Leica Geosystems TPS1100 Professional Series - Reference Manual - Manual (Page 198)

198
TPS1100 - Appl. Prog. Ref. Manual 2.2.0en Road+
Data Files, continued
Parabola defined by station
(chainage) and height of
starting point, and
parameters of parabola
2
(– = crest; + = dip)
End of
project
(EOP) station (chainage)
and height of end-point
of gradient
2 Parabola parameter formulae:
p=(S–S
0
) 2 / 2(H–H
0
)
Where:
S = any station (chainage) on the
parabola
S
0
= station (chainage) of the
high/low point of the
parabola
H = height at any station S
(above), and
H
0
= height of the high/low point of
the parabola
Where:
Y = The height of a point on the
vertical curve;
X = The horizontal distance of
the point from the beginning
of the vertical curve;
a = One half of the rate of
change of slope in the
vertical curve;
b = The slope of the vertical
alignment at the beginning of
the vertical curve, and;
c = The height above datum at
the beginning of the vertical
curve.
OR
p = L / (G
OUT
- G
IN
)
Where:
G
OUT
= the slope of the vertical
alignment at the end of the
vertical curve, expressed as
a decimal fraction (not
percent);
G
IN
= the slope of the vertical
alignment at the beginning of
the vertical curve, expressed
as a decimal fraction (not
percent), and;
L = the horizontal distance from
the beginning to the end of
the vertical curve.
OR
p = 1 / 2a,
in the general equation
Y = aX
2 + bX + c for a parabola as
used to describe a vertical curve in
an alignment.