How Maps Work

The Mapmaking Process
A world map by Henricus Hondius, originally published in 1633
A world map by Henricus Hondius, originally published in 1633
Image courtesy Library of Congress

Humans have been making maps for thousands of years. Babylonians etched maps into tablets as early as 2300 B.C. [Source: Britannica]. Some older paintings may also be examples of maps, but archaeologists and anthropologists disagree about whether the artists intended to make a map or paint a picture. Regardless, maps have been around for a long time, and during most of that time, people have drawn and painted them by hand.

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A Map of the world's oceans. Check out more

interactive maps on our Maps channel.

interactive maps on our Maps channel.

You can also see maps of the Indian Ocean and the Arctic Ocean.

You can also see maps of the Indian Ocean and the Arctic Ocean.


­Hand-drawn maps became more accurate as people made new discoveries in math and geography. Accurate estimates of the Earth's diameter helped cartographers depict land masses and oceans in the right proportions. This was especially true after cartographers started mapping both the Eastern and Western hemispheres at the same time. In the 17th and 18th centuries, advances in clock-making made it possible for travelers to determine their longitude accurately, making it easier to get accurate measurements for maps.

Even as advances in technology made it easier to get accurate map data, creating a good map still required the skill of an artist. A mapmaker had to be able to draw or paint all of the map's features so that they were accurate, legible and attractive. The same is true today. Computers and geographic information systems (GIS) have automated many mapmaking tasks, but the best maps still come from skilled cartographers.

When making a map, a cartographer has to consider several factors, including:

  • The purpose of the map: This will determine which data the cartographer needs to gather. It will also affect what the map looks like. For example, a large-scale map that will hang on a wall will have significantly more detail than a small-scale map that will be part of a desk atlas.
  • The intended audience: "One of the most important considerations that a cartographer has to make," says Ian Turner, "is the audience for which it is intended…a map for a young elementary-school student is generally much simpler, has less type, fewer colors [and] is much easier to read than a map for an older student or an adult."

In the next section we'll take a look the requirements for maps that are meant to be viewed online.

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