Topographic maps are digital, graphic maps that portray the horizontal position of planimetric
features using lines and symbols. Contours are derived from a Digital Terrain Model (DTM) to
represent the elevation of the ground. Ground control is set for this product. Aerotriangulation
is performed to determine the position and orientation of the camera for each exposure so planimetric
features are shown in their true relative coordinate position. A DTM is collected to represent the surface
of the earth.
Typical map scales are
1 inch = 100 feet and
1 inch = 200 feet.
Topographic maps are used for preliminary design of transportation projects.
Topographic maps, including contours, with associated X, Y coordinate system, and the DTM
are delivered to the customer.