How is Geographic Data Gathered for Maps?
There are a variety of ways to collect geographic data for maps. The most common methods are aerial surveys, satellite imagery, and ground surveys.
Aerial surveys use airplanes or helicopters to photograph the earth’s surface from above. This method is used to collect data on large areas, such as entire states or countries.
A pilot and a camera operator work together to take photos from the aircraft, and an onboard GPS records the exact position for each image. Once all of the images are taken, they are processed through photogrammetry software—a type of computer program that converts images into usable geographic data.
Satellite imagery involves taking photographs of the earth’s surface from a satellite. This method is used to collect data on smaller areas, such as cities or neighborhoods. Satellite imagery can be used to capture features on the earth’s surface that are difficult to see from the ground, such as buildings, forests, and waterways.
Ground surveys involve collecting geographic data directly from the earth’s surface. This method is used to collect data on small or specific areas, such as a city block or a single tree.
Ground surveyors use tools such as GPS units and digital levels to pinpoint the exact location of each feature they want to record. They often walk around with measuring wheels to find out how big an area is. They also take note of physical features, such as the direction of a river or the layout of a neighborhood.
Once the data is collected, it is processed and compiled into a map. Geographic data can be used to create a variety of different maps, including topographic maps, street maps, and climate maps.
Maps are an important tool for understanding and navigating the world around us. By gathering geographic data in a variety of ways, we can create maps that are accurate and tailored to our needs.