Data acquisitions in Geomatics field

Acquiring information is the essential foundation that brings content to Geomatics. The acquisition includes all the methods and techniques for capturing and collecting data relating to the natural and built environment. Numerous techniques and sensors make it possible to acquire thematic and geometric information on the territory.

 

Data acquisitions in Geomatics field

Geodesy

Any acquisition method relies on a reference system associated with a coordinate system. When we consider the Earth as a reference object, the definition of a coordinate system attached to the globe is not trivial; it is one of the goals of geodesy. This science consists in studying the geometry of the Earth with its shape and dimension in a physical reality (gravity field) and with its own dynamics (plate tectonics).

 Remote sensing

Remote sensing is the process of capturing and describing objects or a portion of territory remotely using image sensors. Each element on the surface of the Earth reflects, absorbs and transmits a different radiation according to its structure as well as its chemical and chromatic qualities. Radiation reaching a sensor from an object on the surface of the Earth is called electromagnetic radiance.

Photogrammetry

Photogrammetry is a technique for studying and precisely defining the shapes, nature, dimensions and position in the space of an object, from a stereoscopic pair of photographs of it.
Photogrammetry includes a set of operations such as shooting with calibrated cameras and reproducing pairs of images with 3D digitization methods based on the principle of stereoscopic vision.

The scanned laser

The laser scanner is a technique that allows the fast and accurate acquisition of surfaces as sets of points characterizing them and called point clouds. These operations are carried out from aerial or terrestrial platforms. The laser can be used from a fixed point or in motion depending on the project and the nature of the terrain to be modeled. Point clouds are processed and filtered to provide geometric modeling of major scanned objects or surface models of vegetation and terrain

Topography

The topography includes all the field and office operations allowing the seizure of natural or built objects and the implementation work which consists in placing landmarks on the ground according to a project (ex the hold of a building). Topographic methods are those commonly used by surveyors with instruments such as Total stations