Route Surveying and Design

60 TABLE XX.-NATURAL 60 VERSINES aerial Approx approximate Arc Definition balance line BASE BASE BASE base line calculated Cb Cp central angle chord definition circular arc combining spiral compound curve computed construction contour coordinates Corr correction COSINE VERSINE EXSEC cross sections curvature D₁ DEFL deflection angles degree of curve design speed digits earthwork edge elevation engineer equal equation example field formula full stations G₁ G₂ grade gradient ground highway horizontal inverse program layout length maximum measured method middle ordinates mmmmm mmmmm mmmmm offset offset curve osculating circle parabola pavement Pennsylvania Turnpike Photogrammetry R₁ radius railroad reconnaissance result reverse curve route surveying scale setup side friction sight distance simple curve simple spiral SINE COSINE VERSINE stereoplotter subchords superelevation T₁ TABLE XX.-NATURAL SINES TANGENT 1 SEC tape terrain transit traverse triangle values vers VERSINE EXSEC TANGENT vertical curve yd³