جستجوی مقالات مرتبط با کلیدواژه « داده های رقومی » در نشریات گروه « جغرافیا »

Availability of spatial information and decision making based on the analyses performed by geographic information system are among the fundamental components of sustainable development. For this purpose, an organization or more is responsible for the production of spatial information in different countries. In recent years and in the era of information technology and public access to internet, creating a platform for providing spatial information in cyberspace is considered to be much more important. As a result, the new generation of spatial information products have the capability of being presented and disseminated in the cyberspace. Some organization have proceeded and not only pioneered for dissemination of spatial information in the Internet, but also have provided users with the possibility of performing some basic spatial analyses. In developed countries, these possibilities are available and spatial information is being provided in cyberspace. In order to take advantage of developed countries knowledge and experience in producing and disseminating spatial information, it is necessary to evaluate the procedure of producing spatial data in these countries. USGS in United States of America and Survey Ordnance in UK are responsible for producing spatial data. Therefore, the present article investigates the procedure of producing spatial information.

Intro duction Water resources are studied and exploited in two divisions: surface and ground waters. Ground water recourses, due to certain characteristics such as freshness (in terms of contrast with seawater), constant chemical makeup, Constant temperature, lower pollution index and higher dependability as a water supply, are considered a reliable resource especially in arid and semi – arid areas. Ground water recourses are, excepting ice – mounds and vast ice – covered areas, the most significant freshwater resource (Sedaqat1994: p.7). 97% of the global use of fresh water is obtained from ground water resources whereas these resources with an overall volume of 37 billion cubic kilometers constitute only 22% of the world's fresh water resources (Foster 1998). Madman et al (2008), studying the role of ground water resources in the ecological potential of land, attributed a significant role to these recourses in terms of economic development, ecological variety and social well being The exploitation of ground water resources at a rate faster than their replacement and the fall of ground water level considered one of the most important enduring challenges of development worldwide.El–Naka et al(2008) studying the role of water resource and its significance in the development of Jordan, showed that over – use, the fall in ground water quality and a lack of yearly precipitation resulted in a steep decline in water level in most water – beds and subsequently a lapse in the country's development programs. Shahid and Hazarika(2009) studying ground water drought in the Northwestern Districts of Bangladesh. In this paper, groundwater scarcity and drought in three northwestern districts of Bangladesh have been investigated. The Cumulative Deficit approach from a threshold groundwater level has been used for the computation of severity of groundwater droughts. Iran, after the highly populated countries, china and India, is the third unrestricted exploiter of groundwater recourses and with a 75% usage of restorable resource as against the 40% UN standard, is in an unsuitable situation (The National Society of ground water Resources.2006). In light of the given statistics, a review of management strategies for water resources and a reconsideration of economic and social planning deem a serious necessity. The ChaharMahal&Bakhtiari province covering an approximate one percent of the country's surface and as the supplier of 10% (10. 5 billion cubic meters) of the domestic fresh water supply (M.P.O, 2005) has a significant place in relation to the enhancement of the country's water resource status. In this province due to certain factors including severe shifts in altitude, economic underdevelopment the high cost of pumping water, the role of surface waters in water supply is approximately 15% (equivalent to 225 million cubic meters).The remaining demand for water which is approximately 85% (10275 billion cubic meters) is supplied by the ground water recourses of the province. Over – exploitation of ground water resources in conjunction with the effect of recently occurring droughts has not only lowered the water level of the provincial water – beds with a rate of 2- 12 meters annually, but has also lowered the quality such that the electric conduction amount of some water – beds has Changed from a 300mm level to 900mm (Management and planning organization2001). 2- Methodology In this article, Shahrekord plain is choose for reserch,that has decrease water level, the mountain–bordered Shahrekord plain in the province of ChaharMahal&Bakhtiari was chosen. This plain (water – bed) with an altitude of 2000 meters from sea level and a surface area of 125000 hectares, 21 rural settlements and one urban settlement are situated in the Shahrekord plain (Iran data center –2006). From a hydrological perspective the plain is a part of the Karoon basin (north Karoon basin) in which the Jahanbin river flows (provincial basin registration, 1998). The shahrekord plain is, geologically speaking a descended plain constituted by quarts sediments with an alluvial depth of 60 – 110 meters (M.P.O 1986).Map (1) shows the geographical standing of the Shahrekord plain.