Web Mapping Illustrated

Chapter 1. Introduction to Digital Mapping

Not long ago, people drew and colored their maps by hand. Analyzing data and creating the resulting maps was slow and labor intensive. Digital maps, thanks to the ever-falling cost of processing power and storage, have opened up a whole new range of possibilities. With the click of a mouse or a few lines of code, your computer analyzes, draws, and color-themes your map data. From the global positioning system (GPS) in your car to the web site displaying local bus routes, digital mapping has gone mainstream.

Of course, learning to produce digital maps requires some effort. Map data can be used incorrectly, resulting in maps with errors or misleading content. Digital mapping doesn't guarantee quality or ethics, just like conventional mapping.

The Power of Digital Maps

When you contrast the methods of conventional and digital mapping, the power of digital mapping becomes evident. The process of conventional mapping includes hand-drawn observations of the real world, transposed onto paper. If a feature changes, moves, or is drawn incorrectly, a new map needs to be created to reflect that change. Likewise if a map shows the extent of a city and that city grows, the extent of the map will need to be changed and the map will need to be completely recreated.

These problems are reduced with digital mapping. Because features are stored as distinct layers in a computer file, you can modify a map without starting from scratch. Once a feature is modified, ...