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    • What is GIS?

    What is GIS?


     What is Geographical Information System?

    Geographical Information System (GIS) is identified in different forms due to the different users in different disciplines. Especially in the world, users concern with the spatial information make a sensation between institutions and organizations, rapid changes in the developments don’t allow to make standard definitions of GIS. GIS is qualified according to the some researchers, contains all of the spatial information systems and examine the scientific concept of geographical information whereas some researchers believe that spatial data structure brought a digital computer-based tool and the others, database management system that helpsthe organizations.







    Accordingly, the most common form of description of GIS as follows;


    “Geographical information system is the information system that performs collection, storage, processing and presentations with graphic and non-graphic information to the users.”

    Components of GIS

    There are five basic components of GIS. These are;

    a)Hardware:It is identified that computer making GIS possible to process and computer related the side of the whole products. In the whole systems, computer appears the most important equipment, but some of the side equipments are also needed. For example, printer, plotter, scanner, digitizer and collector. These are the most important equipments of GIS. Today, there are many GIS software running on different hardware. There are so many different devices such as centralized computer systems, desktop computers, personal computers, network (network) equipped computer systems.

    b)Software:This is a high-level programming language algorithm that provide storing, analyzing and viewing of geographical information to the users. Some of the basic elements that should be in the geographical information system software as follows;

    Possession of necessary tools for geographic data and data input/data processing.

    Having a data base management system.

    Supporting spatial query, analysis and visualization.

    c)Data: This is the most important component of GIS. As graph structure of geographic data and identifier  character of attribute or table data is collected from necessary resources, the data is ready on the market can also be purchased.GIS combine spatial data with other data sources. Thus, data from many institutions and organizations are incorporated with spatial data. While the data is considered to be the basic element for GIS specialists, it is thought  the most difficult component to be obtained . Clutter data sources, numerous and diverse structures requires great time and cost for collecting these datas. 

    d)People: GIS technology without people would have a limited structure. Because people operate necessary systems that are implemented some problems in the real world and prepare developments plans.GIS users are comprising of expert technicians design and maintain systems. So people use these systems to improve their  daily performance.

    e)Methods:A successful GIS works great designed plan and business rules. This type of institutions provide functions  the form of model and applications to the each positional information flow efficiently between institutions of GIS necessary rules ,methods need to be developed and implemented.

    How is GIS Works?

    GIS stores information about the earth recognizing the thematic map layer are associated with each other. This is simple but extremely powerful approach for evaluating spatial data. This approach provide solving some real world problems for example, modeling of changes in atmosphere ,recording details of applications based on planning.

    Geographical references:

    Geographical information contain the exact values such as the form of latitude-longitude geographical coordinates or national coordinates or contain reference information  identified address, region name and path name. This geographical references provide positioning of objects, placement a known position coordinate. Thus, commercial regions, lands, forest areas, movements of the earth crust and analysis of surface shapes are determined  depending on the location. There are two different spatial data models; vector and raster data models.

    Vector Data Models:

    In this model; point, line and polygons (x,y) are stored with coded values of the coordinate. While an electricity pole that point feature is identified a single coordinate (x,y) road that features a line are stored as a series of coordinates. Polygons for example parcel, building, land areas are stored as closed shapes that have the same coordinate in the start and the end of polygon (x,y).

    Raster Data Models:

    Raster data model usually are used in the continuity of geographic feature. Raster image is formed to a combination of structure adjacent grid cells. Each cells is also known as pixel. Raster models capable of photo image usually can be obtained by scanning photographs or maps. One of the vector and raster data models usually used in preference to GIS application format. But, nowadays, each model simultaneously can be used. This uses is known as hybrid data model in GIS.

    The Basic Functions of GIS:

    Data collection

    Data management

    Data processing

    Data presentation

    1)Data collection: Geographical data are collected and converted the digital format before using in  GIS. Transformation data from mapping or paper stage to the computer stage is known as digitizing process. In the modern GIS technology these types of transactions materialized with automatic tools using scanning technique in the large-size projects. In the small-sized projects, digitization can be done manually using table type digitizers. Nowadays, many geographic data are readily available in the market in a compatible GIS format. They are directly transmitted to the system by providing manufacturer companies.

    2)Data management:In the small-sized projects, geographical data is possible to be stored in the limited size of simple files. But, Data Base Management System helps that  being broad and comprehensive volumes of data and also,using, storing, organizing and operating of multiple data sets. Data Base Management Systems is one of the computer program and operates and combines the databases. There are a lot of designed structure database management systems, but the most useful for GIS is relational database system. In this system, data are kept in computer memory according to the structure of thought.

    3)Data proccessing:In some cases, for specific GIS projects conversion and evaluating of data types to each other or may be asked. It is required that the data can be compatible with the system. For example, spatial information may be presented in different scales. ( esc. Road data 1/100.000, population distribution data 1/10,000 , building data 1/1000 ). All of this information converted to the same scale before it is incorporated. This transformation  may be continuous and permanent  for an analysis process.GIS provides information both  simple query capacity with clicking the cursor (mouse) on object on the computer  and for managers and researchers with multi-faceted spatial analysis tools in the desired process. GIS technology is no longer has begun to examine geographic data in the form of statistical charts and  "If you happen .." (if conditions) in the form of logic queries and scenarios. In GIS technology, any kind of data can be treated in many geometric and logical process thanks to the software  questioning and analysis of spatial data.

    4)Data presentation: Image processing is an important function for CBS. At the end of many geographic  transaction, results  are made visual map or graphic representations. Maps are the best possible communication tools between the user and geographic information. Although cartographers have produced map for many years, GIS provides new and more effective means which has contributed to the rapid development of the science of cartography. Maps can be combined with written reports, three-dimensional representations, photos, images and multi-media (multimedia), and variety of other output.

    Applications of GIS:

    Nowadays, GIS technologies have been applied to diverse fields to assist experts and professionals in analyzing various types of geospatial data and dealing with complex situations. No matter in business, education, natural resources, tourism, or transportations, GIS plays an essential role to help people collect, analyze the related spatial data and display data in different formats. Many common application areas of GIS are:

    scientific research,

    resource management, 

    asset management, 

    infrastructure (gas, electricity, water),


    environmental impact assessment,

    landscape architecture,

    urban planning, 



    geographic history, 



    mineral mapping, 


    military applications,

     air, sea and land traffic monitoring vehicle tracking systems,


    search and rescue,

    determination  of cultivated agricultural fields and calculation of the total crop.