Geographical information system: Definition and components Prince Mohan Assistant Professor, Dept. of Geography, GDC Theog-171201 e-mail. prince88hpu@gmail.com

Father of GIS Dr. Roger Tomlinson (1933-2014) Dr. Roger Tomlinson (1933- 2014) is recognized as the "father of GIS.” He was the visionary geographer who conceived and developed the first GIS for use by the Canada Land Inventory in the early 1960s. Dr. Roger Tomlinson (1933-2014)  Source: Downloaded from Google

What is GIS ? The acronym GIS stands for Geographic Information System which consists of three words, viz. Geographic, Information and System. The word ‘Geographic’ deals with spatial objects or features which can be referenced to a specific location on the earth surface. The word ‘Information’ deals with the large volume of data about a particular object on the earth surface. The term ‘System’ is used to represent systems approach where the parts of complex environment is considered to form an integrated whole for managing and decision making. GIS is an integrated system of geography and information tied together. Other related terms used for GIS are: LIS: Land Information System GIS: Geo Information System SIS: Spatial Information System Geographic Position + Information System Source: Downloaded from Google

Definition Geographic Information System (GIS) is defined as an information system that is used to input, store, retrieve, manipulate, analyze and output geographically referenced and associated attribute data in order to support decision making for planning and management of land use, natural resources, environment, transportation, urban facilities, health services so on. Source: Downloaded from Google

Basic GIS Functionalities Four main Functions: Data Input (e.g., scanning, digitizing, data entry etc.) Data Management (data storage and retrieval, etc.) Data Manipulation and Analysis (e.g. editing, data conversion, data integration, overlay, buffering, proximity, network functions etc.) Data Output (e.g. map making, printing, etc.)

Patterns- Which things are related…? Models- What if…? GIS Use Locations- Where is…? Objects- What is at….? Patterns- Which things are related…? Models- What if…? Trends- What has changed since…?

Source: Downloaded from Google COMPONENTS OF GIS Source: Downloaded from Google Source: Downloaded from Google

COMPONENTS OF GIS Hardware Contd… Hardware Hardware is the computer on which the GIS software operates. Today, GIS runs on a wide range of hardware types, from centralized computer servers to desktop computers used in stand-alone or networked configurations. Key hardware components are: Data Input- Scanner, Keyboard, Digitizing Table Processing- CPU Storage- Hard Disks (both internal and external) Data Output- Visual Display Unit, Printer, Plotter Hardware Software Source: Downloaded from Google

COMPONENTS OF GIS Software Contd… Software Software is program which runs in computer machine. It provides the functions and tools needed to store, analyze, and display geographic information. Key software components are: DBMS (database management system) Tools for the input and manipulation of geographic data Tools that support geographic query, analysis, and visualization GUI (graphical user interface) for easy access to tools GIS software are either commercial software or developed on Open Source domain, which are available for free. However, the commercial software is copyright protected, can be expensive and is available in terms number of licensees. Currently available commercial GIS software includes Arc/Info, Intergraph, MapInfo, Gram++ etc. Out of these Arc/Info is the most popular software package. And, the open source software are QGIS, AMS/MARS etc.

COMPONENTS OF GIS 3. Data Contd… Source: Downloaded from Google The most important component of a GIS is the data. Two types of data used in GIS are collected from two types of data sources. Geospatial data and related tabular data can be collected from Primary Sources (field survey) as well as Secondary Sources (bought from a commercial data provider). Geo-Referenced Data (geo-spatial data) are in the form of maps. The sources of geospatial data are digitized maps, satellite images and aerial photographs. These data forms must be properly geo-referenced. Attribute Data (tabular data) are in the form of tables, and are in some way related to geospatial data. Digital maps are the basic data input for GIS. Tabular data related to the map objects can also be attached to the digital map data. Most GIS software comes with inbuilt Database Management Systems (DBMS) to create and maintain a database to help organize and manage data. Source: Downloaded from Google

COMPONENTS OF GIS 4. People 5. Methods GIS technology is of limited value without the users who manage the system and develop plans for applying it. There must always be people to plan, implement and operate the system as well as to make decisions based on the output. Source: Downloaded from Google Source: Downloaded from Google GIS users range from technical specialists who design and maintain the system to those who use it to help them do their everyday work. GIS projects range from small research applications, where one user is responsible for design, implementation and output, to International corporate distributed systems, where different types of users interacts with the GIS in many different levels and ways. 5. Methods A successful GIS operates according to a well-designed plan and business rules, which are the models and operating practices unique to each organization.

Benefits of GIS Geospatial data are better maintained in a standard format. Revision and updating are easier. Geospatial data and information are easier to search, analysis and represent. More value added product. Geospatial data can be shared and exchanged freely. Productivity of the staff improved and more efficient. Time and money are saved. Better decision can be made.