Tuesday, August 4, 2009

What is GIS?

Okay so here’s a good topic to start my blog with: What is GIS? How do you really define and explain it to someone who doesn’t know what it is?

As a Geospatial Analyst I know the ins and outs of GIS, as I use it in my job every day. Though I’m not so sure you’d get that from me if you heard me try to explain what GIS is to someone who has never heard of it before. Instead of giving a brief, understandable definition of GIS, I find myself painfully stuttering through what ends up becoming a boring, broken monologue to which I eventually receive a blank stare. This is the point at which I usually just awkwardly stop talking, as I end with “Yeah…it’s just kinda hard to explain”.

Here’s my problem: GIS is so broad of a topic and so powerful of a tool, I want people to understand and RECOGNIZE its capabilities. So instead of explaining it at a high level, I find myself overwhelmed trying to figure out how I can briefly explain all of the capabilities and applications of GIS to someone who probably doesn’t know much about databases in general – let alone spatial databases. After talking to my fellow GIS geek friends, this seems to be a pretty common problem among all of us in the GIS field – explaining what it is that we do every day. So, I’ve put together some thoughts on best practices for approaching this topic and explaining what GIS is at a high level.

First tip: You’re never going to be able to briefly explain GIS to someone in a way that they will be able to understand its power and applications if they have never used it before – don’t waste your time or theirs with details.

Okay, so what IS GIS anyway? *At a high level*, GIS is a combination of a few things:
1. Hardware: workstations, servers, and handheld devices for collecting and storing spatial data.
2. Software: GIS application for viewing, analyzing, and transforming spatial data.
3. Spatial data: data with a geographic location.
4. People: analysts well-trained in spatial analysis and skilled in using GIS software.

Let’s practice. Someone asks you, “What is GIS?”. Instead of stuttering your way through the details, you calmly and collectively say:

“GIS stands for Geographic Information Systems. It’s a computer-based system for collecting, viewing, analyzing, storing, and transforming spatial data, or data with a geographic location.”

You might want to give a *few* descriptive examples, so that people have a better idea of what you are talking about. So here are some applications of GIS with examples that you may want to mention:

  • Commercial: Use spatial models and geodemographics to target markets and improve profitability.
  • Law Enforcement: Use incident mapping and spatial statistics to analyze crime.
  • Transportation: Collect roadway pavement conditions to determine funding and plan pavement schedules.
  • Utilities: Model electric networks to determine customers effected by power outages.
  • Logistics Management: Vehicle routing for school buses, delivery services, emergency vehicles, etc.
  • Environmental: Locate ideal habitat locations for studying wildlife.

So there you have it – my very own simplified explanation of GIS. Post a comment or shoot me an email if you have another definition. I could throw a list of good definitions together for a later blog.


  1. Great job! Thanks for taking the time out and providing so many examples. Its hard to capture all that GIS is, you put forth a great effort. If interested there is some more info at: www.gis.com/whatisgis

    and additionally a white paper "Geography Matters" at: www.gis.com/whatisgis/geographymatters.pdf

  2. Thanks for your post, G! Also thank you for providing additional sources. I like the way www.gis.com/whatisgis defines GIS by describing the "three views": This kind of goes along with my own defintion where spatial data is stored in the Database View, viewed and analyzed in the Map View, and transformed in the Model View. Another great way to look at/explain GIS!

  3. Good blog.. I wish I had the time to do something similar..

    Ever come across a way to perform a spatial join between two polygon layers based on max area?? (i.e. weighted area spatial join)

    Man I wish ESRI would build more useful functionality into Arc.

  4. Hi Jeff. That's a good question. Can you describe what you're trying to do in more detail?