Photogrammetrist / Remote Sensing Analyst
Since the invention of the camera in the mid-1800s,
photography has played a large role in surveying. With the conventional
use of the airplane, an area called photogrammetry became a huge
specialty of surveying.
Photogrammetry is a type of remote sensing, or gathering information about a site without actually coming in contact with it. Photogrammetrists take aerial photos and use them to create detailed maps of large areas in a very short time and for land inaccessible on foot. For example, a photogrammetrist may be hired to track the movement of a pollutant in a large body of water after an environmental accident. In addition to mapping a waterway’s
coastline, photogrammetrists can learn more about topography,
vegetation, and existing structures.
The photogrammetrist in the airplane relies on a surveyor on the ground. The ground-based surveyor will place something known as ground controls at particular locations using precise measurements. The ground controls essentially are giant “X” that the photogrammetrist can see with a detail view of the photo. You may see some of these along roadways or in open areas. Because photogrammetrists know the precise location of the ground control measurements, they can create a map using computerized tools and the photos.
This is an example of the type of computerization
that photogrammetrists use. Their cameras can take
images
at different angles, allowing them to view the images in 3D.
These are referred to as stereoscopic images. Photogrammetrists
use
these images
to detect the contours of the land and the height of objects
on the surface. The
height of trees and mountains can make a difference when builders
design an airport runway, for example.
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