What is GIS – Definition?

What is GIS – Definition?

Geographic Information System (GIS) is a computer system build to capture, store, manipulate, analyze, manage and display all kinds of spatial or geographical data. GIS application are tools that allow end users to perform spatial query, analysis, edit spatial data and create hard copy maps. In simple way GIS can be define as an image that is referenced to the earth or has x and y coordinate and it’s attribute values are stored in the table. These x and y coordinates are based on different projection system and there are various types of projection system. Most of the time GIS is used to create maps and to print. To perform the basic task in GIS, layers are combined, edited and designed.

GIS can be used to solve the location based question such as “What is located here” or Where to find particular features? GIS User can retrieve the value from the map, such as how much is the forest area on the land use map. This is done using the query builder tool. Next important features of the GIS is the capability to combine different layers to show new information. For example, you can combine elevation data, river data, land use data and many more to show information about the landscape of the area. From map you can tell where is high lands or where is the best place to build house, which has the river view . GIS helps to find new information.

What is GIS- GIS Model

Gis Model

How GIS Works:

  • Visualizing Data: The geographic data that is stored in the databases are displayed in the GIS software.
  • Combining Data: Layers are combined to form a maps of desire.
  • The Query: To search the value in the layer or making a geographic queries.

Definition by others:

A geographic information system (GIS) lets us visualize, question, analyze, and interpret data to understand relationships, patterns, and trends. (ESRI)

In the strictest sense, a GIS is a computer system capable of assembling, storing, manipulating, and displaying geographically referenced information (that is data identified according to their locations). (USGS)

Advantage of GIS:

  • Better decision made by government people
  • Improve decision making with the help of layered information
  • Citizen engagement due to better system
  • Help to identify communities that is under risk or lacking infrastructure
  • Helps in identifying criminology matters
  • Better management of natural resources
  • Better communication during emergency situation
  • Cost savings due to better decision
  • Finding different kinds of trends within the community
  • Planning the demographic changes

History of GIS:

Modern GIS has seen series of development. GIS has evolved with the computer system. Here are the brief events that has happened for the development of the GIS system.

Year 1854 – The term GIS that used scientific method to create maps was used by John Snow in 1854. He used points on London residential map to plot outbreak of Cholera.

John Snow Cholera Outbreak Map

John Snow Cholera Outbreak Map

Year 1960 – Modern computerized GIS system began in year 1960.

Year 1962 – Dr. Roger Tomlinson created and developed Canadian Geographic Information System (CGIS) to store, analyze and manipulate data that was collected for the Canada Land Inventory (CLI). This software had the capacity to overlay, measurement and digitizing (converting scan hardcopy map to digital data). It is never provided in commercial format but Dr. Tomlinson is the father of GIS.

Dr. Roger Tomlinson (1933-2014)

Dr. Roger Tomlinson (1933-2014)

Year 1980 – This period saw rise of commercial GIS software’s like M&S Computing, Environmental Systems Research Institute (ESRI) and Computer Aided Resource Information System (CARIS). These all software were similar to CGIS with more functionality and user-friendliness. Among all the above the most popular today is ESRI products like ArcGIS, ArcView which hold almost 80 % of global market.

Component of GIS:

Hardware: Hardware is the physical component of the computer and GIS runs on it. Hardware may be hard disk, processor, motherboard and so on. All these hardware work together to function as a computer. GIS software run on these hardware. Computer can be standalone called desktop or server based. GIS can run on both of them.

Software: GIS Software provides tools and functions to input and store spatial data or geographic data. It provides tool to perform geographic query, run analysis model and display geographic data in the map form. GIS software uses Relation Database Management System (RDBMS) to store the geographic data. Software talks with the database to perform geographic query.

Data: Data are the fuel for the GIS and the most important and expensive component. Geographic data are the combination of physical features and it’s information which is stored in the tables. These tables are maintained by the RDBMS. The process of capturing the geographic data are called digitization which is the most tedious job. It is the process of converting scanned hardcopy maps into the digital format. Digitization is done by tracing the lines along the geographic features for example to capture a building you will trace around the building on the image.

People: People are the user of the GIS system.
People use all above three component to run a GIS system. Today’s computer are fast and user friendly which makes it easy to perform geographic queries, analysis and displaying maps. Today everybody uses GIS to perform their daily job.

Types of GIS Data:

Raster Data: Raster data store information of features in cell based manner. Satellite images, photogrammetry and scanned maps are all raster based data. Raster model are used to store data which varies continuously as in aerial photography, a satellite image or elevation values (DEM- Digital Elevation Model).

Raster Data:

Vector Data: There are three types of vector data, points, lines and polygons. These data are created by digitizing the base data. They store information in x, y coordinates. Vectors models are used to store data which have discrete boundaries like country borders, land parcels and roads.

Vector Data:

Advantage and Disadvantage of using raster and vector Data

  • Raster data model record value of all the points of the area covered which required more data storage than model represented by the vector model.
  • Raster data is less expensive to create computationally compare to vector graphics.
  • Raster data has issue while overlaying multiple images.
  • Vector data are easily overlaid, for example overlaying roads, rivers, land use are easier than raster data.
  • Vector data are easier to scale, re-project or register.
  • Vector data are more compatible with the relational database management system.
  • Vector file sizes are way smaller than raster image file sizes.
  • Vector data are easier to update like adding river stream but has to be recreated for the raster image.

Raster Formats

  • ADRG – ARC Digitized Raster Graphics
  • RPF – Raster Product Format, military
  • DRG – Digital raster graphic
  • ECRG – Enhanced Compressed ARC Raster Graphics
  • ECW – Enhanced Compressed Wavelet (from ERDAS
  • Esri grid –ASCII raster formats used by ESRI
  • GeoTIFF – TIFF variant enriched with GIS relevant metadata
  • IMG – image file format used by ERDAS
  • JPEG2000 – Open-source raster format
  • MrSID – Multi-Resolution Seamless Image Database

Vector Formats

  • AutoCAD DXF –AutoCAD DXF format by Autodesk
  • Cartesian coordinate system (XYZ) – simple point cloud
  • DLG – Digital Line Graph (USGS format)
  • GML – Geography Markup Language – Open GIS format used for exchanging GIS data
  • GeoJSON – a lightweight format based on JSON, used by many open source GIS packages
  • GeoMedia – Intergraph’s Microsoft Access based format for spatial vector storage
  • ISFC – Intergraph’s MicroStation based CAD solution
  • Keyhole Markup Language KML – Keyhole Markup Language a XML based
  • MapInfo TAB format – MapInfo’s vector data format
  • NTF – National Transfer Format
  • Spatialite – is a spatial extension to SQLite,
  • Shapefile – Most popular vector data developed by Esri
  • Simple Features – specification for vector data
  • SOSI – a spatial data format used for all public exchange of spatial data in Norway
  • Spatial Data File – Autodesk’s high-performance geodatabase format
  • TIGER – Topologically Integrated Geographic Encoding and Referencing
  • (VPF) – Vector Product Format

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This Post Has 52 Comments

  1. Gis at a finger tip,so interesting.

    1. Thank you Dauda, appreciate for your comment

  2. Good Initiative. Carry on plz

    1. Thank you Suman, appreciate for your comment

  3. very educative lesson,develop more!

    1. Thank you Yakubu, appreciate for your comment

  4. Thanks for the article. It was very usefull.

    1. Thank You.

  5. Hello!,

    I am a Student, learning GIS, and I ASK THAT PLEASE email me back, AND SEND ME SOME INFORMATION, ON HOW GIS IS USED IN THE AREA OR FIELD OF Environmental Design? I AM LOOKING FOR A CAREER JOB, THAT USES GIS, AND IF YOU CAN EVEN MAIL ME SOME INFORMATION ABOUT ENVIRONMENTAL Design, The organization called: EDRA.ORG, I WOULD APPRECIATE IT MICH. I LOOK TO YOUR REPLY.

    Thank you
    William Eric Huggins
    P.O. Box 96
    Randallstown, Md. 21133

    1. I will send u in your mail box.

  6. Hi Admin!

    I am very pleased for you helpful and supportive materials concerning GIS and I would kindly ask you to send me via my email address.
    I actually appreciate and recognize your valuable learning materials.

    Sorry, I would like to know how can geophysical,geological,geochemical and magnetic datasets can be combined in GIS to yield effective decision making process?

    Please, assist me.

    Best regards,
    Amir.

  7. Thanks Admin for your strong cooperation!

    I am waiting for your assistance and it is my hope that the issues will be definitely resolved.

    Thanks very much.
    Amir.

  8. Hello !

    I am just to remind you on the issues that I had told you yesterday.

    Good Day,
    Amir.

  9. Hi….. I am university student… I read about GIS a few days ago… Now I decided to read it properly and want to do some research work on it…. So plz guide me regarding this……

    Abdul Ghaffar
    Sialkot, Pakistan

    1. Let me know what you are looking for?

  10. Really awesome site
    Thanks for great information
    #rock.n roll****.

    1. Thank you Jemika

  11. Please what is the use of “like” ,”in” ,”is” ,”null” ,”like” and “not” related to select by attributes in the selection word

  12. Hii……

    I get to know this is one of the useful and helpful site by guidance.
    If there is a possibility can you help me with this…
    I’m interested to get internship on GIS ,so can you please help with this……

    harsha,
    INDIA.

    1. Yes tell me what type of help you are looking for?

  13. Tnx for ur website

    1. Thank you Mensah

  14. Great Information ????????

  15. important topic to study

  16. important topic to study,just do more inventions on it.

  17. my name is Khalid Jamal, Iam a student at the institute of rural development planning Tanzania bachelor degree my course is bachelor degree of regional planning. I ask about the application of GIS in settlement planning.

  18. what are the application of GIS in settlement planning

  19. Good day please am an environmental geology student, I would like to know if GIS could be used to assess groundwater, if its possible, how could that be achieved, i want to do a research on how gis and remote sensing could be used to assess groundwater potential and quality

  20. Thankyou so much

  21. Hi sir, thanks for you benefit us information about GIS, am student and your lessons can help me to understand whats GIS , so really i like it the easiest way that you have prepared GIS, so can u plz send pdf book at my email address about this GIS you have prepared, now am waiting for your reply
    Thank you
    William Eric Huggins

  22. really educative

  23. I am a Student MSC, learning GIS, and I ASK THAT PLEASE email me back, AND SEND ME SOME INFORMATION, ON HOW GIS IS USED IN THE AREA OR FIELD OF Environmental Design? I AM LOOKING FOR A CAREER JOB, THAT USES GIS, AND IF YOU CAN EVEN MAIL ME SOME INFORMATION ABOUT ENVIRONMENTAL Deign. I LOOK TO YOUR REPLY or answer

    1. GIS has lots of opportunity, I myself works in the field. Imagine everything in this world has location and information available get attached to x and y.

  24. Dear admin
    First time I know about GIS when I attended a meeting regarding disaster and risk management organization. We need this tools for evaluation of certain areas. Could you please send me info on how or application tutorial of gis on how it used in environmental mapping.
    Thank you very much.

  25. what is geographic query

  26. Good day, thanks for your detailed explanation on GIS, as an HSE officer I will like to know how I can make use of GIS in Planning, Monitoring and Enforcing issues of Health, Safety and Environment in Oil and Gas Company. Please Help.

  27. Actually I am taking GIS class for Petroleum Engineering students. and It is basic introduction of GIS. In this comment i will add the syllabus. kindly send back the materials.
    UNIT I FUNDAMENTALS OF GIS 9
    Introduction to GIS – Basic spatial concepts – Coordinate Systems – GIS and Information
    Systems – Definitions – History of GIS – Components of a GIS – Hardware, Software, Data,
    People, Methods – Proprietary and open source Software – Types of data – Spatial, Attribute
    data- types of attributes – scales/ levels of measurements.
    UNIT II SPATIAL DATA MODELS 9
    Database Structures – Relational, Object Oriented – ER diagram – spatial data models – Raster
    Data Structures – Raster Data Compression – Vector Data Structures – Raster vs Vector Models-
    TIN and GRID data models – OGC standards – Data Quality.
    UNIT III DATA INPUT AND TOPOLOGY 9
    Scanner – Raster Data Input – Raster Data File Formats – Vector Data Input –Digitiser –
    Topology – Adjacency, connectivity and containment – Topological Consistency rules –
    Attribute Data linking – ODBC – GPS – Concept GPS based mapping.
    UNIT IV DATA ANALYSIS 9
    Vector Data Analysis tools – Data Analysis tools – Network Analysis – Digital Education models –
    3D data collection and utilisation.
    UNIT V APPLICATIONS 9
    GIS Applicant – Natural Resource Management – Engineering – Navigation – Vehicle tracking and
    fleet management – Marketing and Business applications – Case studies.

  28. thanks alot lvery hapy with your honorableresponse

  29. thanks a lot. this is very informative

  30. I need five different definition of gis, years if the defined and names if the defined

  31. hi
    I’m a specialized student in geography .and im studing GIS and im working with QGIS.This is so important and thanks for this informations.i would like to tell you , can you made some note of ‘how to work in GIS.’
    Thank you
    R.G.Nipunie Rajasekara
    Kandy,
    Sri Lanka

  32. Hi This is Mohan Reddy, from India.
    I continue my job in Gis industry past 2 years, I want know please, how to get Gis professional certificate?.
    this is help foe my future, is there any institutes in India, please let me know.

    Thank you,
    Best regards,
    Mohan Reddy

  33. सभी GIS उपयोगकर्ताओं के लिए फायदेमंद है क्योंकि यह समझाने में पूर्ण रूप से सक्षम है

  34. Hi!! I am claude , a student learning applied statistics and i would like to ask you some question related to GIS how GIS can be used in statistics and if if possible you should send me on my email a prepared well note on that question and olso the application of GIS in statistics and related video teaching about GIS

    Thanks regard
    jean claude Mugiraneza

  35. I have really learned a lot, i am currently doing my MSc in GIS and this website has provided me with much information i need.

    1. Thank you

  36. Hi,
    May I know the relevant example of data issues in GIS?
    Thank you.

  37. I’m interested to learn more about GIS, it’s very brilliant technology.

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