Geodetic markers are physical objects placed on the Earth's surface to help measure and define its shape, size, and gravitational field. These markers are crucial for mapping and surveying, providing reference points for geographers, engineers, and scientists. They can be made of various materials, such as metal or concrete, and are often found in remote or elevated locations. These markers are part of a larger system known as geodetic networks, which connects multiple markers to create a comprehensive framework for spatial data. They play a vital role in applications like GPS technology, land surveying, and cartography, ensuring accurate positioning and navigation.