Precision rectification of high resolution satellite imagery without ephemeris data     

Saeid Sadeghian  Mohammad Javad Valadan Zoej  Mahmoud Reza Delavar  Ahmad Abootalebi 《International Journal of Applied Earth Observation and Geoinformation》2001,3(4):366

The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetry, Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling. The satellite orbit, position, attitude angles and interior orientation parameters have to be adjusted in the geometrical model to achieve optimal accuracy with the use of a minimum number of Ground Control Points (GCPs). But most high resolution satellite vendors do not intend to publish their sensor models and ephemeris data. There is consequently a need for a range of alternative, practical approaches for extracting accurate 2D and 3D terrain information from HRSI. The flexibility and good accuracy of the alternative models demonstrated with KFA-1000 and the well-known SPOT level 1A images. A block of eight KFA-1000 space photos in two strips with 60% longitudinal overlap and 15% lateral sidelap and SPOT image with rational function, DLT, 2D projective, polynomials, affine, conformal, multiquadric and finite element methods were used in the test. The test areas cover parts of South and West of Iran. Considering the quality of GCPs, the best result was found with the DLT method with a RMSE of 8.44 m for the KFA-1000 space photos.  相似文献   

Modeling the Uncertainty in the Layout of Geological Units by Implicit Boundary Simulation Accounting for a Preexisting Interpretive Geological Model     

Ferrer  Renato  Emery  Xavier  Maleki  Mohammad  Navarro  Felipe 《Natural Resources Research》2021,30(6):4123-4145

Natural Resources Research - An implicit simulation algorithm that uses signed distance functions is proposed to represent subsurface geological configuration while accounting for two sources of...  相似文献   

Sensitivity analysis and accuracy assessment of the land transformation model using cellular automata     

Hossein Shafizadeh-Moghadam  Ali Asghari  Mohammad Taleai  Marco Helbich  Amin Tayyebi 《地理信息系统科学与遥感》2017,54(5):639-656

This study evaluates the effects of cellular automata (CA) with different neighborhood sizes on the predictive performance of the Land Transformation Model (LTM). Landsat images were used to extract urban footprints and the driving forces behind urban growth seen for the metropolitan areas of Tehran and Isfahan in Iran. LTM, which uses a back-propagation neural network, was applied to investigate the relationships between urban growth and the associated drivers, and to create the transition probability map. To simulate urban growth, the following two approaches were implemented: (a) the LTM using a top-down approach for cell allocation grounding on the highest values in the transition probability map and (b) a CA with varying spatial neighborhood sizes. The results show that using the LTM-CA approach increases the accuracy of the simulated land use maps when compared with the use of the LTM top-down approach. In particular, the LTM-CA with a 7 × 7 neighborhood size performed well and improved the accuracy. The level of agreement between simulated and actual urban growth increased from 58% to 61% for Tehran and from 39% to 43% for Isfahan. In conclusion, even though the LTM-CA outperforms the LTM with a top-down approach, more studies have to be carried out within other geographical settings to better evaluate the effect of CA on the allocation phase of the urban growth simulation.  相似文献   

Context-awareness in similarity measures and pattern discoveries of trajectories: a context-based dynamic time warping method     

Mohammad Sharif 《地理信息系统科学与遥感》2017,54(3):426-452

Analyzing the spatial behaviors of moving-point objects (MPOs) and discovering their movement patterns have been of great interest to the geographic information science community recently. These interests can be explored through analyzing similarities in the MPO trajectories. Because movements of objects take place in various contexts, their trajectories are also highly influenced by such contexts. Therefore, it is essential to fully understand the contexts and to realize how they can be incorporated into movement analysis. This article first proposes a taxonomy for contexts. Then, a modified version of dynamic time warping called context-based dynamic time warping (CDTW) is introduced, to contextually assess the multidimensional weighted similarities of trajectories. Ultimately, the results of similarity searches are utilized in discovering the relative movement patterns of the MPOs. To evaluate the performance and effectiveness of our proposed CDTW method, we run several experiments on real datasets that were obtained from commercial airplanes in a constrained Euclidean space, taking into account contextual information. Specifically, these experiments were conducted to explore the role of contexts and their interactions in similarity measures of trajectories. The results yielded the robustness of CDTW method in quantifying the commonalities of trajectories and discovering movement patterns with 80% accuracy. Moreover, the results revealed the importance of exploiting contextual information because it can enhance and restrict movements.  相似文献   

Climatology of diurnal tide and its long-term variability in the lower middle atmosphere over a tropical station     

P.?Vinay?Kumar  Gopa?DuttaEmail author  Salauddin?Mohammad  B.?Venkateswara?Rao 《Theoretical and Applied Climatology》2017,130(1-2):151-162

ECMWF reanalysis (ERA–interim) data of winds for two solar cycles (1991–2012) are harmonically analyzed to delineate the characteristics and variability of diurnal tide over a tropical site (13.5° N, 79.5° E). The diurnal cycle horizontal winds measured by Gadanki (13.5° N, 79.2° E) mesosphere–stratosphere–troposphere (MST) radar between May 2005 and April 2006 have been used to compute 24 h tidal amplitudes and phases and compared with the corresponding results obtained from ERA winds. The climatological diurnal tidal amplitudes and phases have been estimated from surface to ～33 km using ERA interim data. The amplitudes and phases obtained in the present study are found to compare reasonably well with Global Scale Wave Model (GSWM–09). Diurnal tides show larger amplitudes in the lower troposphere below 5 km during summer and in the mid-stratosphere mainly during equinoctial months and early winter. Water vapor and convection in the lower troposphere are observed to play major roles in exciting 24-h tide. Correlations between diurnal amplitude and integrated water vapor and between diurnal amplitude and outgoing longwave radiation (OLR) are 0.59 and ?0.34, respectively. Ozone mixing ratio correlates (ρ?=?0.66) well with diurnal amplitude and shows annual variation in the troposphere whereas semi-annual variation is observed at stratospheric heights with stronger peaks in equinoctial months. A clear annual variation of diurnal amplitude is displayed in the troposphere and interannual variability becomes prominent in the stratosphere which could be partly due to the influence of equatorial stratospheric QBO. The influence of solar activity on diurnal oscillations is found to be insignificant.  相似文献   

Mineralogy and distribution of Platinum-Group Minerals (PGM) and other solid inclusions in the Faryab ophiolitic chromitites, Southern Iran     

Mohammad Ali Rajabzadeh  Zohreh Moosavinasab 《Mineralogy and Petrology》2013,107(6):943-962

High-Cr podiform chromitites hosted by upper mantle depleted harzburgite were investigated for PGM and other solid inclusions from Faryab ophiolitic complex, southern Iran. Chemical composition of the chromian spinels, Cr#[100*Cr/(Cr+Al) = 77–85], Mg# [100*Mg/(Mg+Fe²⁺) = 56–73], TiO₂≤0.25wt%, and the presence of abundant primary hydrosilicates included in the chromian spinels indicate that the deposits were formed from aqueous melt generated by high degree of partial melting in a suprasubduction zone setting. Solid phases hosted by chromian spinel grains from the Faryab ophiolitic chromitites can be divided into three categories: PGM, base-metal minerals and silicates. Most of the studied PGM occurred as very small (generally less than 20 μm in size) primary single or composite inclusions of IPGE-bearing phases with or without silicates and base metal minerals. The PGM were divided into the three subgroups: sulfides, alloys and sulfarsenides. Spinel-olivine geothermometry gives the temperatures 1,131–1,177 °C for the formation of the studied chromitites. At those temperatures, fS₂ values ranged from 10^?3 to 10^?1 and provided a suitable condition for Ru-rich laurite formation in equilibrium with Os-Ir alloys. Progressive crystallization of chromian spinel was accompanied by increase of fS₂ in the melt. The formation of Os-rich laurite, erlichmanite and then sulfarsenides occurred by increase of fS₂ and slight decrease in temperature of the milieu. The compositional and mineralogical determinations of PGM inclusions respect to their spatial distribution in chromian spinels show that the minerals regularly distributed within the chromitites, reflecting cryptic variation consistent with magmatic evolution during host chromian spinel crystallization.  相似文献   

Geomorphological investigation of possible impact evidences for the crater-shaped structure of Zirouki in Samsour Desert, SE Iran     

Mohammad Reza Mansouri Daneshvar  Ali Bagherzadeh 《Earth Science Informatics》2013,6(4):241-252

Despite the extensive records on geomorphological studies in Iran, meteorite impact craters have so far not been considered in to account. Based on both remote sensing technique and field work we have recognized the circular structure of Zirouki crater in the Samsour desert, southeast of Iran, which if confirmed as an impact structure, would be the third impact structure candidate in the Middle East after the Wabar craters in Saudia Arabia and Jebel Waqf as Suwwan in Jordan. Geomorphological investigation of the possible impact structure of Zirouki crater was done based on multi criteria methodology including of geological, topographical, geophysical and petrographical studies. Among different studies, topographical investigation indicated that the crater shape morphology was quite obvious with a central uplift projection; as well geophysical pattern provided very strong evidence for possible impact structure, indicating the presence of circular negative gravity anomaly at the whole of the crater.  相似文献   

Groundwater arsenic contamination in Ganga–Meghna–Brahmaputra plain, its health effects and an approach for mitigation     

Dipankar Chakraborti  Mohammad Mahmudur Rahman  Bhaskar Das  Bishwajit Nayak  Arup Pal  Mrinal Kumar Sengupta  Md. Amir Hossain  Sad Ahamed  Manabendranath Sahu  Kshitish Chandra Saha  Subhash Chandra Mukherjee  Shyamapada Pati  Rathindra Nath Dutta  Quazi Quamruzzaman 《Environmental Earth Sciences》2013,70(5):1993-2008

The authors’ survey of the Ganga–Meghna–Brahmaputra (GMB) plain (area 569,749 km²; population >500 million) over the past 20 years and analysis of more than 220,000 hand tube-well water samples revealed groundwater arsenic contamination in the floodplains of the Ganga–Brahmaputra river (Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Assam) in India and the Padma–Meghna–Brahmaputra river in Bangladesh. On average, 50 % of the water samples contain arsenic above the World Health Organization guideline value of 10 μg/L in India and Bangladesh. More than 100 million people in the GMB plain are potentially at risk. The authors’ medical team screened around 155,000 people from the affected villages and registered 16,000 patients with different types of arsenical skin lesions. Arsenic neuropathy and adverse pregnancy outcomes have been recorded. Infants and children drinking arsenic-contaminated water are believed to be at high risk. About 45,000 biological samples analyzed from arsenic-affected villages of the GMB plain revealed an elevated level of arsenic present in patients as well as non-patients, indicating that many are sub-clinically affected. In West Bengal and Bangladesh, there are huge surface water in rivers, wetlands, and flooded river basins. In the arsenic-affected GMB plain, the crisis is not over water scarcity but about managing the available water resources.  相似文献   

Prediction of drought in dry lands through feedforward artificial neural network abilities     

Hossein Bari Abarghouei  Mohammad Reza Kousari  Mohammad Amin Asadi Zarch 《Arabian Journal of Geosciences》2013,6(5):1417-1433

Drought is one of the most important natural hazards in Iran. It is especially more prevalent in arid and hyper arid regions where there are serious limitations in regard to providing sufficient water resources. On the other hand, drought modeling and particularly its prediction can play important role in water resources management under conditions of lack of sufficient water resources. Therefore, in this study, drought prediction in a hyper arid location of Iran (Ardakan region) has been surveyed based on the abilities of artificial neural. Standardized Precipitation Index (SPI) in different time scales (3, 6, 9, 12, and 24 monthly time series) computed based on the data gathered from four rain gauge stations. After evaluation and testing of different artificial neural networks (ANN) structures, gradient descent back propagation (traingd) network showed higher abilities than others. Then, the predictions of SPI time series with different monthly lag times (1:12 months) were tested. Generally, drought prediction by ANNs in the Ardakan region has shown considerable results with the correlation coefficient (R) more than 0.79 and in the most cases and it rises more than 0.90, which indicates the ANN’s ability of drought prediction.  相似文献   

Determination of optimum relaxation coefficient using finite difference method for groundwater flow     

Farzin Salmasi  Hazi Mohammad Azamathulla 《Arabian Journal of Geosciences》2013,6(9):3409-3415

Solution of Laplace’s equation can be done by iteration methods likes Jacobi, Gauss–Seidel, and successive over-relaxation (SOR). There is no new knowledge about the relaxation coefficient (ω) in SOR method. In this paper, we used SOR for solving Laplace’s differential equation with emphasis to obtaining the optimum (minimum) number of iterations with variations of the relaxation coefficient (ω). For this purpose, a code in FORTRAN language has been written to show the solution of a set of equations and its number of iterations. The results demonstrate that the optimum value of ω with minimum iterations is achieved between 1.7 and 1.9. Also, with increasing β?=??x/?y from 0.25 to 10, the number of iterations reduced and the optimum value is obtained for β?=?2.  相似文献