Stereoscope

Pocket Stereo Viewers

Field observers often use pocket stereoscopes to map the perimeter of the fire, and to locate hotspots, islands of unburned fuel, and water resources. Field observers use soft lead color pencils to record their observations directly on aerial photographs. They may rely upon a pocket stereoscope to confirm their identification of areas of concern before recording their observations on the aerial photograph.

Stereoscopes vary in size from desktop to pocket models. On a large wildland fire, where an incident command base has been established, the desktop stereoscope may be used by personnel in the Operations section to plan future firelines or by the Planning section to accurately create a map for firefighters.

Stereoscopes are useful field tools, but they are quickly being replaced by global positioning systems, which are able to create and print maps more quickly and accurately.

When a wildland fire occurs aerial photographs are used to identify structures that may be damaged by a fire, and to locate communication facilities, access roads, and special resource areas. Aerial photographs are taken in lines with one photograph overlapping the next as the aircraft progresses across the landscape. Once the aircraft finishes a line, it is turned, and a photograph is taken of the next line adjacent to and overlapping the previous line. A map with numbered flight lines and aerial photograph locations, numbered along those flightlines, is also created so photographs can be easily found for any area of interest. Stereoscopes are used to get a 3-dimensional view of the overlapped parts of aerial photographs.