by Juan Chow, Maureen Kennedy, Rebecca Tedford and Carrie Walker.

The SOKKIA Set 6F theodolite projects a laser beam to a prism target and returns a 3-D coordinate set in the form of N, E, and Z. Juan and Rebecca

The theodolite requires a coordinate set as its starting position. We choose due north as our Yo coordinate, due east as our Xo coordinate, and Zo to be the vertical direction; Xo, Yo, and Zo are all zeros at the theodolite measuring station. a Fig. 1. a = Azimuth angle. Angle on the horizontal plane that diverges from Xo (in our case, North). from the vertical above the theodolite to the line that defines the slope distance S.

 
 

Ih is the height of the theodolite. Th is the height of the prism target; because these two heights are not equal and are not on the surface of the land, they must be taken into account when calculating Z. b Fig. 2. b = Zenith angle. Angle measured from above the theodolite down to the line that defines the slope distance S. (See Fig. 3.)

S Z Fig. 3. S = Slope distance. The direct distance from the theodolite to the prism target. Z = Height difference between Zo and the height of the land at the prism target. S = N / cosa sinb = E / sina sinb Z = Zo + Ih + S (cosb) ñ Th (for our purposes, Zo = 0)

 
 

a asadsda Fig. 4. Plan view of the relationship among N, E, and a (azimuth angle). N = Distance from the theodolite to a point along the Yo axis that is perpendicular to the target. = Yo + ( S sinb cosa)  E = Distance from the theodolite to a point along the Xo axis that is perpendicular to the target = Xo + ( S sinb sina)

Go to: * Contour Maps  * 3D Views  * Composite 3D View  -> Back  Maureen and Carrie

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

.