It is a technique that aims to study and define precisely the shape, dimensions and / or position in the space of an object, through the data obtained from one or several photographs.
One of the main applications of photogrammetry is topography as it allows to measure coordinates in three dimensions and also results in the complex representation of an object in an easy-to-use document. To this is added that the instantaneous nature of the record, with the consequent agility to process the information against the classical topography.
There are many advantages of photogrammetry compared to classical topography.
- Agility and speed in data collection
- Access to hard-to-reach land
- Use of drones
- Detailed land registration continuously
Types of photogrammetry
- Terrestrial photogrammetry. There is a fixed point of view and therefore its coordinates and focus orientation are known.
- Aerial photogrammetry. The point of view is mobile and gives a wide range of feedback, but neither the position of the camera nor its orientation at the time of shooting is known, although the technology and the digitalization of the processes allows solving these problems.
The method used to obtain these images is as follows:
- Photography of objects. To do this, you must first perform a flight planning (aerial photogrammetry) and survey of ground control points through terrestrial photogrammetry.
- Image processing. Once the photographs are obtained, they must be processed in specialized analytical software to generate standard documents in the industry such as: color point clouds (.las, .laz, .ply, .xyz), classified point cloud (.las, .laz), orthomosaic (.tif, .kml), digital surface model DSM (.tif, .xyz, .las, .laz), digital DTM terrain model or digital DEM elevation model (.tif). contour lines (.shp, .dxf, .pdf) .. among others.
Its applications are numerous:
- Digital mapping
- Planning and planning of the territory
- Heritage conservation
- Structure control
- Video game
- Movie theater