What is GIS? A simplified explanation.
TL;DR — A Geographic Information System is an information system that specializes in the storage, retrieval and display of location data.
The standard definition of Geographic Information System (GIS) has been written for those who are conversant with GIS for years. This definition does not translate well to laypeople who simply want to know the meaning of the term and don’t seem to find one. Even seasoned GIS professionals fail to sufficiently explain the acronym to general audiences they interact with. Here’s an attempt hoping to provide the required clarity.
Information Systems
To understand the term Geographic Information System, drop the word Geographic and focus on ‘Information System’. An information system is a generic term to describe any system that manages information. An email service such as Gmail, Outlook or Yahoo, can be considered an Information System. This system stores emails, and upon request presents it as information to the user in rows of a table with functions to manage (compose, delete, reply, etc.) the emails. It can be said that an email service or email application is an information system specialized for emails.
Another example of information systems are travel booking websites such as Skyscanner, Expedia, Trivago and others. These information systems specialize in the retrieval of airline tickets, hotel reservations, car rentals, cruise ships etc. — providing the capability to use the information for a booking. In-fact almost all sites, platforms, apps and software can be imagined as Information Systems that specializes in a certain type or class of data.
And so, the GIS is just that, an Information System that specializes in managing Geographic data.
What is Geographic data?
The Geographic part of the term GIS represents locations in the form of coordinates — a pair of numeric values¹ that are also known as ‘latitude, longitude’ or ‘x,y’. The information system accesses stored coordinates and presents the data as an image drawn on the screen. The coordinates almost always represents locations on earth², which is why the term Geographic is used to describe these information systems. The result of rendering coordinates on a screen is a map that provides a differing perspective to the data available to organizations and people. It is important to mention here that GIS is a lot more than accessing coordinates and presenting a map, but this specific and unique mapping ability categorizes a software³ to be a GIS.
With all that said, here are various definitions of GIS, stated by organizations and sources which should now be a lot more clearer.
- GIS is a collection of computer-based tools for organizing information from a variety of data sources to map and examine changes on Earth. — by NASA
- A GIS is a framework for gathering, managing, and analyzing data. — by Esri
- GIS allows you to combine tabular data (e.g. spreadsheet sheet) with a geographic boundaries (e.g. maps). — by the QGIS Community
- A GIS, captures, stores, analyzes, manages, and presents data that is linked to location. — in the GIS Wiki
A GIS captures, stores, analyses, manages, and presents data that is linked to a location.
Additional clarity on generalizations
The explanation above generalizes certain ideas for ease of understanding. Here are few finer details for clarity.
¹A coordinate is a basic unit to identify a location and rarely exists by itself. It is usually associated with additional information (numeric values, dates, descriptions , images) and other coordinates to form data types such as points, lines, polygons, 3D objects, imagery, point clouds and many other representations of places, objects, assets and quantities to be presented on a surface.
²Locations in a GIS can also be above or below the earth’s surface, on another celestial object, a historical or a fictitious setting. But a overwhelming majority of GIS use cases are for data and information to be presented on the earth’s surface.
³The term ‘information system’ in this article was used to mean software. This helps to understand the uniqueness of GIS software, that is, to work with data referenced to a physical location on earth. However GIS is more than just its software component. It is a ‘system’ with four other components. a) The hardware or cloud infrastructure required by the GIS, b) the data made available through the GIS, c) the people skilled to use the GIS and d) the processes set in place to ensure the availability of new or updated content (data, maps, apps, tools) in a GIS.
