What are the three types of photogrammetry?

Photogrammetry can be classified into three main types based on the distance between the camera and the object being photographed. These types are distinguished by the scale of the photogrammetric process:

1. Close-Range Photogrammetry:

   • Overview: Close-range photogrammetry, also known as terrestrial photogrammetry, involves capturing images of objects or scenes from a relatively short distance. This can include capturing images on the ground or from a stationary platform.
   • Applications: It is commonly used for applications such as architectural documentation, industrial measurement, forensic analysis, and cultural heritage preservation.
   • Characteristics: Close-range photogrammetry allows for high precision and detailed modeling of individual objects or structures.

2. Aerial Photogrammetry:

   • Overview: Aerial photogrammetry involves capturing images of the Earth's surface from an elevated position, typically using aircraft, drones, or other aerial platforms.
   • Applications: It is widely used in cartography, topographic mapping, environmental monitoring, and large-scale surveying.
   • Characteristics: Aerial photogrammetry provides a comprehensive view of landscapes and large areas, allowing for detailed mapping and analysis.

3. Satellite Photogrammetry:

   • Overview: Satellite photogrammetry involves capturing images of the Earth's surface from satellites orbiting in space.
   • Applications: It is used for large-scale mapping, environmental monitoring, and global-scale geospatial analysis.
   • Characteristics: Satellite photogrammetry allows for the acquisition of imagery over vast areas, making it suitable for applications that require a global perspective.

These three types of photogrammetry share common principles, such as the triangulation of image points to derive 3D coordinates. However, they differ in terms of the scale of the data acquisition process and the distance between the camera and the object or area being studied. The choice of the photogrammetric method depends on the specific requirements of the project, including the scale, resolution, and accessibility of the area of interest.