What *IS* GIS?

It seems like a simple question. It should be pretty easy to answer.

You’re a GIS professional. You’ve been around the technology for years, and you use it every day. You present your work at conferences and leave with a stack of business cards from like-minded geogeeks. You and your peers have lengthy discussions about the finer points of isolines and your latest adventures in kriging over burritos at lunch. But you struggle when a friend, neighbor, spouse, sibling, grandparent, or child asks:

“What is it exactly that you do?”

Why GIS, of course! Which is inevitably followed by a quick:

“What IS GIS?”

There are at least as many definitions of GIS as there are GIS professionals. Perhaps you’re an old school paleogeographer and prefer a classical definition:

“GIS is a tool that can access, integrate, and distribute layers of map information. The five parts of a GIS include hardware, software, data, procedures, and people.”

Ah, yes! Who can forget the “five parts of a GIS”? And layers! Layers are the reason we’re all employed! Thank you, Ian McHarg!


GIS and layers: like peanut butter and chocolate.

But maybe you prefer a little more modern definition:

“GIS lets us visualize, question, analyze, interpret, and understand data in new ways. This can reveal relationships, patterns, and trends.”

It might be easier for some people to understand what GIS is if you first gave it some context:

A transformation is taking place. Businesses and government, schools and hospitals, nonprofit organizations, and others are taking advantage of it. All around the world, people are working more efficiently because of it. Information that was limited to spreadsheets and databases is being unleashed in a new, exciting way—all using GIS.”

Or perhaps it’s easier for you to describe GIS in terms of a simple workflow:

People intuitively understand maps. When a decision needs to be made, GIS helps us gather information and place it on a digital map. We then use GIS to evaluate the decision geographically. Once we fully understand the geographic consequences of the decision, we can act in an informed, responsible manner.”

Maybe you prefer to talk about GIS in terms of the types of questions it can answer:

“Where are my customers and potential customers? Which areas of my town are most vulnerable to natural disasters? Where should we locate a new elementary school? GIS can help answer questions such as these by combining data from many sources and producing customized maps.”

Some people find it more effective to communicate GIS as a value proposition, in terms of the benefits it can bring to an organization:

GIS benefits organizations of all sizes and in almost every industry. There is a growing interest in and awareness of the economic and strategic value of GIS.  The benefits of GIS generally fall into five basic categories:

  • Cost savings resulting from greater efficiency
  • Better decision making
  • Improved communication
  • Better geographic information recordkeeping
  • Managing geographically”

Or do like to take more of a philosophical approach?

“Remote sensing satellites and earthbound sensors are providing us with vast amounts of new data about our planet.  With the availability of easy-to-use GIS tools to display and analyze this data, now everyone can be geographer. This has far-reaching benefits to both society and the environment, ushering in a new era of understanding our world.”

Sometimes, depending on who is asking the question, your only hope at getting anything other than a blank stare may be an overly-simplistic definition, even if it loses some of the most important characteristics of what GIS does:

“GIS is computer software that makes maps.”

My personal favorite definition, at least this week, is:

GIS helps us see where things are—and decide where they should be.”

Or maybe the “father of GIS” was right when he said:

“A simple definition is not sufficient.”
Roger Tomlinson

The truth is, millions of people use GIS, and there are almost as many definitions of GIS as there are people who use it.

So, I ask you:

“What is it exactly that you do?”

“What IS GIS?”