The story of maps starts at least 8000 years ago, when some people first started to draw plans of their town, region, world—or the heavens. At first, they worked from memory or entirely from their imagination. As societies became more ordered and complex, people saw the need for accurate maps. They began to survey the land, taking accurate measurements and plotting features. As explorers reached foreign lands, map-makers (also called cartographers) started to cover larger and larger regions in their maps. Inventions such as the compass, astrolabe and theodolite began to turn cartography into a combination of science, design and technology.

The ancient Mesopotamians were the first to draw maps to scale and to base them on measurements of the land. More accurate maps were important to them, as ownership of land and irrigation systems had become central to their society. Mesopotamian topographic maps marked into clay tablets have been found from around 2350 BC. The Egyptian “Turin Papyrus” map, dating from around 1300 BC, shows the locations of gold and silver mines in the hills between the River Nile and the Red Sea. It may be the world’s first known geological map.

The Romans were concerned with the practical methods of accurately mapping their vast empire, including its roads, the ownership of land and the layout of towns. For the first time, land surveying became a profession in its own right. Roman surveyors established a system of standard measurements, and used geometry and measuring tools such as pegs and ropes, as well as the groma (used to measure straight lines and right angles), to map the land.

Navigation and cartography

From the Middle Ages, the story of cartography is closely linked to the stories of exploration and navigation. The development of the compass, which spread from China to the Islamic World and Europe by the late 12th century, meant that explorers could more accurately plot their course and mark their observations on charts and maps. This led to the development of portolan charts in the 1290s. These detailed maps, which featured scales and compass roses were a breakthrough in navigation at sea. The astrolabe was first used at sea in the late 13th century. It allowed navigators and cartographers to determine their accurate latitude (distance north or south of the equator) by measuring the Sun’s height at noon or the height of a known star.

Surveying

By the early 18th century, surveyors had acquired a range of tools to help them map the land: compass, telescope, “perambulator” (wheel for measuring distance), and quadrant and protractor for measuring and drawing angles.

In 1787, a great step forward was made by the English instrument-maker Jesse Ramsden (1735–1800) when he developed a precise theodolite. A theodolite consists of a telescope that is linked with mechanisms to measure horizontal and vertical angles. The angle to a distant point can be measured by first directing the telescope towards it, then reading the angle given on the theodolite’s scale.

Triangulation

Accurate theodolites were essential for triangulation, a way of determining the location of a distant point using geometry. The technique was developed by the Dutch mathematician Willebrord Snellius (1580–1626). First, the surveyor measures angles from known points at either end of a fixed baseline to a third point. That becomes the third point of a triangle with one known side and two known angles. The surveyor can now calculate the location of the distant point using geometry.

Indigenous mapping

Many peoples around the world represent the space they inhabit in different ways to conventional modern maps. Strict accuracy and scale may be overlooked in favour of other themes. For example, traditional Aboriginal Australian maps combine representations of landforms with a celebration of the meanings of those landforms as part of the Dreamtime; in this way, animals and spirits become part of the map. The Marshall Islanders, who live on a group of islands and atolls in the Pacific Ocean, use stick charts to record ocean currents and wave patterns.