Photogrammetry

Definition

Photogrammetry is the science and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring, and interpreting photographic images. It involves using images captured by cameras, typically mounted on aircraft, drones, or satellites, to gather and analyze spatial information. This technique allows for the extraction of three-dimensional measurements from two-dimensional photographic data, enabling the mapping and modeling of the Earth's surface and other physical features.

What is Photogrammetry?

Photogrammetry is a method used within the field of geographic information systems (GIS) to create maps, 3D models, and measurements of real-world environments. By utilizing multiple overlapping photographs taken from different angles, photogrammetry can reconstruct the geometry of a scene or object in three dimensions. Through this process, analysts can derive detailed and accurate spatial data, such as elevations, distances, and volumes, which are essential for a variety of applications including topographic mapping, architecture, engineering, and archaeology.

Photogrammetry is divided into two primary types: aerial photogrammetry and terrestrial photogrammetry. Aerial photogrammetry involves capturing images of the Earth’s surface from above, commonly using drones or aircraft, to produce large-scale maps and models. Terrestrial photogrammetry, on the other hand, involves using images taken from handheld or ground-based cameras for purposes like documenting building facades or archaeological sites.

FAQs

How does photogrammetry work?

Photogrammetry works by capturing multiple images of an object or area from different angles. Specialized software then processes these images to identify common points and generate a 3D representation or map by calculating the spatial relationships between these points.

What are the applications of photogrammetry?

Photogrammetry is used across various fields including topographic mapping, architecture, civil engineering, archaeology, and forestry. It is valuable for creating digital elevation models, measuring physical structures, and monitoring environmental changes.

What is the difference between photogrammetry and LiDAR?

Photogrammetry uses photographic images to measure and map terrain while LiDAR uses laser pulses to calculate distances and create detailed 3D models. Both have their own advantages and are chosen based on the specific requirements of a project.

What are the advantages of using photogrammetry?

Advantages of photogrammetry include cost-effectiveness, the ability to capture large areas quickly, high-resolution image data, and the production of visually appealing 3D models and maps that are useful for various analyses and applications.