We explain what topography is, its history, branches and importance. Also, what is topographic measurement and geodesy.
What is topography?
The topography It is a geometric science dedicated to the graphic representation of the Earth's surface. It is the discipline that studies the principles and procedures that allow us to illustrate the shapes, details and elements of the Earth, both natural and those created by humans.
Said representation is always made with respect to a limited area of land, applying an imaginary plane and a set of three-dimensional coordinates (x, and, z). The result is a topographic map, which indicates the relief of the studied area.
So, Topographic maps show the elevation of the terrain through systems of lines that connect specific points with a reference plane, which is usually sea level.
Topographic studies are very important for other disciplines, such as surveying, architecture, archaeology, geography, caving, cartography, mining, oceanography and a huge compendium of engineering.
It is especially useful when building or carrying out civil engineering works, since topography basically deals with faithfully describing the immobile physical reality of a given place, be it a city, a field or a valley between mountains.
History of topography
Although there is no certain inventor of topography, It is estimated that the ancient Egyptians and Greeks of the classical era practiced it with relish, being as they were important builders. There is evidence of the work carried out by the Pharaoh's surveyors, marking on each tilled land the portion that was intended for his majesty.
At the same time, the first to make geographical maps themselves were the Greeks Thales of Miletus and Anaximander, so they could serve as initiators of the practice of graphical representation of the terrain.
The truth is that the topography had its formal entry as a science at the hands of private property since it is an important discipline for the expansion work of the States and for the construction sector of public and private works. In this, it is a fairly modern science.
Types of topographic measurement
Topography work is always done on the ground, that is, always in the field of study itself. They are distinguished, however, by their methodology when making a measurement:
- Direct measurement It acquires its data directly, that is, by comparing the real distance with the unit of measurement that describes it, such as using a tape measure, for example.
- Indirect measurement One in which measurements are obtained through the application of a mathematical formula and other forms of abstract reasoning.
Branches of topography
Broadly speaking, topography comprises three branches or subdivisions:
- Surveying Considered in many ways an autonomous discipline, it is dedicated to the measurement of distances of the Earth's surfaces, that is, measurement of areas and definition of legal boundaries.
- Classic topography It uses an abstract system of references or spherical coordinates, which can then be translated into a Cartesian axis to obtain, through calculations, the proportions of a physical space. It is divided into two, in turn:
- Planimetry. Measuring flat surfaces.
- Altimetry. Measuring heights.
- Geodesy It is responsible for graphically representing the surface of the Earth, understood as a macro set of surfaces, that is, based on large sectorizations, which often implies sacrificing the imaginary topographic plane.
Importance of topography
Topography is fundamental in the measurement and representation of the world, especially for those who require a detailed description of certain sectors of it, such as navigators, construction engineers, architects, telecommunications engineers, and a huge etcetera.
For that reason Surveyors are typically involved in the initial stages of virtually all construction projects. Topographic surveys are key in the planning and adaptation of abstract ideas to the tangible physical space where they will be realized.
Topography and Geodesy
The fundamental difference between topography and geodesy is due to the fact that geodesy has a macro approach. It globally evaluates the Earth's surface, serving as a basis for other geosciences and geographic information systems.
Initially it was thought of as a branch of topography, but today it is even thought that the hierarchy between these disciplines could be the other way around, and topography would be a kind of practical or inferior geodesy.
Continue with: Geophysics
References
- “Topography” on Wikipedia.
- “What is topography? What is the origin and where are we going?” (video) at Alfa Geomatics.
- “What is topography?” in Topoequipos.
- “What is topography?” VERY Interesting.
- “Topography” in The Encyclopaedia Britannica.
