What are the two types of photogrammetry?

Photogrammetry can be broadly classified into two main types based on the type of imagery used and the nature of the data acquisition process:

1. Aerial Photogrammetry:

   • Overview: Aerial photogrammetry involves capturing images of the Earth's surface from an elevated position, typically using aircraft or drones.
   • Applications: It is widely used in cartography, topographic mapping, environmental monitoring, urban planning, and other applications where large-scale coverage and high-resolution imagery are required.
   • Advantages: Aerial photogrammetry provides a comprehensive view of landscapes and large areas, enabling detailed mapping and analysis.

2. Terrestrial (Close-Range) Photogrammetry:

   • Overview: Terrestrial photogrammetry involves capturing images of objects or scenes from a relatively short distance, often on the ground.
   • Applications: It is employed in fields such as architecture, archaeology, forensics, industrial measurement, and cultural heritage documentation. It is suitable for smaller-scale objects or localized areas.
   • Advantages: Terrestrial photogrammetry allows for high precision and detailed modeling of individual objects or structures, capturing fine details with close-range imagery.

These two types of photogrammetry share the fundamental principles of triangulation and image matching to derive 3D information from 2D images. However, the choice between aerial and terrestrial photogrammetry depends on the specific requirements of the project, such as scale, resolution, and accessibility.

In both cases, the photogrammetric process involves capturing overlapping images, identifying corresponding points in these images, and using triangulation techniques to calculate the 3D coordinates of points in the scene. The resulting data can be used to create accurate 3D models, maps, or other spatial representations.