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Today nearly all cartography at the professional level is done on a computer. The maps in this book are an example of this. Special kinds of software are available that allow cartographers to make maps with a degree of speed, accuracy, and data management that were unimaginable three decades ago. These qualities have also served to make mapmaking a powerful tool for a variety of businesses and planners. And in that regard, the most significant, cutting-edge field in contemporary cartography is the geographic information system (GIS).

Giving you the complete lowdown on GIS would involve a lot of techo-babble that you don’t want to read and I don’t want to write. So perhaps the best way for me to describe GIS begins with a description of what it has replaced.

If you had poked around a city or regional planning office years ago, you’d be sure to find a huge table someplace with a huge base map that showed the streets and roads of the city or region in question. There would also be numerous overlays of different phenomena drafted on individual pieces of transparent film. For example, one transparent overlay might show the location of property boundaries. Others might show land use, sewage pipes, water mains, building characteristics, telephone lines, school districts, voting precincts, contour lines, wooded areas, and anything else that may be deemed useful for planning purposes.

Again, each characteristic would be on its own piece of transparent film — that is, its own map. So, if a planner wanted to see how two phenomena coincided geographically, the respective transparent films would be manually overlain on the base map and comparisons manually noted. Of course, the landscape changes. Thus, every so often a particular overlay would have to be manually updated or manually redrafted from scratch.

If all of this sounds a bit tedious, then you get the point.

With the advent of GIS, all of those physical base maps and pieces of transparent film have been replaced by layers of information that exist in computer memory (see Figure 5-8). This permits multiple layers, or even parts of layers, to be compared electronically, which is to say instantaneously. But the bottom line is that GIS has given geographers and planners the power to map and compare phenomena with great speed and accuracy. Indeed, remotely sensed images (I tackle that in the next couple of pages!) can be directly “fed into” a GIS, reducing to minutes and seconds a process of field observation and mapping that used to take weeks and months.

(© naschy / Adobe Stock)

FIGURE 5-8: Geographic Information Systems (GIS) use layers of locational and attribute data about places for analysis and decision-making.

The beauty of GIS is the ability to ask questions, or query, the various layers. Let’s say you want to locate a new grocery store. “Where” is a pretty important question. You might pull up a layer of population density, income levels, land for sale, established infrastructure such as sewers, competing grocery stores, and so on. Collectively overlain, each of these layers helps you to eliminate areas that don’t quite meet your criteria. The business applications are near endless, but think about what else we can do: Track disease! Establish school bus routes! Identify hurricane storm surge zones! It’s endless!

Most of you have probably not used a GIS, but you’ve come close. Whenever you use an online mapping service to find your way between two cities, you’ve had a simple GIS-like product at your fingertips. There’s a base map, there’s data — say restaurants or hotels — and you have the ability to “query.” Encoded into that map is not just locations but whether a street is one-way or not, and so on. As a result, your query about directions results in a selection of best paths for you to take, usually based on distance or time.

In the 1967 movie, The Graduate, moviegoers were told that the future is in plastics. Book mark this page now. The real future is in geospatial technology with GIS at the lead!