Photogrammetry is the science and technique that blends photography and geometry. The principle is straightforward, yet it has a significant impact on contemporary architectural establishments.

What is the procedure of photogrammetry, you can check here–

We all know that photography generates 2D illustrations. The photogrammetry system produces 3D estimations of the object and surface from the 2D image/photograph.

If you read our previous blogs on photogrammetry, then you will know that Aerial and Terrestrial are two major varieties of photogrammetry.

Let’s understand each one by one-

Aerial photogrammetry

A machine, especially an aircraft (purposefully designed plane) or a drone, i.e. Unmanned Aerial Vehicle (UAV) has the cameras attached. Therefore, it can capture photos from the higher surface. The larger the number of images, the higher is the accuracy of the statistics. It further helps in comparison of the quality.

The planes fly over the planned area with particular landmarks which they have to capture. The speed of the aircraft regulates the camera’s catching speed. Also, they know the height of the plane from the land surface. The photographed surface area’s base contour/boundary is drawn using Stereo Plotters.

Terrestrial photogrammetry

The word Terrestrial means relating to Earth. Therefore it explains that why the camera is in the stationary position in this kind of photogrammetry. The camera’s position is elevated, and the tilt angle, the focal length of the lens is adjusted.

Read More on Why Aerial Photogrammetry Differs from the Terrestrial One.

The main difference is between the working and methodologies, even though both are the branches of the photogrammetry.

Therefore, the outputs generated are very varied from each other.

Apprehend the following points to notice the distinction-

• The technical requirements of the Aerial photogrammetry are very high-end; the specially designed planes or drones are just the initials.
• Although there is a much lesser investment in Terrestrial photogrammetry, there is the requirement of high technical skills for operating the tools.
• To map a large surface area of the land, we can use Aerial photogrammetry. But the knowledge of longitudes and latitudes with their calculations are essential in photogrammetry operation.
• When there is a need for designers and planners to manage and plan bridges, transportation network, pipeline networks, etc. then Terrestrial photogrammetry is preferred. The adjustments of the camera’s axis as per the surface area matter a lot.
• The environmental projects which trace the changes of glaciers, volcanoes, earthquakes, etc., use terrestrial photogrammetry methods.
• The fixed location of the camera creates such kind of data sets to work upon further.
• There are various benefits of aerial photogrammetry in the security field as well. Archaeology also gets numerous advantages through aerial photogrammetry as you can see a big chunk of the area at once.
• Terrestrial photogrammetry is preferable for movement-related and comparatively smaller land masses, unlike the aerial one.
• The arena where both the fields play an active role is Urban Planning! That’s obvious as with the help of aerial photogrammetry, designers and planners generate an accurate perspective plan of the site or location. An aerial view gives a bright idea of all around the neighborhood, and so it helps in further assessment.
• Terrestrial photogrammetry, unlike aerial, creates visuals showing interrelation between civil constructions, safety issues, disaster management and various other problems. Thus, it helps in knowing the creation, prevention, and demolition of any civilization.

Final Derivation

Thus, it’s evident that by using both sorts of photogrammetry, we can generate most efficient and disaster-prone constructions/infrastructures.

So these were the fundamental differences between aerial and terrestrial photogrammetry. Have you had a clear insight?

Do write your views in the comments.