How Maps Work

A map of the world’s time zones.
It’s easy to think of maps as sets of visual directions.
Whether you’re trying to get to the top of Mount Everest or
to a friend’s new home, a map can help you find your way.
But maps can do more than help you figure out where you
are and where you’re going. They are representations of
information that can describe nearly anything about the
world.
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If you wanted to get an idea of which dog breeds are most
popular in different regions, you might spend days looking
at lists and charts. Or, you could look at a map and get an
instant grasp of the same information. Learning about the
physical features, imports, exports and population densities
of different countries would take ages if you relied on
written descriptions in a book. But with a map, all of the
numbers, patterns and correlations are right in front of you.
As Ian Turner, senior cartographer at GeoNova, puts it, “a
map is a type of language. It’s a graphic language. It
presents information in hopefully a way that is very easy to
understand.”
It’s the job of a mapmaker, or cartographer, to put all of
this information into a format that people can understand
and learn from. Exactly what a person can learn depends
on the type of map. Most maps start with an outline of a
location, like a piece of land or a body of water. Then, they
provide information about the location’s attributes.
Different maps incorporate different attributes. For
example:
Physical maps illustrate landforms like
mountains, deserts and lakes. With a physical
map, you can get a basic sense of what all or
part of the planet looks like and what its
physical features are. Physical maps usually
show differences in elevation through
hypsometric tints, or variations in color.
Topographic maps, on the other hand, illustrate
the land’s shape and elevation using contour
lines.
Political maps display cultural information
about countries, their borders and their major
cities. Most political maps also include some
physical features, like oceans, rivers and large
lakes. You can check out political maps of the
world at our interactive atlas.
Thematic maps add information on a specific
theme, or subject. Examples of common themes
are population density, land use, natural
resources, gross domestic product (GDP) and
climate. Thematic maps can also show
extremely specialized information, such as the
availability of Internet access in different parts
of the world.
This combination of locations and attributes makes it
possible to put lots of information into a very small space.
A single map can show you all of the countries on a
continent, their borders, their approximate populations and
their primary imports and exports. People can also use
specialized thematic maps to analyze trends and patterns
in all kinds of data. A map showing communication costs in
different parts of the world, for example, could help a
nonprofit organization decide where to build a low-cost
wireless network. As Turner explains, “Maps geography
more than about capitals and countries – it’s really about
how economics and climate and natural features, how all
the different variables that make up a society relate to one
another.”
Common conventions help cartographers present all this
information in a way that makes sense. We’ll look at them
in more detail in the next section.