Graphics Programs Reference
In-Depth Information
2.
On the Survey tab of the Toolspace, right-click Survey Databases and
select Set Working Folder.
3.
Browse to and select the
Chapter 04
class data folder. Click OK. You
should see a different survey database named
Essentials
.
4.
Right-click the
Essentials
survey database, and select Open For Edit.
5.
Expand the
Essentials
database. Right-click Figures, and select
Create Breaklines.
6.
Scan the list of figures, and note which ones are tagged as breaklines.
Click OK.
7.
In the Add Breaklines dialog box, change the Mid-ordinate Distance
value to
0.03
, and click OK.
Breaklines in the Field
As you study the list of figures in this exercise, are you wondering why some are
designated as breaklines and others are not? Breaklines are linear features that
mark a change in the slope of the ground. Some of these are quite obvious, such
as a set of bottom of bank (BOB) points or top of ditch (TOPD) points. Others serve
double duty, such as an edge of pavement (EP). This survey figure marks the line
where pavement ends and dirt begins, but typically there is also a change in slope
at this line between the slope of the ground and the manmade slope of the road.
For this reason, EPs are often tagged as breaklines. Other features obviously
have nothing to do with the slope of the ground, such as a right of way (ROW),
treeline (TL), and fence line (FENC); therefore, they aren't checked as breaklines.
You should notice a change in the contours along the red break-
lines. These breaklines define the swales, edges, and ridges that were
recognized in the field and explicitly located as terrain features. In
addition, notice that contours now cover the road area to the north.
The surface in this area is made strictly of breaklines.
8.
In the top-right viewport, click one of the surface contours, and then
click Surface Properties on the ribbon.
9.
On the Information tab of the Surface Properties dialog box, change
Surface Style to Triangles. Click OK. Notice how TIN lines don't cross
the breaklines.
