نشریه مهندسی نقشه برداری و اطلاعات مکانی
سال پنجم شماره 2 (پیاپی 18، خرداد 1393)

Damavand volcano with a height of over 5670 meters is a unique phenomenon that is based on the Central Alborz. Accordance with the international division of volcanology، volcanoes، with less than 10،000 years old «potentially active volcano eruption risk» is considered. Thus، Damavand is an active volcano. In this study due to the possible eruption and using the intrinsic geometry، the geodynamic situation in Central Alborz is discussed. It uses the GPS data of the Geodynamic Network of Iran in 2006 and 2007. The values of dilatation and maximum shear and changes of mean and Gaussian curvatures of this area were computed. Dilatation and maximum shear values of the order of 10 3 are obtained. Maximum of the Gaussian and mean curvature were 2. 6 × 10-22 and 5. 3 × 10-11، respectively that results indicate that subsidence in the central Alborz. InSAR observations of the region confirm the results.

Any knowledge of a fault motions and its effects such as gravity field changes is the main reason of this research. After large earthquakes some deformations occur in the Earth’s crust. It’s important to note that as a result of an earthquake whole of the Earth and not just it’s surface is deformed. Since displacement field causes mass redistribution so gravity field and geoid height change after an earthquake. In this research، the general method of different gravity field component changes due to an earthquake in a fault with an arbitrary geometry and slip is investigated. For this purpose Green function method for blind fault in an elastic half space is used and analytical closed functions for coseismic gravity changes due to a plane dislocation is introduced. Combination of obtained results of modeling and observed gravity change we can use it as a tool for geometry determination of a dislocation or geoid height change in the area of earthquake occurrence. Simulation results shows that a large earthquake can change the geoid height upto one meter. The 2012/8/11، Mw = 6. 5 and Mw = 6. 3 dual earthquakes of Varzagan and Ahar in East Azerbaijan Province of NW Iran is examined and gravity changes due to these earthquakes is estimated. Computation results show that gravity field changes due to an earthquake is more than the instrumental precision. It’s important to note that this model could be implemented for any other fault in the study area with an arbitrary geometry properties and gravity field changes could be estimated for any point. For the first event Mw = 6. 5 of Ahar-Varzagan dual earthquakes total gravity changes is in the range of -10. 929 microgal to 10. 257 microgal. Also for the second one Mw = 6. 3 this range is from -43. 977 microgal to 16. 545 microgal. Obtained results show that gravity field changes for a strike slip fault is less than dip slip or tensile faults.

Modeling of gravity field has many application in geosciences such as geodesy، geophysics، and oceanography and tectonic. Marine Gravity observations due to factor such as oscillation and accelerations of ship، also mechanical errors that are greater in water have low precision. Satellite altimetry provide detailed information about geoid changes and its slope changes over the oceans. in geodesy we can convert geoid and its slope (deflection of vertical component)، to gravity anomaly using spectral analysis methods. There are two integral equation to estimate gravity anomaly from geoid and deflection of vertical، stokes integral and vening meinesz integral. In this paper method of marine gravity anomaly deriving from satellite altimetry are introduced and then using satellite altimetry data estimate marine gravity anomaly over Oman Sea that is a Deep region. Then for control precision of methods، use marine gravity anomaly points that have corrected and collected by national geophysical data center (NGDC). our result show that in gravity anomaly estimation from satellite altimetry using Deflections of vertical as observation and spectral kind of vening meinesz integral as method have a RMS of 4. 2 mgal in comparison with shipborne data، while the using geoid as observation and spectral kind of stokes integral as method، have 4. 38 mgal in comparison with shipborne data. This indicate spectral kind of vening meinesz integral have advantage in comparison with spectral kind of stokes integral.

Create، maintain and development of public transport network in metropolitan are important problems in the field of urban transport management. In public transport، maximize the efficient use of public fleet capacity has been considered. Concepts and technologies of GIS have provided suitable way for management and optimization of the public transports systems. In demand-responsive public transportation system، firstly fellow traveller groups have been established for applicants based on spatial concepts and tools of GIS، second for each group according to its’ members and their paths، a public vehicle has been allocated to them then based on dynamic routing، the fellow traveller group has been gathered from their origin and has been moved to their destination through optimal route. The suggested system has been implemented based on network data and commuting trips statistics of 1 to 6 districts in Tehran city. Evaluation performed on the results show the 34% increase using of Taxi capacity، 13% increase using of Van capacity and 10% increase using of Bus capacity in comparison between current public transport system and suggested public transportation system has been improved.

The issue of water quantity and quality، by itself and without any untimely accident or natural disaster or a crisis، is considered as a major challenge. This crisis and its effects، particularly for our disaster-prone country will be very disastrous exchange and its risk management would be more critical. Today along the very sharp improvement in technologies such as GIS and other helpful related instruments like GPS، the necessity of establishing، developing and applying databases upon spatial information in order to get ready، prevent، and manage the conflicts and crisis in emergencies would be a very useful decision support system and with no doubt، tomorrow is too late. In order to fulfill the purposes of this strategy and policy، investment in this field and teaching experts، providing hardware and software and the most important factor via paving administrative culture and field and its path in order to help the entrance and applying of this useful technology would help us in crucial and emergency situations. These affaires especially for water and sewage organizations due to their heavy، risky and vital responsibilities to provide the people with healthy water and transport waste water are of high necessity. Providing these organizations that support the vital networks of life like water network، power، gas، communication and transportation system with these basis، in addition to fulfill their daily needs and administrative responsibilities can also reduce the risk of any crisis and disaster. The results can also be used as a Spatial Decision Support System (SDSS) and also can provide National Spatial Data Infrastructures (NSDI) with worthy data and information to help the sustainable development. In order to fulfill the purposes of this study، feasibility study and conceptual، logical and physical models of establishing water database was performed in water and wastewater organization of Alborz province and a network based and user friendly software designed according to the needs of different sections of organization and finally some GPSs were installed on some vehicles that with using the related database helps us in monitoring، controlling and optimum management of the emergency vehicles in crisis situations and in route finding، gathering data and optimum crisis management as well.

Collecting surface water and organizing them is important issue in urban management. It is more important when rainfall caused flood streets. In this conditions، the waterways and canals network of guide and Transfer of surface water، according to water flow rate and capacity، aren’t able to control and convey surface water. As a result، many problems can arise with water overflow and passageways Flooded. Many studies have been done in this field، that represent strategy for managing urban runoff Based calculation the flow accumulation is An important part of their. Therefore، the design and implementation of a spatial and temporal system that can simulating rainfall conditions for the prediction and management of such problems can be very useful. One of the technologies in this field can be a highly efficient، is using of agent based simulation systems. The two factors of time and place are able modeling and studied together in agent based systems. In agent based modeling with using parts influence can be achieved to overall results. Thus، by using the agent-based modeling can be designed and implemented a system to manage surface water. By results of this study، areas at risk can be predicted and identify and necessary decisions be taken to deal with the crisis.

In this letter we develop a target detection method using high-resolution radar images based on constant false alarm rate (CFAR) algorithm. CA-CFAR، the specific CFAR algorithm utilized in this paper، is a CFAR method with high performance and easy implementation used in many studies providing good results. This adaptive algorithm assigns a pixel as a target pixel by comparing the pixel intensity with a threshold calculated from surrounding pixels of the pixel under test. Experimental results show that the algorithm provides best results with lowest false alarm using the “span” image that contains more polarimetric information as compared to the single channel data. RADARSAT-2 polarimetric SAR data acquired over the San Francisco city has been chosen to assess the capability of the proposed approach. The coherency matrix data is extracted from this dataset and the proposed approach is performed on single band images corresponding to different polarimetric channel and the span image as a compound of all the single polarization images.

Due to the growing cities، urban planning in the context of growing suburbanization، legal and illegal construction in urban is necessary. High-resolution stereo images that have been taken in two different times and the three-dimensional urban database، can help to building change detection. This research has been used to capability of stereo image to DSM generation and applying the difference digital surface model (D-DSM) in two periods، by using the image processing methods، Also according to existence of urban database and having geometric properties such as shape، size and height of urban features and applying the morphological filters، We attempted to D-DSM refinement and the elimination of non-Building features and the features extracted from this phase، as the building has been approved and will be reviewed to assess changes. With the evaluation results of D-DSM and set the suitable threshold، the buildings can be divided into three categories، unchanged، modified and the vague. After determining the vague things that can be done semi-automatically، the building change map provide and urban database be updated. In this study، we reached to 89. 0% completeness and 80. 8% correctness in semi-urban areas and 83. 9% completeness and 78. 2%correctness in urban areas. By examining the elevation of results was extracted، it can be divided the buildings to three categories: new Building، Reconstructed building and building with height changes (adding floor).

The purpose of this study is the assessment of polarimetric SAR and hyperspectral images for concealed target detection in forest areas. In fact، this paper is an introduction to fusion the two data in a target detection algorithm. The proposed method is using the polarimetric and the spectral signatures. A RADARSAT-2 image and a Hyperion image of the city San Francisco were chosen for evaluation of the proposed method. The four targets were selected in the forest and the outer areas. Three pattern recognition methods included SCM، SAM، and ED were used to determine the matching rate between the two signatures. Results reported the SAM and SCM matching methods، have a better performance than ED in polarimetric signatures. In addition، the SAM and ED have a better performance than SCM in spectral signatures. As the results polarimetric SAR data detect concealed target with greater certainty. However، hyperspectral images have the well reaction against concealed targets in forest areas.

Today LIDAR system is the known technology for 3D data collection from earth surface which provides a fast and accurate solution for DSM generation. For LIDAR data correction، the systematic errors should be modeled that is done in system calibration. By studying the effects of different error sources on derived data، optimal flight planning can be done so that the highest accuracy for system calibration is reached. To estimate the calibration parameters، the geometric compatibility between laser footprints in the overlapped or crossed strips should be measured in a coregistration process. After data correction by applying estimated calibration parameters، the geometric compatibility of point clouds gives an estimation of the quality of final data. This paper proposes two methods for coregistration of LiDAR point clouds. In the first method، the point clouds are divided into small planar surfaces and mathematical equation of each surface is derived. Then straight lines are produced based on the intersection of the neighborhood surfaces. Finally، the linear features extracted from two strips are matched. The second method uses the SIFT algorithm to extract and match the point features. At the end، mathematical models are used in both methods to determine the shift and rotation parameters between the corresponding features. Results showed that the accuracy of the second method is about 19% higher than the first one.

In this paper، an automatic close range photogrammetric method for deformation extraction from the object surface has presented. In opposite of the conventional close range photogrammetric approaches، here، utilizing targets is not mandatory. Indeed new feature extraction and matching algorithms can match corresponding image features with high precision in whole object surface. Therefore، the large number of matched points can remove the limitation of accuracy and network reliability in the case of using target for deformation extraction. After feature matching it could be used some linear computer vision and non-linear photogrammetry equations to solve the relative orientation and reach to model coordinate of check points. Then we use an initiative approach to match three-dimensional points of two epochs in the model space to determine the stable and unstable points and analyses the deformation of object. In this paper، after describing the automatic deformation extraction theory، the absolute deflection behavior of a foam beam under a pressure has been measured. To assess the accuracy of the proposed method، a comparison was made between this approach and the Australis software and the accuracy about 1. 5 mm was achieved. According to several tests performed using this technique، the accuracy of a few millimeters in some meters distance from an small size object is reachable.