GIS is commonly known as Geographic Information System. It is a set of tools for collecting, storing, retrieving, transforming, and displaying spatial data from the real world for a particular purpose. (Burrogh,1986). It is a computer system consisting of hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display all forms of geographically referenced information
Importance of GIS
- Map making.
- Improved decision-making with the help of layered information.
- Cost savings due to better decisions and increased efficiency.
- Helps to improve communication between any involved organizations as the visual format is easily understood by all.
- Easy recordkeeping.
- Better management of natural resources
- Finding different kinds of trends within the community.
- Managing geographically.
Components of GIS
GIS integrates five major components;
1. Hardware Components
Hardware is a computer within which the GIS data and computer software applications are stored and accessed. There are different types of hardware available nowadays which are server-based or desktop. The components of hardware are:
- Motherboard: It is the board where major hardware parts are installed.
- Hard Drive: Also called hard disk, place to store data.
- Processor: It is called a Central Processing Unit (CPU), and performs calculations.
- RAM: Random Access Memory (RAM) where all running programs load temporarily.
- Printer: It is an output device used to print images, maps, or documents.
- External Disk: These are portable storage spaces such as USB drives, DVDs, CDs, or external disk.
- Monitor: It is a screen for displaying output information.
2. Software Components
It provides tools to run, edit and display spatial information. Key GIS software applications include the DBMS(Database Management System, GIS tools for the input and manipulation of geographic information, and a graphical user interface (GUI) or dashboard, query tools, and layout.
Some of the software used in GIS are:
- Commercial– ArcView, ArcGIS/ArcInfo, GRASS, MapInfo, IDRIS, etc.
- Open Source– ILWIS, MapWindow, QGIS, Saga GIS, etc.
It is the most important component of GIS, also known as the heart of GIS. There are two basic data types:
- Spatial data: Spatial data can be either collected or purchased from the commercial data provider. It refers to real-world geographic objects such as streets, buildings, forests, river, and their respective locations. These can be represented in the form of vector data (points, lines, and polygon features) or raster also known as image data (grid form)
- Attributes (tabular) data. . Attribute data describes the characteristics of spatial features data such as a name, area, perimeter, depth, or population.
By integrating spatial data with related attribute data we analyze, solve and visualize the related data.
People are the most fundamental component of GIS, without whom GIS will be of limited value, as people are involved in all phases from the development of GIS to collecting, uploading, manipulating, and analyzing data. GIS users can operate in groups or individually. Individuals may be GIS managers, analysts, technicians, or users. All should have the basic knowledge to work with geographic data.
GIS operates with a well-designed plan, business operational rules, and methods, which are models and operating practices. The methods may vary with different organizations. These methods answer the question to be resolved. Include how data will be entered, stored, managed, retrieved, transformed, analyzed, and presented in the form of output.
Functional Elements Of GIS
There are five functional elements of GIS acting as a guiding principle for the analyst to develop an end-to-end model.
- Data Acquisition – It refers to the identification and collection of the required data. It covers every step involved in converting data obtained from field observations, sensors, and already-existing maps into a compatible digital format.
- Preprocessing – It involves the manipulation of data in several ways so that it can be stored within the GIS database and the establishment of a consistent system for data recording.
- Format conversion such as geo-referencing. (i.e. converting GPS points into feature classes),
- Error detection and editing, edge matching, and tiling,
- Merging of points into lines and lines into a polygon,
- Merging data storage and database management.
- Rectification/registration, interpolation and photo-interpretation.
- Data Management – It provides consistent methods for data entry, update, deletion, retrieval, and security using a Database Management System (DBMS) should indicate the way in which data about the position, topology, and attributes of geographical elements (such as points, lines, areas and more complex entities representing objects on the earth’s surface) are structured and organized.
- Manipulation and Analysis – It involves working within databases to derive new information using several basic and advanced tools. This subsystem transforms spatial data, for example from one entity type (points, lines, and areas) to another, and performs the spatial analysis. It is related to geo-referencing.
- Data Output – The data are displayed and the result of the analysis is reported to the users in various ways such as statistical reports, maps, graphics, tables, etc. which may be hardcopy or softcopy.