Determining the Optimal Route Using Geographic Information System (Case Study: Sar-Qazvin Route Route)

In the routing, the most basic parameter is to find the shortest path and in the ideal mode of linking the source and destination posts with a straight line. Because by shortening the route, the amount or quantity of equipment needed, such as foundations and foundations on the one hand, and the cost of operational operations such as mapping, geology and soil mechanics, and road asphalt costs, will be significantly reduced. The operation of roads as one of the infrastructural structures in the development of the national economy does not need more emphasis, but nevertheless, the development of inappropriately designed roads will have a significant negative impact on the environment and, in some cases, damage The damaging effects of road development are so great that it undermines the benefits of increased communication and access. The environmental impact of roads on the environment can be attributed to air pollution, noise, surface water and altered patterns, or even the destruction of local communities by displacement. On the other hand, the sensitivity of communication routes in terms of security, economic and social, doubles the importance of this issue, and it is very necessary to pay special attention to the correct and optimal route for the construction of roads. Most routes with conventional methods do not have all the technical and engineering, economic and environmental considerations and standards, and this leads to increased costs of building communication paths and in addition, it can destroy environment by crossing unauthorized areas.

The present research is a descriptive-analytic study which was first studied through library and documentary studies, theoretical frameworks, and literature on route and routing, and then, with field observations and surveys, the required information was completed and by integrating existing maps and collected information is provided in the ArcGIS software environment. In this regard, the use of modern principles based on the GIS can play a significant role in the routing problem solving. In designing the route by GIS, we can model effective factors such as technical, engineering, economic and environmental factors and, by performing the required analyzes, determine the optimal route. In the process of determining the path, the first step in the practical steps of research is the extraction of information layers. Information about the study area, such as roads, faults, health centers, areas of each user's ... file shap format was prepared and collected on a scale of 1/25000 from the municipality. Among the criteria mentioned above, because the desired criterion is the distance from the centers and the zones, the Raster layer must be produced from them and the maps are transformed into a raster format for analysis, using the Analyst extensions commands and functions spatial such as distance and convert raster to features, and ... in ArcGIS10.5 software.

After designing the route by GIS, each route should be evaluated in terms of compliance with the environmental characteristics of the other routes, so that it can select a path that has a lower environmental impact as an optimal route. The choice of the optimal route among the planned routes is in fact a kind of multi-criteria decision making in which the decision goal is the optimal route selection and the criteria for choosing the optimal route including the slope of the route, the land of the road, the type of soil Crossing the route, the intersection of the route with the rivers, the type of land cover, the area of the passageway in the region. Since decision making is about the choice of the optimal route, the issue is very important and the occurrence of the error may cause irreparable losses, it is necessary to adopt reasonable and appropriate methods for choosing the optimal choice and the correct decision. In this research, the Analytical Hierarchy Process (AHP) process, introduced by Professor Sahyati in 1980, has been used.

Suitable road design and road planning are among the factors influencing the sustainable development of cities, which increase the efficiency of the road network, reduce costs and shorten paths. Establishing an offshore road network with a variety of goals from the executive branch of scientific management and optimization in the field of road safety and the road to sustainable development. Urban roads, in addition to being costly in designing, constructing and maintaining, as well as negative environmental impacts, have a special economic, environmental and public opinion sensitivity. Therefore, proper design and compliance with the necessary standards in this regard will be necessary. In order to build any new way, the first step is to select an optimal route. It's wise to always choose the best route with minimal cost. In order to determine a path, it is often necessary to evaluate several criteria and since, in the routing process, there are several quantitative and qualitative parameters that are practically independent and mutually interacting, it is necessary to use the multi-criteria evaluation method as One of the decision support methods used in this research is the use of GIS capabilities in building a database and performing various analyzes on it, the possibility of interfering with all the effective parameters in determining the optimal route was provided. In order to determine the optimal route, 12 criteria including geology, police stations, power lines, landslide, residential areas, distance from the road, distance from faults, erosion, elevation, slope, flood, land use were used. Based on the research, it was found that the designed road passes through less relative obstacles such as rivers, urban and rural areas and avoids all sensitive areas of the environment. As a result, the total cost of collecting the cost of different information layers is less due to the observance of privacy and the reduction of adverse environmental effects. Also, with regard to all the tracks, it can be said that the restrictions, especially their distribution, play an important role in determining the route, in other words, the main role, and the range of the route is limited by these factors and taking into account the shortest distance of determination gets.