نشریه اطلاعات جغرافیایی (سپهر)
پیاپی 76 (زمستان 1389)

Digital orthophoto contains maps and geometric features of the map, and is accordingly able to:1) As a source of spatial geography, be complemented by descriptive information.
2) Provide a base on which other data are recorded and adjusted.
3) The results of using it will be available to match landscapes.
In many countries, digital orthophoto is an important part of the graphic documentation, and is used at strategic levels, which provides appropriate cartographic features on a national scale.
Digital orthophoto has a strong potential for analyzing the geographic information system (GIS) data. Not only is orthophoto a layer of information, but the connection of orthophoto digital data presents a new perspective to automatic extraction of positional data (point, line, and surface) and altitude information.
A large-scale orthophoto is prepared with a great deal of details, and makes the revision of many of information layers possible, and in some cases, plays a background role and is used to represent the position of elevation features. Therefore, large-scale satellite orthophoto has, in many cases, overcome the defects of orthophoto and, in accordance with the scale of study and urban planning, presents a valuable efficiency in detecting buildings hidden among complexes and high-rise buildings.

Urban planning research, like most behavioral sciences and human research, should be supported by a proper theoretical framework or conceptual model. In this theoretical framework and conceptual model, the variables and factors affecting the subject matter are identified and their relationships are determined. To assess the validity and correctness of these models, there are different qualitative and quantitative techniques and tools. Structural equation modeling is one of these quantitative and multivariate tools that examines and evaluates the fitting of the model and allows for some modifications in the model. In this paper, along with introducing the technique of modeling structural equations and Lisrel software, its application in urban planning research is described

Nowadays, the complications of fast, unrestricted and unplanned urbanization and lack of proper management in some cities have reached a level that it has basically made urbanization an undesirable phenomenon with a negative value.
The tendency towards more concentration and polarization in the upper levels of the urban community and the distance between the high levels and the low, the tendency towards thoughtless growth in terms of disparity between the scale and performance of cities and ... are among the factors that cause the increasing decline in the efficiency of urban per capita income , speculative activity, dominance of unofficial sector on the official, and the growth of social-cultural crises, and as a result, the sources and factors of production have swallowed their own region and create their own further growth.
In this regard, the old texture of the city of Khorramabad, despite its potential historical, economic, social and cultural capabilities, suffers from these problems. The composition of the population, the cultural differences of the inhabitants, and legal problems that are the outcome of the lack of proper and principled policy-making are among the characteristics of this texture. The low value of land and buildings, the lack of social and psychological security, the dominance of low income jobs and the presence of significant poverty in the old texture of the city compared to the new are also among the characteristics of these types of textures.
The main objective of this study is to identify the physical-functional structure and the issues and problems of the old texture of Khorramabad city. The results of the research show that the absence of suitable executive plans, lack of urban unit management, issues and legal problems related to property ownership, economic and cultural poverty, old and weary buildings and their lack of renovation, and ... are among the main problems of this texture. In this paper, we have studied physical-spatial and functional problems of the central part of Khorramabad using secondary, descriptive and analytical research methods along with field study.

The limitations of the sources and documents related to the field of space in the country necessitates the clarification of the status of space in the development of the country and sustainable security, which, while expressing the fundamental issues concerning space technology and space activities of the country, examine specialized fields in remote sensing and space imaging. Space structure, space legal regime, space functions and space technology are the major topics discussed in this paper.

Cities are open systems that have always been the origin of change and are themselves changing and evolving, and given the growing population of cities in today's world, the physical space of the city has also expanded and occupied the surrounding land. The physical growth of cities has absorbed and destroyed high-quality land.
Human societies have been established in the early stages of formation with the aim of using high quality soils for agriculture, alongside or among high quality agricultural land. Over time, along with the expansion of the villages and their conversion into cities, and then the development of cities, high-quality agricultural lands have been added to the urban area and agricultural activities are retreating to poor lands.
This article tries to understand the environmental impacts of urban development using a method based on secondary sources, and the results show that this issue is taking place continuously in parts of the suburbs of any city with potential of development and expansion. This physical growth of cities causes the destruction of the environmental balance between the city and its surroundings, which not only reduces the quantity and quality of resources and living conditions, but also causes major complications such as air and water pollution, noise pollution, and In general, the destruction of the environment.

Investigating factors effective in occurrence of landslides in a region and the zoning of the resulting risks can effectively help reduce the damage caused by this phenomenon. The present research is an attempt in this field, and by analyzing the effective factors of landslide formation, attempts to carry out the zoning of the risk of mass movements of Gharah Chay watershed using analytic hierarchy process (AHP). Gharah Chai Basin is one of the sub-basins of the Atrak River. In this study, first the factors affecting the occurrence of landslides in the area were investigated, and the most important factors were identified to be lithology, slope alignment (structure, topography), slope, slope direction, land use, distance from village, the drainage network density, distance from river, distance from fault, and elevation classes in order, and then the landslide distribution map was prepared. In the hierarchical analysis method, the ten above factors were used. In this method, the factors considered are compared in pairs and the weight of the factors is calculated. For classifying the factors, they were scored with taking the percentage of slip level into account.
At the end, the zoning model was obtained by considering the weights obtained for each factor and the scores obtained. Accordingly, the range was divided into five level of risks. The map was divided into five classes with very high (2.6 km2), high (14.4 km2), medium (14.5 km2), low (4.6 km2) and very low risk (1.8 km2).

Today, airports are not complexes like passenger terminals and large railroad stations, with cars and passengers on the one side, and on the other side the planes, but airports have gained a multi-purpose existence.
Nowadays, by increasing the capacity and efficiency of the airports on the one hand, and paying attention to issues such as sustainable development and environmental protection on the other, consideration of geographical factors in the location of airports is deemed very important, as in developed countries It receives a great deal of attention. Among the geographic factors affecting the location of the airport, the climatic and topographic components play a greater role, as they have a great influence on the efficiency and activity of the airport. The main objective of this paper is to assess the strengths and weaknesses of the locating process of the country’s airports based on climatic and topographic factors.
To achieve this goal, secondary and field methods have been used. Based on the findings of this research, insufficient attention to climate and topographic factors in the location of airports in the country has led to a decrease in the safety and health of the flights and, in some cases, severe and fatal accidents. This Situation can be improved by correction of existing deficiencies and the application of geographic factors in future plans.

One of the important issues in the field of surveying or military affairs is to determine the coordinates of the points on the earth, from which the distances, angles and other parameters of a point compared with the target or any other point can be measured, for which there are many methods including photogrammetry and land surveying, especially effective for short distances. But, due to lack of direct vision, these methods are not efficient enough for very long distances, such as thousands of kilometers between the continents. In this case, space and astronomical objects should be used because of the insignificance of the intercontinental distance compared to it, as well as the simultaneous view of the two stations and the space mass in a constant time. The present study describes the method of determining the location using the received waves from anonymous space objects.

Today, airports are not complexes like passenger terminals and large railroad stations, with cars and passengers on the one side, and on the other side the planes, but airports have gained a multi-purpose existence.
Nowadays, by increasing the capacity and efficiency of the airports on the one hand, and paying attention to issues such as sustainable development and environmental protection on the other, consideration of geographical factors in the location of airports is deemed very important, as in developed countries It receives a great deal of attention. Among the geographic factors affecting the location of the airport, the climatic and topographic components play a greater role, as they have a great influence on the efficiency and activity of the airport. The main objective of this paper is to assess the strengths and weaknesses of the locating process of the country’s airports based on climatic and topographic factors.
To achieve this goal, secondary and field methods have been used. Based on the findings of this research, insufficient attention to climate and topographic factors in the location of airports in the country has led to a decrease in the safety and health of the flights and, in some cases, severe and fatal accidents. This Situation can be improved by correction of existing deficiencies and the application of geographic factors in future plans.

Aggregates are part of building materials including hard materials such as sand, gravel and rubble, which, after being combined with other adhesive materials, can be used in the production of concrete, mortar and plaster, and in the construction of roads and railways, Bridges, tunnels, dams, airports, and other construction purposes. The present study investigates the formation, dispersion and distribution of aggregates in relation to landforms and geomorphologic processes. The result of this study is that a large part of aggregate resources are formed in river landforms or alluvial environments such as the current and old river basins, the intersection of the rivers, the new alluvial terraces, and parts of the alluvial fans.
In glacial environments, forms such as alluvial ice plains, kames and eskers are considered as among prone areas for the formation and exploration of aggregates. In coastal areas, continental shelf sediments and littoral drift and some ancient geomorphological forms, and dunes in the desert areas are capable of exploring aggregate resources.
In erosional anticlines or anticline ridges that are hard at the top and loose at the bottom, there are large zones of debris that, if fresh or poorly weathered, can be a very good source for extraction of aggregates.
Also, geomorphologic processes such as weathering, erosion and transportation of materials, physical and chemical degradation, as well as tectonic factors and geomorphologic changes play very important role in the formation, dispersion and quality of aggregates and building materials

Postmodernism is considered to be the most prevalent feature of modernism, which is characterized by a combined imitation (Pastiche). The postmodern moment comes when the avant-garde (modern) is no longer able to continue and advance, and can not go a step further. The postmodern response to modernity implies acknowledgment of the fact that the past must be reconsidered or revised, because the past can not really be destroyed, because the destruction of the past leads to silence. Postmodernism indicates a new kind of crisis in the modernist culture itself. This crisis emphasizes that scattered, decomposing, passing, turbulent and disordered aspect in Baudelaire’s formulation. Post-modern state of affairs has been closely associated with the growth of cities, particularly with the dramatic trend of urbanization and migration to major cities in recent decades. But this growth of cities was beyond what Le Corbusier and Max Weber considered to be for civilized and rational groups. In general, modernism and postmodernism have influenced various fields of literature, art, architecture, urban sociology, social theory, and urbanization, and their influence is still evident in these areas. In this article, written by descriptive-analytical method, we try to consider the concepts and characteristics of modernism and postmodernism in the field of urbanization, their differences and effects, especially of postmodernism, in different urban areas including physical and non-physical.

Natural lakes and artificial reservoirs (dams) are considered as reservoirs for storing water in the watershed area, as well as for the accumulation of fine sediments derived from the atmosphere, and thus containing valuable information on the time variations in these entrances. While the use of sediments of natural lakes as environmental documentation has been validated, the use of dam deposits (artificial lakes) as time records has been less frequent. But, apparently, for the purpose of examining the past pollution, artificial water resources are more attractive: these reserves are mostly located in proximity to cities and industrial pollutants, and sediments accumulate rapidly and simultaneously with the spread of contamination. The lack of interest in artificial reservoir sediments has been due to this view that the change in the level of water resources of these reservoirs is likely to cause considerable disturbance in reservoir sediments. This perception may be reinforced by the absence of research into sedimentary systems of artificial reservoirs. Therefore, there is a need for a revision of published research (relatively few studies that use sediments of artificial water reservoirs and studies on the literature of sediments of natural lakes) about the patterns and processes of artificial reservoirs, and thus, vitally assesses the potential and problems associated with the use of water deposits as time records of contamination. The current understanding of sedimentation processes and distribution of sediment resulting from those processes is revised. Some important differences between artificial and natural lakes are emphasized and the requirements for sampling and interpretation of sedimentary data are discussed. It is suggested that a valuable source is currently in use, and it is also shown that artificial reservoir sediment data can provide important data for understanding and reconstruction of atmospheric pollution and watershed of these resources.

In the present era, the importance of productivity and the promotion of the performance of companies and organizations in a competitive environment has encouraged them to make more efficient use of computer networks. This is not only possible without the provision of fast, inexpensive, full time, easily available, secure and sustainable services. Therefore, organizations and companies, in the competitive world, must purchase, install and maintain a variety of equipment and hardware, and pay their capital and communicative costs. High costs, lack of skilled human resources, and failure to meet the standards are among the problems of these organizations. To solve these problems, data centers have been developed. These centers, with extraordinary security, strong support, and specific conditions, provide a platform for organizations and companies to leave their data, programs and services to these centers to be used by themselves and their customers remotely. Sooner or later, most Government agencies will have to move towards data centers as a result of high data volumes, the lack of a centralized storage system, availability issues, and security problems. In this paper, using a federal organizational architecture framework, a methodology for architectural design of a data center is presented.

Precipitation as one of the climatic elements is an appropriate index for climate change. Precipitation in the studied years and the years before and after it shows the instability and the many fluctuations whose prediction, based on the probable precipitation formulas in hydrology, is very simple, important and practical, and can help prevent financial and life losses in the future. In this research, using the 21-year precipitation data in 12 stations of Golestan plain, the characteristics and the quality of precipitation, the monthly-seasonal and spatial precipitation regime, have been analyzed and presented through columnar and circular diagrams and tables, and since precipitation is an unstable climatic element, which changes from year to year in terms of time intervals, and it can not be expected that the behavior of the climate be the same and homogeneous everywhere, therefore, in calculating the empirical probabilities of occurrence of precipitation and probable precipitation, their monthly and yearly variation coefficients have been analyzed.

Today, we are facing with the ever-increasing advances in remote sensing and aerial photography and satellite imagery, with the increasing use of remote sensing and GIS in environmental planning, especially in various branches of natural sciences and earth sciences. In this paper, we have tried to examine the role and application of satellite imagery in environmental studies. GIS can be considered a high-level mapping product. The term "GIS" has been used in recent years as synonymous with the rapidly emerging technology for the processing of spatial data. GIS can be defined as a powerful set of computer tools for collecting, storing, restoring, transmitting and displaying spatial data from the real world for specific purposes.