Remote Sensing & Photogrammetry

Google Earth is commonplace on many home computers these days, and weather maps are seen on the television in almost every household. These are just a few commonplace examples of remote sensing and photogrammetry.

The history of modern remote sensing and photogrammetry began with the invention of the camera more than 150 years ago, and it was used for early topographic surveys and close range applications, and for aerial surveys after the invention of the airplane in the first decade of the 20th century. The term photogrammetry emerged first in Germany in 1867. It is generally described today as the science and art of determining the geometric properties of objects from images recorded from aircraft, satellites or at close range. Photogrammetry is used extensively for such applications as topographic mapping, measurements of terrain form, and close range measurements of objects, such as for engineering, architecture, archaeology, medicine, law, machine vision. Modern photogrammetry also includes airborne and terrestrial based lidar (light detection and ranging) based on the principle of laser scanning.

The term “remote sensing” is believed to have been used first in the United States in the 1950s, and is now commonly used to describe the science and art of identifying, observing and measuring objects or phenomena without coming into direct contact with them. Described very generally, this process involves the detection and measurement of radiation of different wavelengths reflected or emitted from distant objects or materials, by which they may be identified and categorized by class/type, substance and spatial distribution. There is no special significance, however, in the degree of "remoteness" of the sensor from the object surveyed, and any form of non-contact observation can be regarded as remote sensing.

Satellite remote sensing can be traced to the early days of the Russian and American space programs. With the emergence of the space programs in the 1960s, satellite imagery was used for meteorological purposes. However, space remote sensing really began in a commercial sense with the launch of the ERTS satellite, later named Landsat-1 in 1972. It has developed a great deal since the early days of Landsat, with hundreds of satellites now in space, acquiring data in a broad range of wavelengths and spatial resolutions.

Aerial Photography and Satellite Imagery, as well as in traditional application areas, are used today in an ever increasing number of industries, including emergency management mapping floods and fires, environmental groups measuring change in vegetation over time, mining companies keeping an eye out for new prospects and monitoring exisiting facilities, … the list goes on.