نشریه اطلاعات جغرافیایی (سپهر)
پیاپی 48 (زمستان 1382)

Satellite sensors provide the opportunity for continuous multi-time measurements of a vast area over a period of several days to several decades. Sensor coverage and distance repetition are determined by the height of the shooting platform (satellite), angular acceleration, orbital inclination in proper relation to the equator, and determining the position in proper relation to spring equinox (Elachi, 1987). Many optic sensors have been deployed in near-polar solar synchronous orbits so that global coverage and geometry of continuous light can be achieved. The distance repetition between sensors is different because it depends on the elevation and acceleration of sensors. Other sensors have been placed in the Earth's synchronous orbit so that a high coverage frequency can be obtained from that area. (For example, GEOS meteorological satellites) The ability to detect changes in the surface area photographed over time depends on the recording of spatial geometry and spatial resolution, spectral width and spectral band location, and the radiometric and temporal properties of the sensor imagery frequency. Comparison of received images by a sensor in different dates with any variations in deviation of measuring device and the difference in atmospheric characteristics, is particularly complicated in the secondary pixel cloud coverage. Detection change is considerably more complicated when more than a sensor system is used due to differences between IFOV and PSF sensors, and in bandwidth and spectral response properties.

This paper has two basic objectives 1- Reviewing and evaluating major rural development strategies that have been used in the developing world. 2- Providing a successful rural development model in China (studied in this paper). Major types of rural development and rural development courses of action are presented in Figures 1 and 5, respectively. The significance of the increase of efficiency in rise in agricultural productivity of the Third World is shown in Fig. 2. The increase in fertility in Asian agriculture is often referred to as the "Green Revolution". The meanings associated with the phrase Green Revolution, the strategy of this revolution and its positive and negative aspects have been discussed and, in necessary cases, the relevant developments have been traced until the 1950s-60s. China has been especially at the center of attention, where many different methods have been tested for rural development (Fig. 5). This country has undergone various stages of rural development that can be summarized as follows: 1. Land reform 2. Collective agricultural system 3. The dissolution of the collective agricultural system 4. A New Peasant Economy

The bombing experts who have a very different view of urban warfare than conventional street warfare experts and experts of special force operations, support two major options or a combination of them. Option (B) is a precise bombardment of selective targets that will degrade enemy’s capabilities and military potentials through destruction. Option (A) emphasizes the conventional regional bombardment designed to undermine the enemy's will deliberately.

No region is independent from the point of view of climate, and the dominant climatic pattern in one region affects other regions, because there is a systematic atmospheric relationship between them in spite of climatic disparities between different regions; for instance changes occurring in tropical regions cause atmospheric differences between the areas of mid-latitude and other areas. In general, there is always a completely distinct relationship between dominant weather conditions in high latitudes and those of low latitudes. Therefore, the earth's atmosphere works as a single system, in such a way that the change of air circulation from an area of the northern hemisphere to other parts affects the upstream or downstream of that region (Busher, translated by Qaemi, 1994). The purpose of this paper is to present the variable state of air circulation, help provide a relative knowledge of climate change and unusual situations of pressure and air flow in the North Atlantic. The behavior of pressure systems in the Atlantic Ocean affect each other, and on the other hand they can also affect the climate of Iran directly or indirectly (Alijani, 1987). Hence, the knowledge of the status of these systems will be a basis for understanding the origin of some climatic behaviors in Iran. In order to understand the synoptic patterns generated from different phases of the North Atlantic oscillation, pressure distribution and abnormalities on the surface of the earth and in the Atlantic Ocean have been considered.

The tide is a completely complex phenomenon that was fully described in the middle of the nineteenth century. The majority of confirmed popular opinions concern this issue. For example, we often assume that the Earth's rotation around itself displaces a great deal of water and creates a tidal wave, or a decrease in the distance between the Sun and the Earth produces moderate tides. In fact, tide is the result of a system of waves that rapidly spread in the oceans, and produce regular fluctuations of water levels. The order and magnitude of the fluctuation of this phenomenon depend on both astronomical (relative position of the Moon and the Sun) and geographic (coordinates of the studied area) factors.

Earth: The Planet of Water. More than three quarters of the earth's surface is covered by water. Here is a view of the Indian Ocean. The white frozen surface strikes the eyes in the lower part of the globe. The earth, the planet of water, is covered with a thin shell of air that we breathe and protects us. Chemical factors are responsible for destruction of the thin layer of ozone, which is responsible for protecting humans from ultraviolet rays emitted from the sun. The energy from fossil fuels and destruction of tropical rainforest has caused changes in greenhouse effect of atmosphere, and it can be thought of as the reason the earth is moving toward becoming warmer. All planets are regularly bombed by deadly winds caused by solar energy particles. The dawn is the result of a spectacular light that is created by the sun and a radiance like a cosmic light. Old magnetic rocks indicate that magnetic poles of the earth have the task of protecting the parts containing electric current, and it is likely that the magnetic field of the earth is already at the peak of a sudden blow. Boston and Italy have been part of the continent of Africa, and a natural glacier covered the Desert. The Pacific eroded the Colorado coastline. These continents were welded together and brought about a row of mountains, thus forming part of the existing oceans.

Golestan province has a favorable climate due to its geographical location, weather conditions, land lay, relatively vast vegetation and quantities of available water. The average precipitation of the province is approximately 3 times the average precipitation of the country. The total volume of surface and groundwater in the province is 2.4 billion cubic meters, of which 52% is surface water and 48% is groundwater. Currently, half of the total water resources of the province are exploited, and most of it is out of access. Water resources of the province can be divided into two main types of surface and underground.

Military and civilian flight simulators have progressed vastly over the past ten years. Computer, electronic and robotic advances have made the simulators improve day by day and become more efficient in piloting training, and, given the growing need for them, this industry has become one of the most important industries in the air transport sector, and today we can see that flight simulators are one of the key factors in flight programs. The first simulator was used in the 1920s under the name Link Trainer, nicknamed the Blue Box in the United States. Subsequently, simulators and flight training systems on the ground developed and advanced dramatically, so that the business of the industry was $ 1 billion in 2000, and it is estimated that in 2007 this figure will reach 1.6 billion dollars. In recent years, only 30% of this amount has been allocated to the private sector in civilian aircraft, but due to the declining investment of countries in military sections and the increased use of air lines following economic prosperity, it is anticipated that private sector will overtake military section and attract more investment. Simulators include three types of systems: full simulators, medium-range flight training tools, and new software applications that work with home computers.

Wind deposits are caused by erosion, displacement and discharge of non-solid materials by wind. Sedimentary deposits are caused by major wind, sandy hills and clay deposits. Sandstones include hills or sandy ridges that are caused by wind blowing. They are usually found where a sand source is available and the wind is strong enough to erode and carry sand particles of the same size, and where sand deposits on the surface of the earth. These conditions are usually found on inlands, through sandy beaches with coastal winds, close to creeks with exposed sandy floors during dry seasons, and in desert areas where sandstone and rocks’ breakdown create sand. In addition, the moraine-like washed sediments and areas of moraine sandy lake beds often provide a sandy source. Since wind speeds are rarely strong enough to lift sand grains more than 1 to 2 m above ground level, sand grains are displaced by the "gradual advance" process (3), so that the grains move in approximate range of 0.5 to 1 meter above the ground through collisions and jumps. Sandy hills are slowly formed with an asymmetric cross-section with a slope of 5 to 10 degrees in the direction of wind and 30 to 40 degrees in the opposite direction of the wind. As long as sand hills are not stabilized by growth of plants, sand hills move along the wind direction because the sand grains of the hills fall from the direction that the wind blows towards the opposite direction (the side on which the sandy hill can not be threatened). The movement of sandy hills is usually less than 30 meters per year.

One of the problems encountered by researchers in natural science and related sciences is lack of homogeneity in precipitation statistics of pluviometry stations in a region or a basin. Thus, the precipitation statistics of one or more stations do not match those of other stations, and this implies that a favorable relationship between precipitation and elevation cannot be created and the level of correlation among relations is very low. The reasons for this issue can be varied. In this paper, first it was attempted to specify the stations with conflicting statistics and then it was tried to justify the reasons causing these disagreements. The SPSS Software, a statistical software package, can assist surveyors in this task because using this software and the T test it is possible to compare the statistics of precipitation of a station with the average precipitation of the region, and to determine the agreement or disagreement of precipitation data in this station with the whole of region. In addition, it is possible to compare statistical data of two stations and to examine their agreement.

Although the history of construction of new cities with previous plan dates back to the time B.C., the New City movement is related to the beginning of the twentieth century, at the suggestion of Ebenezer Howard (1850-1928). In Iran modern urbanization has begun since about 1921 and construction of Noshahrs (new cities) in recent decades has been considered in order to settle the overflows of population of large cities and inhabitants of industrial centers and for military, political and economic purposes. The urbanization of Isfahan province has increased dramatically in the last decades in terms of developing economic activities in the agricultural, services and especially industrial sectors, and, in addition to creating inconsistencies in geographical distribution of urban population of the region and the province, it has caused many social and environmental problems and difficulties. Therefore, urban planners have chosen the policy of creating new cities in Isfahan region and constructed new cities in line with the policy of urban centers development, settlement of surplus of population of Isfahan city and reduction of its problems as well as settling industrial section employees. It is worth noting that some of these Noshahrs, while accepting part of the population surplus in Isfahan, face particular problems. In this paper, using scientific, descriptive and documentary methods, the situation of the Noshahrs of ​​Isfahan region has been analyzed and finally some strategies have been proposed for the planners of new cities

Rainfall is a climatic element that changes year by year, and in fact rainfall is a random variable over time. If the long-term rainfall data are available, the probability of occurrence of precipitation can be determined by statistical methods. In this study, the city of Semnan has been selected in order to determine the probability of annual, seasonal and monthly precipitation. Precipitation data in this city have been analyzed using computer software and statistical methods. Wet and dry periods, seasonal and monthly variations in precipitation and the probability of occurrence of seasonal and monthly precipitation have been determined.

The system in discussion is a new tool and capability on the SPOTS satellite sensor, which we were eagerly waiting for. SPOT IMAGE and its partners have gained very good results out of this key innovation for customers of Digital Elevation Models (DEM) and geometrically corrected images with appropriate precision. On the SPOTS satellite a system called High Resolution Stereoscopic (HRS) was designed over a period of five years for creation of a Digital Elevation Model (DEM) for a coverage of 30 to 50 million square meters (one-third of the earth’s drylands). HRS is able to provide almost simultaneous topographic (stereo) images from very large areas. Its coverage is 120x600 km at every passage of satellite. This sensor will provide 126,000 square kilometers of coverage stereo images in just one day. This remarkable ability to provide stereo images at the same time is a step forward, not only for production of a digital elevation model (DEM) in vast areas and topographic maps, but also for automatic production of vertical images with very high geometric precision.