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181.
182.
Chamundeeswari V.V. Singh D. Singh K. 《Geoscience and Remote Sensing Letters, IEEE》2009,6(2):214-218
In single-band single-polarized SAR images, intensity and texture are the information source available for unsupervised land cover classification. Every textural feature measure identifies texture patterns by different approaches. For efficient land cover classification, textural measures have to be chosen suitably. Therefore, in this letter, the role of various intensity and textural measures is analyzed for their discriminative ability for unsupervised SAR image classification into various land cover types like water, urban, and vegetation areas. To make the algorithm adaptable, these textural features are fused using principal component analysis (PCA), and principal components are used for classification purposes. To highlight the effectiveness of PCA, the difference between PCA- and non-PCA-based classifications is also analyzed. Analysis of the role of texture measures for unsupervised classification of real-world SAR data with application of PCA is presented in this letter. The analysis of how every individual feature measure contributes for classification process is presented, and then, textural measures for a feature set are chosen according to their role in improving classification accuracy. By analysis, it is observed that the feature set comprising mean, variance, wavelet components, semivariogram, lacunarity, and weighted rank fill ratio provides good classification accuracy of up to 90.4% than by using individual textural measures, and this increased accuracy justifies the complexity involved in the process. 相似文献
183.
Planning based on agro-ecological zoning aims at scientific management of regional resources to meet the food, fibre, fodder
and fuel wood requirements without adversely affecting the status of natural resources and environment. An attempt has been
made to map the agro-ecological units for Vellore district of Tamil Nadu and derive the crop-zone map for the four major crops
namely, paddy, sugarcane, groundnut and millets. The basic theory of FAO framework for Land Evaluation was adopted to define
the suitability of crops. Land quality details necessary for evaluating the agro-land suitability of crops and for delineating
the agroecological units include the terrain, soil and climatic characteristics. Agro-ecological units map was generated by
overlaying the agro-edaphic and agroclimatic map layers in GIS. The agro-land suitability map was generated by matching the
crop requirement details with the land qualities. The results of the suitability evaluation, when compared with the current
land use statistics of these crops showed that area cultivated is less than the area suitable for these crops. 相似文献
184.
K. Chakraborty P. K. Joshi K. K. Sarma 《Journal of the Indian Society of Remote Sensing》2009,37(1):99-106
Meghalaya is a landlocked state where the progress of industrialization is very slow. Majority of the population (rural) depends
on agriculture. Agriculture in the state is carried on in primitive ways with Jhumming prevailing in many parts. This practice is considered destructive as vast forest areas are cleared and burnt. Such areas
are used for cultivation and left out. After a gap of few years (2–3 years as of now and 15–20 years in past) the area is
revisited for cultivation without allowing to rejuvenate. The present work provides a status and trend of Land use land cover
dynamics in parts (at watershed level) of Meghalaya. The geospatial tools have been used to assess (a) the changes in land
use land cover since 1970s to 2005; (b) patch dynamics for understanding the degree of fragmentation; (c) changes along the
terrain topography. Umngot watershed of Meghalaya is taken as experimental area, which is a representative of mid-altitudinal
watershed particularly in the Jaintia hills district of Meghalaya. 相似文献
185.
The purpose of this paper is the canonical connection of classical global gravity field determination following the concept of Stokes (Trans Camb Philos Soc 8:672–712, 1849), Bruns (Die Figur der Erde, Publikation Königl. Preussisch. Geodätisches Institut, P. Stankiewicz Buchdruckerei, Berlin, 1878), and Neumann (Vorlesungen über die Theorie des Potentials und der Kugelfunktionen. Teubner, Leipzig, pp 135–154, 1887) on the one hand and modern locally oriented multiscale computation by use of adaptive locally supported wavelets on the other hand. The essential tools are regularization methods of the Green, Neumann, and Stokes integral representations. The multiscale approximation is guaranteed simply as linear difference scheme by use of Green, Neumann, and Stokes wavelets. As an application, gravity anomalies caused by plumes are investigated for the Hawaiian and Iceland areas. 相似文献
186.
Long term shoreline oscillation and changes of Cauvery delta coastline inferred from satellite imageries 总被引:2,自引:0,他引:2
R. Sathyanarayan Sridhar K. Elangovan P. K. Suresh 《Journal of the Indian Society of Remote Sensing》2009,37(1):79-88
Coastal zone is highly volatile ecosystem which is always in adjustments. Loss of shore line will cause severe impact on human
life and as well as their properties. Remote sensing is a reliable technique to study the historical shoreline changes. Therefore
in this paper long term shoreline oscillations of Cauvery delta shorelines at Poompuhar, Tharangambadi and Nagapattinam were
studied using satellite imageries and the same was physically observed at the above three locations with the help of reference
pillars and compared mutually. It was observed that the shoreline at Poompuhar is under accretion at the rate of 1.79m/ year
and other shoreline stretches at Tharangambadi and Nagapattinam were under erosion at 0.4888m/ year and 0.4985m/ year respectively.
It was also observed that the remote sensing study qualitatively matches with the physical observation for all the three coastal
stretches of the study area. 相似文献
187.
Reshu Agarwal Rakesh Gupta J. K. Garg 《Journal of the Indian Society of Remote Sensing》2009,37(3):473-481
A three-step hierarchical Semi Automated Empirical Methane Emission Model (SEMEM) has been used to estimate methane emission
from wetlands and waterlogged areas in India using Moderate Resolution Imagine Spectroradiometer (MODIS) sensor data onboard
Terra satellite. Wetland Surface Temperature (WST), methane emission fluxes and wetland extent have been incorporated as parameters
in order to model the methane emission. Analysis of monthly MODIS data covering the whole of India from November 2004 to April
2006 was carried out and monthly methane emissions have been estimated. Interpolation techniques were adopted to fill the
data gaps due to cloudy conditions during the monsoon period. AutoRegressive Integrated Moving Average (ARIMA) model has been
fitted to estimate the emitted methane for the months of May 2006 to August 2006 using SPSS software. 相似文献
188.
Arun K. Saraf Vineeta Rawat Swapnamita Choudhury Sudipta Dasgupta Josodhir Das 《International Journal of Applied Earth Observation and Geoinformation》2009
Stresses building up during an earthquake preparation phase also manifest themselves in the form of a so called increased land surface temperature (LST) leading to a thermal precursor prior to the earthquake event. This phenomenon has now been validated by our observations of short-term thermal anomalies detected by infrared satellite sensors for several recent past earthquakes around the world. The rise in infrared radiance temperature was seen to vary between 5 and 12 °C for different earthquakes. We discuss in this paper different explanations for the generation of such anomalies that have been offered. Emission of gases due to the opening and closure of micropores upon induced stresses and also the participation of ground water have been propounded as a possible cause for generation of thermal anomalies. Seismo-ionosphere coupling, by which gases like radon move to the earth–atmosphere interface and cause air ionization thus bringing about a change in air temperature, relative humidity, etc., has been put forth by some workers. A mechanism of low frequency electromagnetic emission was tested and experimented by scientists with rock masses in stressed conditions as those that exist at tectonic locations. The workers proposed the positive hole pair theory, which received support from several scientific groups. Positive holes (sites of electron deficiency) are activated in stressed rocks from pre-existing yet dormant positive hole pairs (PHPs) and their recombination at rock–air interface leads to a LST rise. A combination of remote sensing detection of rock mechanics behavior with a perception of chemistry and geophysics has been applied to propose the remote sensing rock mechanics theory. Remote sensing detections of such anomalies confirm so far proposed lab theories for such a hotly debated field as earthquake precursor study by providing unbiased observations with consistency in time and space distribution. 相似文献
189.
Ben K. H. Soon Steve Scheding Hyung-Kuen Lee Hung-Kyu Lee Hugh Durrant-Whyte 《GPS Solutions》2008,12(4):261-271
This paper presents a simple and effective approach that incorporates single-frequency, L1 time-differenced GPS carrier phase
(TDCP) measurements without the need of ambiguity resolution techniques and the complexity to accommodate the delayed-state
terms. Static trial results are included to illustrate the stochastic characteristics and effectiveness of the TDCP measurements
in controlling position error growth. The formulation of the TDCP observation model is also described in a 17-state tightly-coupled
GPS/INS iterative, extended Kalman filter (IEKF) approach. Preliminary land vehicle trial results are also presented to illustrate
the effectiveness of the TDCP which provides sub-meter positional accuracies when operating for more than 10 min. 相似文献
190.
K. N. Prudhvi Raju Sarvajeet Kumar Kshitij Mohan Manish Kumar Pandey 《Journal of the Indian Society of Remote Sensing》2008,36(3):283-288
With growing urban expanses, one of the pre-requisites for effective governance is Urban Information Systems (UIS) with content
down to individual properties (and individuals). The basic input i.e., a map, in UIS should show individual property boundaries
showing the plan outline of all structures existing within, at a scale of 1:1000 and larger with sub-metre to centimeters
planimetric and geometric accuracy. With very high resolution remote sensing data of the order of 1m available in hand, it
is possible to prepare maps with high resolution spatial content. The present exercise demonstrates a method of preparing
a geometrically and planimetrically accurate urban cadastral map on very large scale for a small area of about 5 sq km. IKONOS
merged data with 1m resolution is used for the purpose. Mapping was done in conjunction with on-site measurements and sketches.
Guides are used to maintain shape symmetry and accuracy of buildings and other features. Working out cost of mapping per unit
area is another objective in the present exercise. For want of fully or semi-automatic methods of information extraction from
very high resolution remote sensing data, it is imperative that mapping should be carried out in conjunction with some on-site
measurements wherever necessary. 相似文献