The science of surveying investigates different ways to fully represent the Earth's surface Because of the natural features it contains, such as mountains, plateaus, valleys, rivers, seas, and forests, and industrial or civil features, such as various engineering facilities, such as buildings, roads, and airports. This representation is done by projecting the part of the Earth’s surface that is being studied onto a horizontal plane with az specific drawing scale that matches the desired purpose. The horizontal projection that we obtain is called the “cadastral map.” On which the height or fall of natural or artificial features can also be shown in relation to a specific horizontal comparison surface. In most cases, the average surface of the sea is used as a reference for comparing heights.