examination for the studied stream sediment samples were applied. The mineral resource tonnage for each concerned economic mineral 171.315 ilmenite; 93.150, magnetite; 25.110, zircon; 9.720, total rutile; 7.695, garnet; 1.215, monazite and 810.000 green silicates, in thousands of tons. The studied stream sediments are measured radiometrically using gamma-ray spectrometer for determination the radionuclides contents. U concentration varies between 1 and 2 ppm with 1.69 as an average, Th from 3 to 7 ppm with an average 4.92 ppm.