Earthquake-induced built-up damage identification using IRS-P6 data: a comparative study using fuzzy-based classifiers     

Sandeep Singh Sengar  Anil Kumar  Sanjay Kumar Ghosh  Hans Raj Wason 《国际地球制图》2013,28(2):211-225

The 8 October 2005 earthquake caused widespread destruction in both the state of Jammu and Kashmir of India and Northern Pakistan. Due to poor accessibility in the hazardous and difficult mountainous terrain, a proper and comprehensive ground-based survey was not possible. However, with the help of remote sensing data and its analysis techniques, it is feasible to undertake both earthquake-related damage identification and assessment. This study attempts to document and identify built-up damaged (BD) areas using spectral indices taking temporal multispectral images from IRS-P6 LISS-IV. Five spectral indices have been used to identify BD areas using supervised possibilistic c-means (PCM) and noise cluster (NC) classifiers, to analyse the satellite data. The result indicates that Class Based Sensor Independent (CBSI) based Transformed Normalized Difference Vegetation Index (TNDVI) temporal indices provide the best results for identifying BD areas, while Simple Ratio (SR) index gives the best results for built-up undamaged area identification. Further, it observed that PCM classifier performed better in comparison to NC classifier.  相似文献   

Higher dimensional thick domain wall in Lyra geometry     

F. Rahaman  P. Ghosh  S. Shekhar  S. Mal 《Astrophysics and Space Science》2003,286(3-4):373-379

An exact solution is obtained for a thick domain wall in a five dimensional Kaluza-Klein space time within the framework of Lyra geometry. The space time is nonsingular both in its spatial and temporal behavior. It is shown that the domain wall has no particle horizon and the gravitational force due to them is attractive. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Camouflage Detection Using MWIR Hyperspectral Images     

Vinay Kumar  J. K. Ghosh 《Journal of the Indian Society of Remote Sensing》2017,45(1):139-145

Mid Wave Infra Red (MWIR) region of the electromagnetic spectrum is a key region that is exploited for long range infrared reconnaissance and surveillance applications. Detecting enemy targets and being undetectable is the prime requirement of the modern warfare. In the present study MWIR hyperspectral imaging has been exploited for detection of camouflaged targets in the scene. Detection methodology has been developed using unsupervised target detection algorithms (Reed Xiaoli, K-Means and ISODATA). Methodology has been successfully tested in extracting camouflaged targets from the background. Performance results have been compared. The proposed methodology may in future be applied in detection and identification of gases and minerals in the field.  相似文献   

Indicator minerals as guides to base metal sulphide mineralisation in Betul Belt, central India     

Biswajit Ghosh  M. N. Praveen 《Journal of Earth System Science》2008,117(4):521-536

Zn-bearing minerals that act as indicator minerals for base metal sulphide mineralization from the Proterozoic Betul Belt, central India with special emphasis on their genetic significance have been discussed. Sulphide mineralisation is hosted by the felsic volcanic rocks and has similarities with volcanic-hosted massive sulphide deposits in other parts of the world. Synvolcanic hydrothermal alteration is crudely zoned with an inner high Mg-Ca core and an outer wider envelop of Al-Fe rich mineral assemblage. Most of the prospects have strata bound, moderately to steeply dipping, multiple, sub-parallel sheet like ore bodies composed of disseminated and semi-massive to massive ores. Zn-bearing spinel, staurolite, biotite and ilmenite typically occur within the foot-wall alteration zones in close proximity to the sulphide mineralization. Zincian spinel is ubiquitous irrespective of the nature of alteration zone. Zincian staurolite is nearly absent in Mg-Ca alteration zones but commonly present in Al-Fe alteration zone along with zincian ilmenite. Zn-bearing biotite in intimate association with zincian spinel is generally found in Mg-Ca alteration zone and in the transition to Al-Fe alteration zone. Most of these indicator minerals can be considered as products of desulphidation of sphalerite during metamorphism. Mechanisms other than desulphidation like formation of gahnite by overstepping of the zinc saturation limit of biotite during retrogression to chlorite and formation of zincian staurolite at the expense of gahnite is also recorded. Field presence of these minerals has immense significance in exploration in Betul Belt as they occur in close spatial relationship with the sulphide rich zones and therefore act as direct vectors to ore.  相似文献   

Fractal compression of satellite images     

Jayanta Kumar Ghosh  Ankur Singh 《Journal of the Indian Society of Remote Sensing》2008,36(4):299-311

Fractal geometry provides a means for describing and analysing the complexity of various features present in digital images. In this paper, characteristics of Fractal based compression of satellite data have been tested for Indian Remote Sensing (IRS) images (of different bands and resolution). The fidelity and efficiency of the algorithm and its relationship with spatial complexity of images is also evaluated. Results obtained from fractal compression have been compared with popularly used compression methods such as JPEG 2000, WinRar. The effect of bands and pixel resolution on the compression rate has also been examined. The results from this study show that the fractal based compression method provides higher compression rate while maintaining the information content of RS images to a great extent than that of JPEG. This paper also asserts that information loss due to fractal compression is minimal. It may be concluded that fractal technique has many potential advantages for compression of satellite images.  相似文献   

Projections of Extreme Dry and Wet Spells in the 21st Century India Using Stationary and Non-stationary Standardized Precipitation Indices     

Kaustubh Salvi  Subimal Ghosh 《Climatic change》2016,138(3-4):667-680

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Spatial Supermarket Redlining and Neighborhood Vulnerability: A Case Study of Hartford,Connecticut          下载免费PDF全文

Mengyao Zhang  Debarchana Ghosh 《Transactions in GIS》2016,20(1):79-100

The disinclination of chain supermarkets to locate or relocate existing stores from inner city impoverished neighborhoods to affluent suburbs is termed ‘spatial supermarket redlining’. This study attempts to map and understand the effects of potential spatial supermarket redlining on food access in urban disadvantaged neighborhoods of Hartford, Connecticut. Using a combination of statistical and spatial analysis, we first built a Supermarket Redlining Index (SuRI) from five indicators (sales volume, employee count, accepts food coupons from federally assisted programs, and size and population density of the service area) to rank supermarkets in the order of their importance. Second, to understand the effects of supermarket closures in the inner city, a Supermarket Redlining Impact Model (SuRIM) was built with 11 indicators describing both socioeconomic and food access vulnerabilities. The interaction of these vulnerabilities identified neighborhoods that are maximally impacted by spatial supermarket redlining. Results mapped critical areas in the inner city of Hartford where, if a nearby supermarket closed down or relocated to a suburb with limited mitigation efforts to fill the grocery gap, a large number of minority, poor, and disadvantaged residents would experience difficulties to access healthy food, leading to food insecurity or perhaps a food desert. In conclusion we suggest mitigation efforts to reduce this impact of large supermarket closures.  相似文献   

Uranium mineralisation in carbonate rocks from the upper part of Krol formation in Nainital syncline and its significance for uranium exploration in lesser Himalaya     

K. K. Sinha  Dibakar Ghosh  S. D. Rai  M. K. Khandelwal 《Journal of the Geological Society of India》2016,88(3):295-304

Low grade uranium mineralisation associated with phosphorites/ phosphatic sediments and carbonaceous shale has been well established at and/or close to Krol- Tal contact in some of sub-basins of inner Krol belt such as Nigalidhar, Mussoorie and Garhwal synclines in the realm of lesser Himalaya. Unlike the other sub-basins of the belt, though the Nainital syncline is sparsely phosphatic and carbonaceous, carbonate hosted uranium occurrence is reported for the first time from the syncline. The carbonate-hosted uranium occurrences in Krol D of Nainital syncline are of limited extent with values ranging from 200 ppm to 840 ppm eU3O8. Radioactivity is associated with fractured dolostone/ dolomitic limestone and pelloidal limestone. Uranium phases mostly occur in association with carbonaceous, ferruginous matters and clays. However, ultrafine pitchblende grains do occur associated with idiotopic pyrite aggregates suggesting initial trapping of uranium by organic matters present in sediments which later remobilised and precipitated as fine pitchblende. Subsequently, second phase of remobilisation of uranium under oxidising condition gave rise uraniferous goethite, limonite and other iron oxyhydoxides. In contrast to other sub-basins, the Krol-Tal contact in Nainital syncline does not appear to hold any promising phosphate and uranium mineralisation due to less suitable basinal morphology and low Ca/Mg ratio.  相似文献   

Digital image processing of multispectral ASTER imagery for delineation of alteration and related clay minerals in Sakoli belt: Maharashtra – A case study     

Uday Kumar Ghosh  K. K. Naik  M. P. Kesari 《Journal of the Geological Society of India》2016,88(4):464-470

The extraction of spectral signature through remote sensing data in geological studies is very limited in Indian terrain. The present research is an attempt to delineate alteration and associated minerals using high resolution multispectral advanced space borne thermal emission and reflection (ASTER) data in Sakoli volcano-sedimentary sequence. The alteration zones are generally associated with certain types of mineral and mineral aggregates and are localized in the ground that can be mapped remotely using spectral mapping techniques. The band ratio and selective PCT were applied on calibrated ASTER image to extract spectral signature of index mineral. The results showed that high abundance of these minerals within pixels is corresponding to the alteration zones. The field observation, petrography and XRD analysis of the alteration zones confirmed the presence of dominant mineral phases that were identified remotely.  相似文献