Definition of Photogrammetry

Photogrammetry is science of obtaining information about specified physical objects through the process of recording, measuring, and interpreting photographic images.

Who Uses of Photogrammetry?

Everyone uses photogrammetry! Reading this information is a simple use of photogrammetry because you are recording this information with your eyes. Driving your car and determining when to stop is another application of photogrammetry because you are measuring distances with your eyes. Everyday people are recording, measuring and analyzing data if they realize it or not!

Surveyors can record and accurately measure physical objects this same way with the help of photogrammetric technology such as expensive cameras, laser scanners (LiDAR) , and GPS (Global Possitioning Systems) . They can use these technologies practically anywhere, on the ground (terrestrially), in the water (hydrographically), or in the air (aerially). Aerial photogrammetry is the most popular method because most clients order large scale maps of land.

History of Photogrammetry

The science of creating images and photographs dates back to the 1400’s believe it or not! Leonardo di Vinci is one of the earlier explorers of the science. Since then other scientists continued this work on projective geometry mathematically. In 1525 Albrecht Duerer used laws of perspective and created an instrument that could be used to create a true perspective drawing. From this same idea scientists began developing mathematical principles of a perspective image using "space resection" (determining the coordinates of a point from two or more images) to find a point in space from which a picture is made. The actual relationship between projective geometry and photogrammetry was first developed by R. Strums and Guido Haick in Germany in 1883. Since then the science went through four development cycles.

· Plane table photogrammetry, from 1850 to 1900

· Analog photogrammetry, from about 1900 to 1960

· Analytical photogrammetry, from about 1960 to present

· Digital photogrammetry, is just now beginning to be a presence in the photogrammetric industry

Now laser scanners and digital images are making a huge impact on the profession of photogrammetry.

Why Do Suveyors Use Photogrammetry?

The most common use of photogrammetry is to create maps from images of physical features. These physical features include land, waterways, buildings, pipelines, or even roadways. Basically, anything that a person sees can be remodeled or mapped by using images. Surveyors have the ability to measure any specified object with very high precision and accuracy with the tools provided to them.