Photogrammetry is the science of making measurements and maps using photographs.
For example, a technician aboard an aircraft takes a series of overlapping
photographs of an area to be mapped. Adjacent images are placed in an instrument
called a stereo-plotter and calibrated using data obtained by surveyors in
The resulting 3D image allows a photogrammetric technician to draw contour
lines (lines of equal elevation) and enlarge the area of interest. The final
map shows the features and elevations of the surface. New technologies allow
contour information to be overlaid on ortho photography.
Technology is influencing photogrammetrists and cartographers. They have
evolved into a new type of mapping scientist known as a geographic information
system (GIS) specialist.
"GIS [specialists] drive a lot of projects, and we are a little down on
the food chain," says Thomas Asbeck, who works with a photo science company
in Bangor, Maine. "But generally, GIS is a boon to photogrammetry because
GIS systems have to have some kind of base maps, and that is what we do."
"Everything is becoming more automated," says Ken Sherman, a geomatics
instructor. "There is a shift away from the mechanical instruments to a computer-driven