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1.
Airborne LiDAR has found application in an increasing number of mapping and Geo-data acquisition tasks. Apart from terrain
information generation, applications such as automatic detection and modeling of objects like buildings or vegetation for
the generation of 3-D city models have been explored. Besides the height itself, height texture defined by local variations
of the height is a significant parameter for object recognition. The paper explores the potential of the analysis of height
texture as a cue for the automatic detection of objects in LiDAR datasets. A number of texture measures were computed. Based
on their definition and computation these measures were used as bands in a classification algorithm, and objects like buildings,
single trees, and roads could be recognized. 相似文献
2.
The present work addresses the long-standing issues on the characterization aspect of the Proterozoic siliciclastic successions exposed in the central part of the Lesser Himalaya, restricted between the Main Boundary Thrust (MBT) and the Main Central Thrust (MCT). Geologic, sedimentologic, and petrographic study divides the Lesser Himalaya in two zones- northern Palaeo- Mesoproterozoic Inner Lesser Himalayan (ILH) and southern Neoproterozoic Outer Lesser Himalayan (OLH) zones. The major lithofacies recognized from the zones are - (i) coarse grained siliciclastic (CGS), (ii) interbedded medium and fine-grained siliciclastic (IMFS), (iii) argillite (ARG), and (iv) siliciclastic–argillite rhythmites (SAR). Amongst all these facies, the nearshore IMFS facies shows consistent presence in both OLH and ILH zones. From the facies distribution pattern, a northwest–southeasterly trending palaeo- shoreline has been envisaged. The CGS facies in the ILH hints towards an alluvial fan setting during 1.8 Ga rifting phase associated with penecontemporaneous basic magmatism. Compositionally, the siliciclastics of both the zones (ILH and OLH) are arenite and wacke types with minimal variation in their detrital proportions, derived from the early Proterozoic (between 2.4-1.6Ga) Aravalli-Delhi Supergroup provenance. Nearly matching types and content of detrital modes and the lithofacies pattern of the ILH and OLH siliciclastics probably conclude the derivation from the rising (nearby) Aravalli-Delhi orogen and deposition in a foreland like situation. 相似文献
3.
Hemant Kumar Singh Aswathi Thankappan Poonam Mohite Satish Kumar Sinha Dornadula Chandrasekharam Trupti Chandrasekhar 《Arabian Journal of Geosciences》2018,11(6):137
Tulsishyam thermal springs are located in the Saurashtra region of Gujarat, India with discharge temperatures varying from 39 to 42 °C. The pH of these thermal springs varies from 7.1 to 7.4, indicating neutral character. Though these thermal springs propagate through the near surface layer of Deccan basalt, detailed geochemical analysis of the thermal waters using Piper diagram suggests that the water is interacting with the granitic basement rock. Silica and cation geothermometry estimates have reservoir temperature in the range of 138 to 207 °C categorizing it into a low to moderate enthalpy geothermal system. Furthermore, the area has high heat flow values of 53–90 mW/m2 because of shallow Moho depth. The prevailing conditions suggest that the geothermal energy can potentially be exploited through an enhanced geothermal system (EGS). The study also indicates different mineral phases that may precipitate out of water during exploitation of geothermal energy and it should be taken into account while designing an EGS for the area. 相似文献
4.
Kapil Bisht Yogesh Joshi Shashi Upadhyay Poonam Metha 《Journal of the Geological Society of India》2018,92(2):173-176
Glaciers being very sensitive to climate change have been identified as one of the best indicators of climate change and evidences have proved that most of the Himalayan glaciers have receded with an increased rate during the recent past under the influence of global warming. Lichenometric study was carried out on the moraines of Milam glacier (located in Pithoragarh district of Uttarakhand) with the help of lichen species Dimelaena oreina having an average annual growth rate of 1.31 mm. The study revealed that Milam glacier has receded 1450 m in last 69.37 years with an average recession rate of 20.90 m/year. Since lichenometric studies are cost effective and ecofriendly in comparison to carbon dating, satellite and remote sensing based studies and also reliable, hence, it should be promoted in Himalaya which is an abode of glaciers. 相似文献
5.
The Nature and Distribution of Particulate Matter in the Mandovi Estuary,Central West Coast of India
Pratima Mohan Kessarkar Venigalla Purnachandra Rao Ranjan Shynu Prakash Mehra Blossom E. Viegas 《Estuaries and Coasts》2010,33(1):30-44
Systematic seasonal variations of suspended particulate matter (SPM) along a 44-km transect of the Mandovi estuary reveal
that the concentrations of SPM are low at river-end stations, increase generally seaward, and are highest at sea-end stations
of the estuary. An estuarine turbidity maximum (ETM) occurs at sea-end stations during June–September when river discharge
is high and also in February–May when river discharge is low. These are the two windiest times of year, the former associated
with the southwest monsoon and the latter characterized by a persistent sea breeze. The salinity vs. SPM plot shows that high
SPM is a seaward deposit and skewed landward. Suspended matter comprised of floccules, fecal pellets, and aggregates that
consist of clay and biogenic particles occur everywhere in the estuary. Diatoms are the most common and are of marine type
at the sea-end and freshwater-dominated at river-end stations of the estuary. SPM is characterized by kaolinite- and smectite-rich
clay mineral suites at the river- and sea-end stations, respectively. Smectite concentrations increase seawards with the increase
in SPM content and are not influenced by salinity. Wind-driven waves and currents and biogeochemical processes at the mouth
of estuary likely play an important role in the formation of ETM in resuspension and transformation of SPM into floccules
and aggregates and in their upkeep or removal. 相似文献
6.
Rohit Mehra Sandeep Kumar Rajendra Sonkawade N. P. Singh Komal Badhan 《Environmental Earth Sciences》2010,59(5):1159-1164
The activity concentration and the gamma-absorbed dose rates of the terrestrial naturally occurring radionuclides (232Th, 226Ra and 40K) were determined in soil samples collected from ten different locations of Sirsa district of Haryana, using HPGe detector
based on high-resolution gamma spectrometry system. The range of activity concentrations of 226Ra, 232Th and 40K in the soil samples from the studied areas varies from 19.18 Bq kg−1 (Moriwala) to 40.31 Bq kg−1 (Rori), 59.43 Bq kg−1 (Pipli) to 89.54 Bq kg−1 (Fatehpur) and 223.22 Bq kg−1 (Moriwala) to 313.32 Bq kg−1 (SamatKhera) with overall mean values of 27.94, 72.75 and 286.73 Bq kg−1 respectively. The absorbed dose rate calculated from activity concentration of 226Ra, 232Th and 40K ranges between 8.84 and 18.58, 37.02 and 55.78, and 9.24 and 12.97 nGy h−1, respectively. The total absorbed dose in the study area ranges from 60.40 to 82.15 nGy h−1 with an average value of 70.12 nGy h−1. The calculated values of external hazard index (H
ex) for the soil samples of the study area range from 0.36 to 0.49 with an average value of 0.42. 相似文献
7.
A rich palynological assemblage consisting of algal remains (5 genera and 7 species, including dinoflagellate cysts), fungal spores (2 genera and 3 species), pteridophytic spores (5 genera and 8 species), gymnospermous pollen grains (3 genera and 3 species) and angiospermous pollen grains (17 genera and 22 species) has been recorded for the first time from the Miocene sediments exposed along Kullur-Kavur road, near Mangalore along the west coast of Karnataka. Among the important genera are: Achomosphaera, Leptodinium, Staphlosporonites, Hammenisporis, Polypodiaceaesporites, Quilonipollenites, Myricipites, Graminidites, Malvacearumpollis, Palaeomalvaceaepollis and Chenopodipollis. Qualitative and quantitative analyses reveal that the angiosperm pollen grains are dominant over pteridophytic spores and an overall, a warm and humid tropical-sub-tropical coastal climate with heavy precipitation is suggested for the site of deposition. The sediments were deposited in fluctuating conditions ranging from lacustrine to marine environments with fresh water swamps and ponds nearby. The occurrence of Hammenisporis, Polypodiaceaesporites, Quilonipollenites, Myricipites, Graminidites, Malvacearumpollis, Palaeomalvaceaepollis and Chenopodipollis in the present assemblage suggests an early Miocene age. A comparison of the present palynofloral assemblage with those known from the Indian Tertiary sediments shows its close resemblances with the Miocene palynoflora recovered from Quilon and Warkalli beds of Kerala basin. 相似文献
8.
Pratima M. Kessarkar V. Purnachandra Rao R. Shynu Ishfaq Mir Ahmad Prakash Mehra G. S. Michael D. Sundar 《Journal of Earth System Science》2009,118(4):369-377
Systematic studies on the suspended particulate matter (SPM) measured on a seasonal cycle in the Mandovi Estuary, Goa indicate
that the average concentrations of SPM at the regular station are ∼20mg/l, 5mg/l, 19mg/l and 5mg/l for June–September, October–January,
February–April and May, respectively. SPM exhibits low-to-moderate correlation with rainfall indicating that SPM is also influenced
by other processes. Transect stations reveal that the SPM at sea-end stations of the estuary are at least two orders of magnitude
greater than those at the river-end during the monsoon. Estuarine turbidity maximum (ETM) of nearly similar magnitude occurs
at the same location in two periods, interrupted by a period with very low SPM concentrations. The ETM occurring in June–September
is associated with low salinities; its formation is attributed to the interactions between strong southwesterly winds (5.1–5.6ms−1) and wind-induced waves and tidal currents and, dominant easterly river flow at the mouth of the estuary. The ETM occurring
in February–April is associated with high salinity and is conspicuous. The strong NW and SW winds (3.2–3.7ms−1) and wind-driven waves and currents seem to have acted effectively at the mouth of the estuary in developing turbidity maximum.
The impact of sea breeze appears nearly same as that of trade winds and cannot be underestimated in sediment resuspension
and deposition 相似文献
9.
Sudhir Mittal Asha Rani Rohit Mehra V. Balaram M. Satyanarayanan S. S. Sawant 《Journal of the Geological Society of India》2017,90(2):233-238
In the present study, analysis of 238U concentration in 40 drinking water samples collected from different locations of Jodhpur, Nagaur, Bikaner and Jhunjhunu districts of Rajasthan, India has been carried out by using high resolution inductively coupled plasma mass spectroscopy (HR-ICP-MS) technique. The water samples were taken from hand pumps and tube wells having depths ranging from 50 to 800 feet. The measured uranium concentration lies in the range from 0.89 to 166.89 μg l-1 with the mean value of 31.72 μg l-1. The measured uranium content in twelve water samples was found to be higher than the safe limit of 30 μg l-1 as recommended by World Health Organization (WHO, 2011) and US Environmental Protection Agency (USEPA, 2011). Radiological risk calculated in the form of annual effective dose estimated from annual uranium intake ranges from 0.66 to 138.63 μSv y-1 with the mean value of 26.28 μSv y-1. The annual effective dose in two drinking water samples was found to be greater than WHO (2004) recommended level of 100 μSv y-1. Chemical risk calculated in the form of lifetime average daily dose (LAAD) estimated from the water samples varies from 0.02 to 4.57 μg kg-1 d-1 with the mean value of 0.87 μg kg-1 d-1. The lifetime average daily dose (LAAD) of ten drinking water samples was found to be greater than WHO (2011) recommended level of 1 μg kg-1 d-1. The corresponding values of hazard quotient of 48% water samples were found to be greater than unity.A good positive correlation of uranium concentration with total dissolved solids (TDS) and conductance has been observed. However no correlation of uranium concentration with pH was observed. The results revels that uranium concentration in drinking water samples of the study area can cause radiological and chemical threat to the inhabitants. 相似文献
10.
Vikas Duggal Asha Rani Rohit Mehra V. Balaram 《Journal of the Geological Society of India》2017,89(1):77-81
In Shear strength reduction (SSR) technique, the factor of safety (FOS) is defined as the ratio of the material’s actual shear strength to the minimum shear strength required to prevent failure. Failure surface is found automatically through the zones within the material, where applied shear stresses cross the shear strength of the material. In this paper, a review of the technique is discussed in reference to FLAC. A brief background of the approach together with detailed procedure is presented.An attempt is made to exhibit the shear strength dependency of the strain. As stability of the slope is a function of the shear strength, the development of failure strain reflects the potential failure zone of slope. The shear strain developed in the slope increases with reduction in the shear strength and is reflected in the analysis. The concept of failure ratio (Rf) is incorporated in shear strength reduction technique and is demonstrated. Relationships between the critical shear strength reduction ratio and the safety factor are examined. 相似文献