What are Geographic Information Systems (GIS)?

No seriously… what is it?

The best definition of GIS that I found was actually from the University of Wisconsin-Madison, “A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of geographical data. The key word to this technology is Geography — this means that some portion of the data is spatial. In other words, data that is in some way referenced to locations on the earth.” In even simpler terms its software used to store, visualize, analyze, and interpret geographic data. The “store” aspect is referring to large database tables full of information and the “visualization” aspect is simply referring to maps. The data is usually brought in by layers and from various sources where it is aggregated into one system, the GIS.

Data layers in a sample GIS system

What is it used for?

Well, the obvious answer is analyzing data, but what kind of data? And what is that data used for? It really depends on the industry in which GIS is being utilized. Here are a few:

  • Real Estate — Land parcels, Market prices by region
  • Education — Academic performance by region
  • Health — Tracking the spread of a deadly virus 🙄
  • Insurance — Risk probability by region
  • Public Safety — Real-time situational data for first responders
  • Transportation — Traffic patterns, Mapping your commute routes
  • Government — Population, mapping of congressional districts
  • Sustainability — Display areas where humanitarian assistance is needed
GIS system tracking confirmed COVID-19 Cases

How did it come about?

One of the most famous early examples of spatial analysis can be traced back to London in the year 1854 when Dr. John Snow (no not the one that is King of the North) was able to predict the occurrence of the cholera outbreak. 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.

John Snow’s Cholera Map

How does it work?

Tech’s role in GIS

The heart of a modern GIS system is indeed software. You will need databases to hold the data, a backend to process that data and perform analysis, and a frontend to visualize the data and the analysis results. Luckily, Software Engineers are a generous and caring group so many things are open source. Here are a few open-source tools used in GIS:

  • OpenLayers — Open source Javascript library for displaying map data in web browsers.
  • Leaflet.js — Open source Javascript library used to build web mapping applications.
  • PostGIS — Open source software that adds support for geographic objects to a PostgreSQL database.
  • SpatiaLite — Open source extension that provides vector geodatabase functionality for SQLite databases.

The Wrap-Up

GIS has become more and more of an essential tool as time passes and its industry is growing with it. GIS tech companies will continue to grow, making the capabilities of GIS grow, making the chances of discovering world-changing data grow. I hope you enjoyed reading this as much I did writing it!



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Stephen Anderson

Stephen Anderson


Hi, I’m Stephen! I’m a Software Engineer just trying to help people through applications that make the world better. Check me out at stephenanderson.dev.