Route surveying and design

60 TABLE XX.—NATURAL 60 VERSINES AASHTO aerial alignment design Approx approximate Arc Definition balance line BASE BASE BASE base line calculated central angle chord definition circular arc combining spiral compound curve computed construction contour coordinates Corr correction COS1NE FOR VERS1NE COSINES cross sections curvature defl deflection angles degree of curve design speed digits earthwork elevation engineer equal equation example field formula full stations grade gradient ground highway horizontal inverse program layout length measured method middle ordinates offset offset curve osculating circle parabola pavement Pennsylvania Turnpike Photogrammetry planimetric radians radius railroad reconnaissance result reverse curve right-of-way route surveying S1NE FOR COS1NE scale setup sight distance simple curve simple spiral stereoplotter subchords superelevation TABLE XX.—NATURAL SINES tangent tape terrain topography transit traverse triangle U2 U3 UU UU U5 values vers VERS1NE EXSEC vertical curves