Showing 9 results for Geographic Information System
S. Z. Mosavi Khatir, A. Kavian, A. K. Soleimani,
Volume 14, Issue 53 (10-2010)
Abstract
In this research, logistic regression analysis was used to create a landslide hazard map for Sajaroud basin. At first, an inventory map of 95 landslides was used to preduce a dependent variable, which takes a value of 0 for absence and 1 for presence of landslides. Ten factors affecting landslide occurence such as elevation , slope gradient, slope aspect, slope curvature, rainfall, distance from fault, distance from drainage, distance from road , land use and geology were taken as independent parameters. The effect of each parameter on landslide occurrence was determined from the corresponding coefficient that appears in the logistic regression function. The interpretation of the coefficients showed that road network plays the most important role in determining landslide occurrence. Elevation, curvature, rainfall and distance from fault were excluded from the final analysis because these variables did not significantly add to the predictive power of the logistic regression. After transferring final probability function into Arc/view 3.2 software, landslide susceptibility map was prepared. The results of accuracy assessment showed that overall accuracy of produced map is 85.3 percent. Therefore, 53% of the area was located in very low hazard, 18.3% in low hazard, 21% in moderate hazard and 7.7 % residual area is located in high hazard regions. Model and then susceptibility map verity was assessed using -2LL, Cox and Snell R2, Nagelkerk R2, and was validated.
M. Arabi, A. Soffianian , M. Tarkesh Esfahani,
Volume 17, Issue 63 (6-2013)
Abstract
Physicochemical characteristics of soil, land cover/use and human activities have effects on heavy metals distribution. In this study, we applied Classification and Regression Tree model (CART) to predict the spatial distribution of zinc in surface soil of Hamadan province under Geographic Information System environment. Two approaches were used to build the model. In the first approach, 10% of total data were randomly selected as test data and residual data were used for building model. In the second approach, all data were used to build and evaluate the CART model. Determination coefficient (R2) and Mean Square Error (MSE) were applied to estimate the accuracy of model. Final model included 51 nodes and 26 terminal nodes (leaf). Calcium carbonate, slope, sand, silt and land use/cover were determined by the CART model to predict spatial distribution of Zn as the most important independent variables. The regions of western Hamadan province had the highest concentration of Zn whereas the lowest concentration of Zn occurred in the regions of northern Hamadan province. The results indicate good accuracy of CART model using R2 and MSE indices.
A. Malekian, H. Alipour, M. Kheirkhah Zarkesh, S. Gharachelo,
Volume 18, Issue 69 (12-2014)
Abstract
Determine appropriate locations with accuracy and speed required is for Floodwater spreading very important. The main objective of this research, preparation, use and evaluation decision support systems is based on GIS and RS techniques to identify and prioritization appropriate areas Floodwater spreading in the study area. In this study area suitable for flood water spreading were selected based on major criteria four, sub criteria eight and index twentyfour. Finally five scenario will be provide and assessment (a scenario based on the relative values for the criteria four, and different scenarios four based on the obvious one of the main criteria). Comparison desirability average among the scenarios five indicate that it is Sub watershed (1) In the scenario third (infilteration preferred, water application preference and equality of all the main criteria) had a higher average desirability therefore between Sub watershed 2 in this scenario is preferred more than the other Sub. Of between the two sub watershed ivar region considering that the desirability average, sub watershed (1) and implemented of between scenarios, scenario (1) (infilteration major criteria preferred) were selected as first priority. Second priority for Floodwater spreading site selection is belong to sub watershed 2, and with scenario (1).
N. Tavanpour, M. Aflatooni, N. Nazari,
Volume 20, Issue 78 (1-2017)
Abstract
This research is aimed to determine the contribution of sub-basins flow to total watershed flood in Khersan river basin located in Kohkilooyeh and Boyer Ahmad province. To do this, the rainfall-runoff model HEC-HMS was used to simulate peak runoff values for 11 sub-basins. HEC-HMS input was constructed using GIS. The results suggest that the change in different return periods is accompanied by small change in prioritization of flood-potential of the sub-basins; so that for return periods of 2, 50 and 100 years, the most contributions came from sub-basins 1 through 11, respectively. With respect to area and flow rate, contribution of sub-basins to watershed total flow was different. The effect of area was between 0.31 to 1.03 percent; namely, sub-basin 6 showed the highest rank and basin 7 showed the lowest one. With respect to peak flow rate, the effect of individual exclusion of sub-basins, resulted in contribution between 51.2 to 1004.2 m3/s, that is, sub-basin 6 showed the lowest effect and the sub basin 11 showed the highest contribution.
F. Amiri, T. Tabatabaie, S. Valipour,
Volume 22, Issue 1 (6-2018)
Abstract
The purpose of this paper was to assess the groundwater quality near Qaemshahr landfill site using the Iran Water Quality Index for Groundwater Resources-Conventional Parameters (IRWQIGC). In this study, samples were taken from 11 wells with three replications in February 2015 and water quality was assessed by evaluating nitrate, fecal coliform, electrical conductivity (EC), pH, total hardness, sodium absorption ratio, biological oxygen demand, phosphate, chemical oxygen demand, and dissolved oxygen parameters with the standard measuring methods; also, the quality of ground water was determined using the IRWQIGC. Statistical description of the parameters was performed using the SPSS software. Spatial extension mapping parameters were drawn using geostatistics extension with the ArcGIS software. The results of water quality assessment revealed that 0.15% of the area was classified as bad, 98.85% as relatively poor, and 1% as middle in terms of quality. The results of spatial dispersion also revealed that water quality from the South to the North and North East was reduced. Evaluating the changes in water quality near landfill sites showed that 2149.56 square meters of total area had a relatively poor potential for the region’s groundwater recharge.
V. Sarvi, H. R. Matinfar,
Volume 23, Issue 1 (6-2019)
Abstract
In the face of rapid growth of the population and the need for food production sectors, one of the ways to achieve this is to increase the production per unit area. In modern agriculture, the preparation of soil fertility map seems to be necessary to plan for appropriate use of fertilizers for crops. This study was conducted to prepare a distinct map for evaluating the soil fertility according to soil chemical properties in 191 soil samples of Ardabil Plain in Ardabil Province. To achieve this goal, the available N and P, K, EC, Fe, Zn, Mn and the organic matter of soil were mapped using geostatistical Kriging estimator into the Geographic Information System (GIS) by the ArcGIS software. The Analytical Hierarchy Process (AHP) was used for weighting the soil fertility factors as the input data. Then, a membership functions was defined for each factor by factorial scoring and the map of soil fertility was prepared and classified by using the AHP technique into the GIS program. The results showed that most of nitrogen and phosphorus with the weight of 0.293, 0.202 had the mostly infraction on the soil fertility and production. Survey map of the distribution showed that most of the factors were studied in the northern region with the low nutrients. The results also showed that 23.7 percent of cultivated land fertility maps had a poor fertility status, 28.3 percent of the land had a moderate fertility status, 25.4 percent of the land was good and the fertile land with 22.6 percent had a very good fertility status.
Sh. Ahmadi-Qolidaraq, A. Abbasi-Kalo, A. Esmali-0uri,
Volume 23, Issue 4 (12-2019)
Abstract
Soil is one of the most important natural resources of countries in which erosion occurs. In this research, the effect of soil characteristics on the amount of erosion at the suborder level was studied. For this purpose, 77 soil samples (0-30 cm) were prepared and the parameters were determined in the laboratory. The semi-variograms of soil parameters and their spatial distribution maps were prepared with GS+ and GIS, respectively. The study area was divided into work units by combining land use and geology maps and water erosion was estimated at each unit by the EPM method. By drilling profiles in different parts of study area, soil suborders were determined by Soil Taxonomy and the average values of parameters in each suborder was estimated. The principle components analysis (PCA) was then used for data analysis. The results showed that three parameters of silt, organic carbon and electrical conductivity could account for 30.384% as the first main component; clay, sand and vegetation could explain 11.189% as the second main component; and slope and height covered 15.330% as the third main component; in total, 63.805% percent of erosion variation could be justified by three main components. The lowest and highest amounts of erosion (69.12 and 343.57 m3/km2, respectively) were estimated in Xeralfs and Fluvents suborders. The erosion class of suborders at the study area was determined to be “few” and “medium”.
Z. Shirkhodaei, F. Aghayari, H. Hasanpour Darvishi,
Volume 23, Issue 4 (2-2020)
Abstract
There are new technologies such as geographic information systems (GIS) that can be effective in the optimization of irrigation water. Therefore, utilizing these resources in a desirable, effective and efficient manner to ensure sustainable development is one of the most important issues in the today's world. The aim of this study was to determine and evaluate the potential water use efficiency (WUEp) index in the plain scale by using net water requirement data, area under cultivation and yields, and to determine the comparative advantage of wheat and barley plants in Tehran, Alborz, Qom, Qazvin and Zanjan provinces by employing the geographic information system (GIS). The yields of wheat and barley products by weighted average in ArcGIS software were converted to yields in the plains scale. To calculate the potential and actual water use efficiency, we used the OPTIWAT software in order to calculate the net irrigation water and the current irrigation efficiency plains; also, the yields of wheat and barley products in the plains scale were used. Zoning water use efficiency indexes was performed by using the ArcGIS software and Kriging method. Mapping results showed a comparative advantage of crops in the west and northwest of Tehran province, south and southwest of Alborz province, southwest, north- west and center of Qazvin province, center Qom province and also, northern and southern regions of the Zanjan province, in comparison to other areas. Average potential and actual water use efficiency in the whole study area of the provinces for wheat were 1.43 and 0.58 kg m-3, respectively, while these were 1.62 and 0.65 kg m-3 for barley, respectively.
A.s. Hosseini Khezrabad, A.a. Vali, A.h. Halabian, M.h. Mokhtari,
Volume 27, Issue 4 (12-2023)
Abstract
Desertification is one of the most serious ecological environmental problems in the arid regions. Quantitative assessment of the desertification process is important for the prevention and control of desertification. In this research, the IMDPA model was used to evaluate the quantitative and qualitative desertification situation in the northwest of Yazd. Three criteria of soil, vegetation, and wind erosion were considered in this model. Several indicators were defined for each criterion with a weight of 0 (low) to 4 (very severe). The geometric mean of all three criteria was used to prepare a map of sensitive areas to desertification in ArcGIS. The results indicated that more than 92% of the research area was in the extreme class of desertification, and only the dunes work unit was in a very intense class. Finally, the whole of the research area with a final score of 3.04 was placed in the extreme class of desertification intensity. Also, the soil criterion with the highest weight score of 3.26 has had the greatest impact on the desertification of the northwest region of Yazd. Therefore, it is necessary to implement remedial and revitalization operations in this region according to the expansion of the phenomenon of desertification and the high influence of the soil criteria. The results of the research showed the intensity of desertification, the potential, and the sensitivity of the region to the phenomenon of desertification can be referred to as a departure from the natural functioning of the system.
