Roozbeh Shad; Mohammad Sa'di Mesgari
Abstract
Nowadays, geospatial information systems (GIS) are widely used to solve different spatial problems based on various types of fundamental data: spatial, temporal, attribute and topological relations. Topological relations are the most important part of GIS which distinguish it from the other kinds of ...
Read More
Nowadays, geospatial information systems (GIS) are widely used to solve different spatial problems based on various types of fundamental data: spatial, temporal, attribute and topological relations. Topological relations are the most important part of GIS which distinguish it from the other kinds of information technologies. One of the important mechanisms for representing topological relations between spatial objects is spatial topology. These mechanisms help users to model spatial analysis on the objects simply and efficiently. Topological relations which used for the analysis are influenced by uncertain resources such as: inaccuracy and error of measurements, vagueness to describe information, incompleteness, inconsistency and impreciseness. Then, the fuzzy set theory as an ideal tool can help to handle these uncertain resources in the topological relations. Our methodology relies on the 3D fuzzy 9-intersection, which is a generalization of the crisp 9-intersection of Egenhofer and co-workers. The similarity between the 3D fuzzy and the crisp 9-intersection enables the decision variables, to be derived. The decision variable includes a semantic part and a quantifier. Since determination of the decision variable depends on the definition of the boundary of the fuzzy regions, we try to present a useful method for computing fuzzy boundaries. For this purpose each point of a Fuzzy region has partial membership degree to Interior, Boundary and Exterior set of a region. In order to derive the topological relations between fuzzy spatial objects, the 9-intersection approach is updated into the 3*3-intersection approach in the crisp fuzzy topological space. The topological relations between simple fuzzy regions can be identified based on the topological invariants in the intersections of the matrices. With respect to this, we try to check and complete our information about how we can define 3D fuzzy topological relations between spatial objects and propose an efficient method for simulating relationships and extracting decision variables. This subject is applied for the application of "determining risk areas of Kuwait oil well air pollutions plumes on the southwestern forest areas of Iran". For this purpose, decision variables are extracted based on 3D fuzzy topological relations between air pollution plumes and a forest area, then, reasoned using defined proper rules in the knowledge base part of a spatial reasoning system. When smoke plumes move toward a forest area: data extractor extracts the smokes fuzzy areas form remote sensing satellite images, and topological simulator computes the strength and type of topological relationships and sends the extracted information to a designed knowledge based system. The final results show 20% improvement in reasoning results by adding inclusion index and 3D topological rations to the knowledge part of designed system.
Roozbeh Shad; Hamid Ebadi; Mohammad Sa'di Mesgari; Ali Vafaee Nejad
Abstract
Different industrial decision makers and managers in our country, try to select and organize locations for aggregating industrial units, estates and areas with respect to land use planning visions and industrial development strategies. In this regard, considering large quantity of the input data and ...
Read More
Different industrial decision makers and managers in our country, try to select and organize locations for aggregating industrial units, estates and areas with respect to land use planning visions and industrial development strategies. In this regard, considering large quantity of the input data and diverse criteria affecting this application, it is complicated and difficult to optimally make decision. Geographical Information System (GIS) is able to provide the decision-makers with appropriate tools for removing the difficulties and complexities of site selection process. For this purpose, spatial functions allow selecting an optimum site by using input maps through aggregated operators. These functions are categorized into various groups such as Boolean, Index overlay, Fuzzy logic, Genetic and Weighted evidence, with respect to their activities. So, it is essential to determine appropriate aggregated functions for designing and implementing an applied GIS for selecting optimum industrial estate. In this paper, first, conditions and factors influencing industrial estates site selection are determined and made ready for being entered into aggregated functions. Then, different properties of Index overlay, Fuzzy, Genetic and Weighted evidence models are evaluated for functional efficiency and output accuracy results. Finally, considering the results obtained from different stages, the appropriate model is determined and desirable user interface is developed. As a result of implementing, it was found that Index overlay model with 2.2 seconds time ratio and 5 positive efficiency is the best model for aggregating industrial estate site selection parameters as compared to Fuzzy, Genetic and Weighted evidence models.
Shirin Malihi; Hamid Ebadi; Farshid Farnoud Ahmadi; Mehdi Maboudi
Abstract
An important issue in implementation of a GIS system is preparation of data to be entered in GIS. To produce spatial data for GIS using photogrammetric techniques, conventional method is to apply photogrammetric and GIS systems individually (off-line procedure).
This approach is costly, time consuming ...
Read More
An important issue in implementation of a GIS system is preparation of data to be entered in GIS. To produce spatial data for GIS using photogrammetric techniques, conventional method is to apply photogrammetric and GIS systems individually (off-line procedure).
This approach is costly, time consuming and somehow unreliable due to the fact that 3D photogrammetric model is not available at the time of GIS data structuring, To overcome these problems, editing and structuring of spatial data can be carried out simultaneously during feature digitization.
Feature digitizing from photogrammetric models can be performed in an interface CAD environment by real time integration of photogrammetric and CAD systems. Based on this approach, generated data can be saved with standard structure and format defined by CAD environments (e.g., Micro Station)and directly used for GIS without further editing. In this paper, design and development of a software package called Object oriented CAD-Based Photogrammetric System (OCBPS2, version 2) which integrates Photomod and Micro Station systems in an object oriented way, is described. This system carries out real time structuring and editing of spatial data for class of road features by controlling logical relations among road class features and other features.
Mohammad Tale'i; Mohammad Sa'di Mesgari; Ali Sharifi
Abstract
This research is aimed at developing a model for measuring and comparison amount of supply and demand for different urban services from quality of life and equity perspectives, in urban built-up areas. This paper explains different steps of implementing the model as a tool for evaluating accessibility ...
Read More
This research is aimed at developing a model for measuring and comparison amount of supply and demand for different urban services from quality of life and equity perspectives, in urban built-up areas. This paper explains different steps of implementing the model as a tool for evaluating accessibility of residents to various services according to two main criteria: Land per capita and distance to services. In developing the model, geographic information system is used as a spatial planning support generator. The model has been tested in an urban area located in 7th regional municipality of Tehran, the capital city of Iran, and its result have been compared with outcomes of traditional techniques such as zoning. The results show that the model is effectively proper to clarify different levels of shortcoming in accessibility to urban land use services and improves accuracy of assessing the amount and location of the shortcomings. Developing such GIS-based micro-level evaluation model and presenting different approach regarding single-facility and multi-facility’s characteristics of urban services are the specific originality of this research.
Parham Pahlevani; Mahmoud Reza Delavar; Farhad Samad Zadegan
Abstract
Multi-criteria shortest path problems (MSPP) are called as NP-Hard. For MSPPs, a unique solution for optimizing all the criteria simultaneously will rarely exist in reality. Algorithmic and approximation schemes are available to solve these problems; however, the complexity of these approaches often ...
Read More
Multi-criteria shortest path problems (MSPP) are called as NP-Hard. For MSPPs, a unique solution for optimizing all the criteria simultaneously will rarely exist in reality. Algorithmic and approximation schemes are available to solve these problems; however, the complexity of these approaches often prohibits their implementation on real-world applications. This paper describes the development of a geospatial information system (GIS)-based genetic algorithm (GA) approach to MSPP on simple networks with multiple independent criteria. The GA approach is shown to explore the underlying network space, generate large candidate path sets, and evolve high quality approximations to the optimal MSPP solution(s) adequately.
