Remote Sensing

 As complicated as it sounds, remote sensing is something we all do as a matter of daily life. In essence it is simply the process of sensing something without coming into contact with it. At this very moment you are engaged in remote sensing with your eyes, just by looking at this computer screen. You can distinguish certain colors, which are displayed and can read text symbols. The colors and the text are the information that you are sensing. Being able to distinguish colors and understand the text is the analysis of the information that you are sensing.

In GIS, remote sensing generally refers to the use of aerial or spaceborne sensors. Although not quite the same as human eyes, the sensors on airplanes and earth-observing satellites serve a similar purpose. Unlike your eyes, which can only sense energy in the form of visible light, airborne or spaceborne sensors can sense many different kinds of energy such as infrared, thermal energy, visible light, etc. After the sensors pick up the energy they record it onto a medium and the gathered information gets analyzed and interpreted in much the same way as your brain interprets the information on this computer screen.

Often, remotely sensed image data of the earth's surface is used to recognize natural and man-made features on the ground. The identification of visual elements of the imagery, (pixel signature) by a trained image analyst, can provide valuable information to identify specific features in the image. IGRE analysts use aerial and spaceborne sensed data in projects where it is often too costly or where the area to be studied is too large to collect on-the-ground data. Color infrared image data is often used to identify impervious features and natural features such as wetlands and land cover.