Graphics Programs Reference
In-Depth Information
FiGuRE 9.9
A width or offset target (in red) applied to a
corridor to widen the lane and create a pull-off area
In addition to alignments, you can use feature lines, survey figures, and poly-
lines as width or offset targets. Lane widening is probably the most common
use of a width or offset target, but there are many other uses. For example, you
can use a width or offset target to control the location of a ditch, the width of a
shoulder, or the distance between a shoulder and a guardrail.
understanding Slope or Elevation targets
Slope or elevation targets
are used to control the elevations of one or more com-
ponents of a corridor. For example, these targets can control the elevations of a
roadside ditch to ensure that it drains to a specific point, regardless of the slope
of the adjacent road (see Figure 9.10). Profiles, feature lines, survey figures, and
3D polylines can be used as this type of target.
FiGuRE 9.10
The use of a profile (3D chain
shown in red) to control the elevations of a ditch
