What is GIS?


As an emerging technology itself, the field of geographic information systems (GIS) is constantly evolving.  Over a span of twenty years, members of the geographic information community have seen this technology advance from command line, workstation-based software to tools that can now be used in the cloud and via mobile devices.

So, What is GIS?




GIS Versus Geospatial


Other quotes to answer “What is GIS?”





GIS has already affected most of us in some way without us even realizing it. If you’ve ever used an Internet mapping program to find directions, congratulations, you’ve personally used GIS. The new supermarket chain on the corner was probably located using GIS to determine the most effective place to meet customer demand.

Uses of GIS 

There are numerous ways in which GIS is used across different industries.  A few examples are:

  1. Emergency response teams normally use GIS when they want to collect logistics with regards to how they will move in times of natural disasters (see: Predicting Natural Disasters and Humanitarian Crises through GIS).

For more detailed articles highlighting how GIS is used in many industries visit:

A Short History of GIS

One of the most famous early examples of spatial analysis can be traced back to London in the year 1854 when Dr. John Snow was able to predict the occurrence of cholera outbreak (More: John Snow’s Cholera Map using GIS Data). Thanks to the study that Snow released, officials from the government were able to determine the cause of the disease; which was contaminated water from one of the major pumps. The map that Snow came up with was very interesting in that it had the capability of analyzing the phenomena relating to their geographical positions and this was the first time the world was witnessing this. Photozincography was developed in the earlier years of the 1900s and this enabled the maps to be divided into various layers as required. In the initial stages, the process of drawing these maps was lengthy since it involved free hand but this changed later on with the introduction of the computer.

John Snow’s 1854 Cholera Map.

The first GIS was created by Dr. Roger Tomlinson and then introduced in the early 1960s in Canada. During its inception, this system was mainly meant for collecting, storing and then analyzing the capability & potential which the land in the rural areas had. Prior to this, mapping by the use of computers was being used for such cases but this is a method that had numerous limitations associated to it. By the end of the 80s period, the use of GIS had already become popular in other related fields which is why it led to a spur in the growth of the industrial sector. Recently, designers came up with open source software for GIS so that the brilliant technology can be enhanced in a much simpler manner while being made available to all.

Learn more: History of GIS

Components of GIS

The next step in understanding GIS is to look at each area and how they work together.  These components are:

  • Hardware
  • Software
  • Data
  • People


Hardware comprises the equipment needed to support the many activities needed for geospatial analysis ranging from data collection to data analysis. For desktop GIS, the central piece of equipment is the workstation, which runs the GIS software and is the attachment point for ancillary equipment. The use of handheld field technology and mobile GIS is also becoming an important data collection tool in GIS. With the advent of web mapping, web servers have also become an important piece of equipment.


Different types of software are important. Central to this is the GIS application package. Such software is essential for creating, editing and analyzing spatial and attribute data, therefore these packages contain a myriad of geospatial functions inherent to them. Extensions or add-ons are software that extends the capabilities of the GIS software package. Component GIS software is the opposite of application software. Component GIS seeks to build software applications that meet a specific purpose and thus are limited in their spatial analysis capabilities. Utilities are stand-alone programs that perform a specific function. For example, a file format utility that converts from on type of GIS file to another. There is also web GIS software that helps serve data and interactive maps through Internet browsers.


Data is the core of any GIS. There are two primary types of data that are used in GIS: vector and raster data. A geodatabase is a database that is in some way referenced to locations on the earth. Geodatabases are grouped into two different types: vector and raster. Vector data is spatial data represented as points, lines and polygons.  Raster data is cell-based data such as aerial imagery and digital elevation models.  Coupled with this data is usually data known as attribute data.  Attribute data generally defined as additional information about each spatial feature housed in tabular format.

In a GIS, each piece of data contains a geographic location and attributes.

In a GIS, each piece of data contains a geographic location and attributes that describe it.  The red dot on the map is a Fortune 1000 company headquarter and the attributes are displayed in the information window.

Documentation of GIS datasets is known as metadata.  Metadata contains such information as the coordinate system, when the data was created, when it was last updated, who created it and how to contact them and definitions for any of the code attribute data.

There are many different ways that GIS data can be collected.  Head up digitizing (the process of tracing GIS data directly on the screen), LiDAR, drones, GPS, and satellites are some of the ways GIS data is created.

Layers of GIS Data

GIS data layers. Source: FCDC


Well-trained GIS professionals knowledgeable in spatial analysis and skilled in using GIS software are essential to the GIS process (More: Building a GIS Career). There are three factors to the people component: education, career path, and networking. The right education is key; taking the right combination of classes.  Selecting the right type of GIS job is important.  A person highly skilled in GIS analysis should not seek a job as a GIS developer if they haven’t taken the necessary programming classes.  Finally, continuous networking with other GIS professionals is essential for the exchange of ideas as well as a support community.

Further reading:

Article last updated: January 11, 2018. Article first written: November 12, 1999.  


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