Topographic map facts for kids
A topographic map is a special kind of map. It shows the shape of the land, including hills, valleys, and flat areas. These maps use contour lines to show how high or low the land is. Imagine walking along a contour line – you would stay at the same height! Topographic maps are usually very detailed. They are made using careful measurements of the land, called surveying.
Topographic maps are useful for many things. They show natural features like mountains, rivers, and forests. They also show things people have built, like roads, railway lines, and towns. These maps are updated regularly to keep them accurate. Even town maps are often based on this detailed information.
How Topographic Maps Started
Topographic maps come from something called topographical surveys. These surveys were very detailed. They showed all the different heights and shapes of the land. This was different from older maps that mainly showed property lines.
The first big series of topographic maps for a whole country was finished in France in 1789. It was called the Carte géométrique de la France. Another famous project was the Great Trigonometric Survey of India. It started in 1802. This survey was huge and helped measure the heights of the Himalayas. They could even figure out mountain heights from over 100 miles away!
At first, armies used topographic maps a lot. They helped plan battles and build defenses. This is why knowing the land's height was so important. For example, the United Kingdom's Ordnance Survey started this way.
Over time, topographic maps became important for countries. They helped plan new roads, buildings, and how to use natural resources. In the United States, the job of making these maps went to the United States Geological Survey in 1879.
In 1913, a project called the International Map of the World began. The goal was to map all the important land areas on Earth. They planned to use a scale of 1:1 million. Even though the project didn't finish completely, it created a useful system for organizing maps.
Maps in the Digital Age
By the 1980s, computers started changing how maps were made. Instead of printing many paper maps, information was stored in computer databases. People could then use computers to create their own maps. They could choose what to show and at what scale.
For example, the US government created the TIGER system. It stored information about borders, roads, railways, and rivers. This helped with the United States Census. Also, Digital elevation models (DEM) were created. These are digital maps that show land heights. They were made from old maps, aerial photos, and satellite data. Since these were government projects, the data was free for everyone to use.
These digital maps made geographic information systems (GIS) much better. They also made the Global Positioning System (GPS) more useful. GPS tells you your exact location. But with digital maps, you could see your location on a map.
At first, these tools were mainly for experts. But by the mid-1990s, they became easier to use. Online maps, GPS in mobile phones, and car navigation systems appeared. Today, many people use digital maps every day. This means that traditional paper topographic maps are not as common as they once were.
Images for kids
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A section of a topographic map of the Nablus area. The contour lines are 100 meters apart. Different heights are shown with colors.
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A Curvimeter is a tool used to measure the length of a curved line on a map.
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A topographic map of the Mount Marcy area in New York from 1892.
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The same area about a century later (1979). This map is more detailed and uses metric measurements.
See also
In Spanish: Mapa topográfico para niños
