Extraction and validation of cartosat-1 DEM     

Nadeem Ahmed  Anjum Mahtab  Ritesh Agrawal  P. Jayaprasad  S. K. Pathan  Ajai  D. K. Singh  A. K. Singh 《Journal of the Indian Society of Remote Sensing》2007,35(2):121-127

CARTOSAT-1 satellite, launched in May, 2005 is a dedicated along track stereo mission providing high quality data for topographic and cartographic applications. The present paper describes the evaluation of the Cartosat-1 stereo data, mainly through the generation and validation of DEM for moderately undulating and hilly areas. Photogrammetric techniques have been used for generation of DEM and Orthoimage for two cases i.e. 1) using RPCs (Rational Polynomial Coefficients) and 2) using RPCs along with ground control points. Root Mean Square Error (RMSE) in elevation values for the moderately undulating (Dehradun) and hilly area (Shimla), are found to be 4.38 and 3.69m respectively.  相似文献   

Observation of soft X-ray emission from a region near Per X-1     

P. C. Agrawal  K. Long  G. P. Garmire 《Astrophysics and Space Science》1974,28(1):185-191

Soft X-ray emission from the X-ray source Per X-1 was observed in the 0.4–2 keV energy interval from a rocket borne X-ray detector. Spectral analysis of the data indicates that in the 0.4–2 keV band the X-ray emission from Per X-1 can be fitted either with a power law of slope-(4.8±1.2) or a thermal bremsstrahlung spectrum with akT value of (0.26 _?0.08 ^+0.12 ) keV. Such a steep spectrum is inconsistent with the spectrum measured above 2 keV. The measured flux in 0.4–2 keV band corresponds to X-ray luminosity of 3×10⁴⁵ ergs s^?1 for Per X-1.  相似文献   

Heat transfer in unsteady MHD couette flow of an electrically conducting,viscous, incompressible rarefied gas     

H. L. Agrawal  R. Nath  R. P. Singh 《Astrophysics and Space Science》1987,129(1):169-180

An analytical study is performed to examine the heat transfer characteristics on the flow of a viscous, incompressible rarefied gas in a parallel plate channel under the action of transverse magnetic field when (i) suction velocity normal to the plate is constant, (ii) the second plate oscillates in time about a constant non-zero mean, (iii) fluid is subjected to a constant heat source of absorption type. Apprximate solutions for velocity, temperature, phase, and amplitude of skin-friction and rate of heat transfer are evaluated. Mean temperature profiles, phase and amplitude of rate of heat transfer at both plates are discussed graphically followed by a quantitative discussion. Mean rate of heat transfer is tabulated in Table I.  相似文献   

Diffusion of rare gases of solar wind origin from lunar fines as bubbles     

A.S. Tamhane  J.K. Agrawal 《Earth and Planetary Science Letters》1979,42(2):243-250

A diffusion mechanism is proposed which takes into account phenomena observed in ion-implanted solids, in particular the precipitation of rare gas in the form of bubbles and their migration. The composition of rare gases in the bubbles is inferred from the calculated distribution of solar wind rare gas ions as a function of depth in the grains. These calculations are made for the location and average composition of Apollo 11 samples. It is shown by analogy with experimental observations in ion-implanted solids that the bubbles would migrate towards the surface and that the diffusion constant for this migration would be strongly depth dependent. Relative abundances of rare gas nuclides remaining behind due to the resultant degassing are estimated for one Apollo 11 soil sample and are compared with observed relative abundances for this sample. A qualitative explanation of some of the experimental observations of Ducati et al. on individual lunar grains is also offered.  相似文献   

Cogeneticity of Tavidar volcanics: Evidence by mixing line calculation     

Vinod Agrawal  Rajani Upadhyaya 《Mathematical Geology》1991,23(1):47-52

The Tavidar volcanics belong to a trachybasalt-trachyandesite-rhyolite association. Distribution and behavior of major and trace elements and field relationships indicate that intermediate and acidic volcanics of the area are cogenetic, whereas the basaltic phase is younger. Cogeneticity also is confirmed by the mixing line calculation. In the present case, instead of two pole mixing, three pole mixing between end members andesite, quartztrachyte, and rhyolite has been considered. Results show that a perfect linearity in data exists between andesites and quartztrachyte and between quartztrachyte and rhyolites.  相似文献   

Meeting reports     

R. C. Agrawal  Yves Gratton 《Natural Hazards》1990,3(1):91-94

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Utilization of remotely sensed data for soil resource mapping and its interpretation for landuse planning of Bhiwani district,Haryana     

R L Ahuja  M L Manchanda  B S Sangwan  V P Goyal  R P Agrawal 《Journal of the Indian Society of Remote Sensing》1992,20(2-3):105-120

Visual interpretation of IRS-1A LISS-II (October 1988 & Feb. 1989) FCC (spectral bands 2, 3 & 4) at 1:50,000 scale was carried out for soil resource mapping of Bhiwani district (Haryana State) covering on area of 5099 sq. kim. Based on image characteristics, element analysis (landform, vegetation & erosion) and field traverses, physiography-soil relationship was established. Major physiographic units identified in the area are: Aeolian plain, Fluvio-acolian plain, Transitional plain, Alluvial plain, Hills and Pediments. Area was divided into 34 subunits. Final physiography-soil map on 1:50,000 scale was prepared. Taxonomically, the soils of each unit were classified and are found as: In aeolian plain—Typic Torripsamments/coarse loamy, Typic Camborthios; Fluvio-aeolian plain-Aridic Ustipsamments/coarse loamy/fine loamy Typic/Udic Ustochrepts; Alluvial plain—Typic Ustipsamments/coarse loamy/fine loamy Typic/Udic Ustochrepts; Hills and Pediments—fregmental Lithic Torriorthents/Typic Torripsamments. Interpretation for each subunit was made regarding land suitability for various land utilisation types. It was found that hills and pediments, dunal ridges, dunal complexes and serub-lands are best suitable for forestry and horiculture plantations. Dunal plains and inter-dunal depressions are best suitable for gram/bajra/oilseeds/guar, very gently sloping dunal plain and low lying plain are suitable for wheat/arhar/cotton/sunflower.  相似文献   

The Neogene/Quaternary boundary in India: A review     

D P Agrawal  D K Bhatt  Sheela Kusumgar  R K Pant 《Journal of Earth System Science》1981,90(2):111-123

The Neogene/Quaternary boundary has been variously defined in different continents. A global review of the problem shows that only the Olduvai event on the palaeomagnetic timescale may provide an universally acceptable isochronous datum for delineating this boundary. The N/Q boundary in the Siwaliks, Kashmir and the Andamans in India is defined in the light of recent research.  相似文献   

A rapid method of trace analysis of uranium(VI) from phosphorites     

R.K. Dubey  Y.K. Agrawal 《Chemical Geology》1975,15(3):223-227

A new spectrophotometric method for the microdetermination of uranium(VI) from phosphorites in the presence of commonly occurring metal ions has been developed. Uranium is extracted from chloroform solution of N-phenyl-2-naphtho-hydroxamic acid (N-P-2-NHA) at pH 4.0–4.5. The orange-red extract has the maximum absorption at 515 nm. The extraction was quantitative and obeys Beer's law at 515 nm.  相似文献   

A Platform for Visualizing and Experimenting with Measures of Semantic Similarity in Ontologies and Concept Maps     

Mark Gahegan  Ritesh Agrawal  Anuj Jaiswal  Junyan Luo  Kean‐Huat Soon 《Transactions in GIS》2008,12(6):713-732

This article describes research in the ongoing search for better semantic similarity tools: such methods are important when attempting to reconcile or integrate knowledge, or knowledge‐related resources such as ontologies and database schemas. We describe an extensible, open platform for experimenting with different measures of similarity for ontologies and concept maps. The platform is based around three different types of similarity, that we ground in cognitive principles and provide a taxonomy and structure by which new similarity methods can be integrated and used. The platform supports a variety of specific similarity methods, to which researchers can add others of their own. It also provides flexible ways to combine the results from multiple methods, and some graphic tools for visualizing and communicating multi‐part similarity scores. Details of the system, which forms part of the ConceptVista open codebase, are described, along with associated details of the interfaces by which users can add new methods, choose which methods are used and select how multiple similarity scores are aggregated. We offer this as a community resource, since many similarity methods have been proposed but there is still much confusion about which one(s) might work well for different geographical problems; hence a test environment that all can access and extend would seem to be of practical use. We also provide some examples of the platform in use.  相似文献