نشریه مهندسی نقشه برداری و اطلاعات مکانی
سال چهارم شماره 2 (پیاپی 14، خرداد1392)

From past two decades, Mobile phones as simple devices have mainly been responsible for our daily communications. Despite the dramatic improvements in their performance,combination of mobile phone technologies with Geographic Information System (GIS), underlie the emergence of another technology also known as Mobile Geographic Information System (MGIS). In the older GIS technologies in which they were incapable of employing portable devices, the possibility of making correlations in between the physical and virtual worlds seemed very unattainable. However, nowadays, due to increase in computational processing power of mobile devices and improvements incommunication infrastructure, the spatial analysis can be attained in another form byMGIS. Today, employing a wide range of different sensors in electronic devices suchas mobile phones, tablets, clothes, etc has attracted the attention of many manufacturers. On the other hand, by using the sensor's facilities, high efficientcontext aware services can be developed in mobile environments. Hence, in this studyposition and orientation sensors in mobile devices with Android Operation Systemwill be explained.

The study has investigated the perturbed earth orbits and changing of orbital elements due to the Earth oblateness considering the zonal harmonics, up to 10 times. At the firstreview, after analyzing the Earth potential pattern, the next purpose was the analysisof this effect on polar coordinate system inorder to generate Gauss perturbeddifferential equations. The Legendre polynomial extended up to order 10 and required simulations were performed for a typical satellite. Analysis of each of coefficient effects, j2 to j10, has been done, and produced the net effect of each Jn and combined effect of J2 to J10. These results led to the production process and the behavior of the elements changes with increasing Jn and provided the evaluation of the contribution of eachfactor on each of six orbital elements.

The main problem in the star trackers is when it is in the lost-in-space mode that no attitude information is known a priori. In this mode, using algorithms should be robust against false stars in acquired images and be able to estimate the accurate attitude of theplatform in proper time. Processing algorithms consist of three main parts: star centroid estimation, pattern recognition and star identification, and attitude determination. In this study, the different stellar patterns are described that are used in matching and star identification process. For this, the position of stars within sensor’s field of view is calculated in the image coordinate system and the stellar patterns are generated using these positions. Then, the guide stars are selected from the well-known astronomical catalogue which are used to facilitate pattern generation and recognition based on using algorithms. If the image stellar pattern matches a unique one built up by guide stars, theidentification is accomplished. In this study, three common pattern recognition methods such as the triangle, planar triangle and spherical triangle methods were reviewed and were compared based on the required time, efficiency, the success rate, etc. As a result, the performance and the success rate of the planar triangle method is higher than twoother methods without a high computational burden and complexity.

As the pattern of urban development, especially in the developing countries, shows that the density of activities and volume of settlement in the cities are increasing. These increases reflect the growing requirements and demands of citizens for public services.The absences of such facilities result in dissatisfaction of citizens. According to Muslims belief, cemeteries are one of the important places. Replete capacity of cemeteries and lack of studies for finding suitable new cemetery location in big cities in the next decade cause a serious crisis. Thus, the problem of finding a suitable location for a cemetery in city of Isfahan, one of the big cities in Iran, is addressed in this paper. In the first phaseof this study, the effective criteria are identified, and required spatial data are collected. Then, the fuzzy factor map of each layer is generated and multiplied to the weight of corresponding criterion. Afterwards, the maps are overplayed using fuzzy operators. According to evaluation of results, the selected potential locations for cemetery satisfy all economic, social, and environmental requirements.

G-NAF is a process to create and maintain a live database of the most recent authoritative addresses provided to PSMA Australia by the state and territory addresscustodians. In this paper custodians and executive body as well as specification and applications of G-NAF are described. Content, structure and hierarchical data model, data exchange standard, classification and data processing based on Febrl is other parts of this paper.

Location-based Services become part of our everyday life, ranging from traffic prediction systems to services over mobile phones. Services, users and the concepts of time, space and movement are fundamental sub domains of LBS applications and have commoncharacteristics. As these sub domains are complicated and heterogeneous, theontology is used as the core of fundamental structure in these services. In this paper after defining the existing methods of ontology in Location-based Services, in order to share and clarify the common concepts of space, time and movement that are basics of Domain Ontology and all the LBS applications, a systematic research about meaning ofthese concepts has been done. Finally, in order to help understanding of Domain Ontology, its implementation in an open source ontology editor, Protégé, is analyzed.

Due to high earthquake potential of Iran, the problem of Land Slide has been increasingly investigated in the recent year. This investigations can be performed in absolute and relative measurement of displacements. In the absolute measurement problem, GCPs are always needed while there are no needs to any ground coordinates in relative measurement of Land Slide displacements. One of the methods that can be used tosolve relative problem, is to use RPCs. In this method, pixel coordinates will be observed in both forward and backward stereo images in corresponding epochs, then 3D ground coordinates of observed points will be computed by using RPC coefficients. The next step is compute the displacement by differentiation of 3D ground coordinates in two epochs. The goal of this paper is to investigate the effect of relative RPC shift and drift errors on 3D ground coordinates. In order to reach this goal, two datasets, Roudehenand Damdol with 400 and 43 points respectively, have been used and their relative RPC shift and drift errors are computed. As a result of this research, the effect of this error in x and y directions was measured 1.8 and 9.5 meters respectively. Also the vertical error caused by RPC shift and drift was measured about 0.48 meters in the Roudehen area. The same error in x, y and z directions in Damdol area was measured 1.37, 7.15 and0.4 meters. This results led the conclusion of this research to this issue that RPC shiftand drift error should be necessarily eliminated in 3D reconstruction problem due to its high effect but it will not cause any accuracy issues in Land Slide problem and because of its relative nature it will be eliminated in displacement equations.