As mentioned in the previous article "Three steps to properly visualize, analyze and measure your environment in 3D" as a surveyor, site manager or environmental project manager, it is important to fully understand the different applications drone photogrammetry in order to see its relevance and derive benefits and advantages.
Here are some examples of widely used photogrammetry applications:
A cloud of dots
It is the 3D representation using points with precise XYZ coordinates (and a color). This application is upstream to generate digital models (DMS) such as digital surface and terrain models (DTM) and triangular meshes. (Application in civil engineering, surveying, environment, etc.)
Numerical models (DTM and DSM)
Allows the 3D representation of the ground and/or its components which serve as a basis for temporal and spatial analyses. (Application in civil engineering, surveying, environment, etc.)
Digital Surface Model (DSM)
Digital terrain model (DTM)
Allows to correctly represent variations of elevation on a ground. Is an application used, among other things, for water level simulations during the installation of a dam or a dyke.
2D modeling of the surface, from several aerial images, making it possible to visualize the site and to carry out precise measurements (Surface, length). One of the recommended applications is the monitoring, before and after, of natural disasters, among other floodplains, landslides, forest fires.
What to remember about the different applications of photogrammetry.
These examples of applications derive from photogrammetry using only images acquired by drones and photogrammetry software (Pix4D and others). This data is very accurate when accompanied by georeferenced ground targets during field capture.