Q: How are maps made?
A: This is a complicated question and we can't
answer it completely here. We'll just point out some highlights.
People who create maps are called
cartographers. The first thing a cartographer does is to decide what to
show in the map. A photo shows everything in front of the camera. A map
shows only what we want it to show. So the cartographer must first
spend some time thinking about that.
The next task is to find sources of information.
Where are the
coast lines? Where do the rivers run? The roads? In the past we had
libraries of "base
maps" containing these details, and we'd trace those lines on
to the new map, then add the details we wanted to show. Today
computers store our base maps; we have to decide on the scale and
the amount of detail.
Of course this raises the question: how was the
base map created? That's a long story, and we'll cover it some other
There are many kinds of maps. Some are for
tourists and visitors; they show roads and important buildings. Some
are for scientists; they may show temperature and rainfall. Today,
using computers, we can make maps much more easily, so we use them to
show just about anything: houses for sale, the amount of traffic, crime
statistics, the route to Grandma's house. These are called thematic
maps because they focus on a theme. The biggest challenge in making
thematic maps is
to get the data right, and to convey the right message to the viewer.
This takes a lot of training.
Drawing the map used to be very laborious.
Cartographers would spend hours with pens and etching knives, creating
drawings in mylar (plastic) layers, one for each color, and stenciling
the text or sticking it on. Today this is done entirely by computer.
Up to the 1980s, computers used pens and ink too; they would dart
around the paper
drawing the same things humans did, only much faster. Today laser
printers do much of this. They draw the lines, print text, and
color the areas, and so maps can be created quite fast. Some of
the most useful maps are created only on computer screens and are never
printed. It still takes cartographers to decide the
color and thickness of lines, what to place in the center and on the
As we push into the future, we're starting to deal
with maps that change in front of our eyes. For example, maps showing
population growth. The animated weather maps on TV. The GPS navigation
screens in cars. These maps can be very difficult to design, because
the cartographer never quite knows what they'll have to show; and they
have to be
re-drawn, sometimes several times a second. So modern cartographers
have to think carefully about what map viewers need, how to place items
on the map with just the right amount of detail, and how to put the
right label on things in such a way that they don't run into each
other. Cartographers now have to
know a fair bit about computers and how to organize the information so
that the computers can get the job done fast.