Topographic maps are one of the most useful tools for studying the Earth’s surface. They are also invaluable for planning architecture or when accounting for the contours of land during urban planning.
Topography has helped shape so many of the things we know and love today. It has helped create topographic Google Maps, beautiful large-scale, architecture and even our best roads and railroads.
But what exactly is topography? Here’s everything you need to know about topography and topographic maps.
What Is Topography?
Topography is the study of the Earth’s surface and all its lumps and bumps. It looks at the contours of the land, the vegetation covering the surface, and any man-made features. Topography can be an ongoing study, as Earth scientists will study changes in the Earth’s surface. For example, they may monitor the movement of mountains or rivers.
As well as referring to the study of the Earth’s surface, topography can also be used when studying the surfaces of other planets. Scientists use it to map the surface contours of the moon, asteroids, meteors and neighboring planets.
What Are Topographic Maps?
Topographic maps are also known as topo maps or contour maps and record and display the contours of the Earth. These 2D maps depict the three-dimensional land surface by using contour lines. Contour lines represent the land’s elevation above sea level. The closer together contour lines are, the steeper the rise and fall of the land.
Sometimes topographic maps use colors to signify specific features. For example, brown represents the contours of the land; black shows man-made features such as buildings or roads, and blue shows rivers. Sometimes maps will also have purple features. Purple represents features added after the map’s creation.
A Brief History of Topographic Maps
One of the first uses of topographic maps was in the eighteenth century when the British military carried out detailed surveys of land.
The United States military followed suit and also used topographic maps for tactical strategies — there was even a “Topographical Bureau of the Army” during the war of 1912. Pioneers in America also used and created topographic maps as they began to explore more of the country and expand their geographical knowledge of Western America.
Topographical engineers used topography to plan the routes for the Pacific Railroad, a railroad that today spans over 32,000 route miles.
Topography has come a long way since the eighteenth and nineteenth centuries. Now we can create more detailed contour maps that take into account not only the Earth’s surface but also man-made structures — and the surfaces of other planets.
What Are Topographic Maps Used For?
Nowadays, topographic maps have a number of uses. For example, they can identify mining opportunities, potential pond sites, and hiking routes.
The most common use, though, is in urban planning. Large-scale building projects and highway planning agencies need to take into account the contours of the land to create structurally-sound buildings and efficient road routes.
How Are Topographic Maps Created?
Topographic maps are much more accurate than they used to be because of the way we create them. The maps are made using point cloud data — a collection of points or 3D coordinates representing a 3D object or landscape.
The first step towards creating a topo map is to collect the point cloud data, usually some kind of LiDAR system like a Mobile Mapper using either Airborne LiDAR or photogrammetry. LiDAR collects measurements using laser light pulses, whereas photogrammetry involves photographing land from above and calculating measurements from the photos. Surveyors may use one of these techniques or combine the two to gather point cloud data.
After registration, the point cloud data is then processed using point cloud processing software. The software can transform the data into a topographic map.
TopoDOT point cloud processing software can help you transform your point cloud data into a topographic or 3D digital map. You can automatically extract topographical features from survey data and save time and money as a result.