The overlay functions in Geographic Information Systems (GIS) are considered as one of the basic functions of these systems, and often, a variety of data stored in layers may be integrated together to generate new layers that contain useful informati
on for decision-makers. All geographic objects are stored in layers and usually rely on crisp set theory, whether, stored in a vector or raster format. In many cases, boundaries of classes or objects are not clearly defined, or when we perform classification of features into classes, the geographic objects located in the boundaries of classes could be classified into the wrong class. This research aims to develop overlay functions methodology based on fuzzy logic, reclassify the objects into fuzzy classes, and study the usability of this method to integrate data of specific phenomenon to help make optimal decisions. To implement and examine this idea, a set of Fuzzy Membership Functions was developed using the Python programming language embedded within the ArcGIS environment. Through this Fuzzy Membership Functions, the user can generate fuzzy sets and combine with each other according to one of fuzzy operations, and thus the generation of fuzzy sets allows supporting the right and reliable decision. To test the proposed fuzzy model capabilities, it has been applied in Tartous governorate to select suitable tourist facility sites in accordance with groups of factors. In summary, data integration using proposed fuzzy overlay functions can improve the reliability of data representation and thus the reliability of make the best decisions.
This research
aims to develop overlay functions methodology based on fuzzy
logic, reclassify the objects into fuzzy classes, and study the
usability of this method to integrate data of specific phenomenon
to help make optimal decisions.
Free and Open Source software (FOSS) is one of computer software, which source code can be accessed, freely used, modify, and distribute by anyone. It is produced by many of people or organizations, and distributed under licenses that comply with the
open source definition. This software has recently begun to play an important role in the academic and scientific research field, as in the professional field. In the past few decades, Geographic Information Systems (GIS) has seen very high growth rate, and this development included each of commercial and open source GIS software.
This research aims to show the great potential of Free and Open Source Geographic Information Systems (FOSS_GIS), and motivating to adopt it in developing countries, as a means to reduce licensing costs, promote local technological development through access to the source code and developing these systems. A case study is taken, in which we have tried to highlight the most important advantages of this software (i.e. FOSS_GIS), such as ease of implementation and good use, the ability to analyze and display of spatial data, professional maps production, and functionality emulator to commercial GIS software. The case study included the methodology of spatial suitability analysis, which is one of the main tasks of GIS; this methodology has been applied to choose the optimal site of urban project in Sheikh Badr area (Tartous Governorate) by proposing a set of general conditions. Using optimal site selection analysis of urban project helps to avoid the indiscriminate expansion and the irregular land-use. The free and open source software QGIS was used in this research, as well as the algorithms and tools of GRASS and SAGA softwares.
Key Words: FOSS_GIS, spatial analysis, QGIS, optimal site selection, Sheikh Bader area
