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Chapter 3 Working with Profiles and Vertical Alignments
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Sampling the Existing Ground to Create the
Profile Data
To create a profile, you must first sample the existing ground from a surface, a
file, or from cross sections. You can also create existing ground data in the
Vertical Alignment Editor. Sampling the existing ground creates elevational
values for the profile.
Sampling the Existing Ground Profile Data from
a Surface
If you have an existing ground surface on which the horizontal alignment is
located, then you can use this existing ground surface to sample elevations for
the profile. The Sample From Surface command accesses the files that were
created when you originally generated the surface, and creates a file containing
existing ground elevations along the defined alignment. The existing ground
elevations are used in creating an existing ground profile.
To sample existing ground data from a surface
1 To sample the existing ground information from a surface, create at least one
surface using the Terrain Model Explorer.
To sample more than one surface, enable the use of multiple surfaces and create
a file that contains the multiple surface information.
2 Define the horizontal alignment with the Define From Entities or Define From
Polyline commands.
3 From the Profiles menu, choose Existing Ground ä Sample From Surface to
display the Select Surface dialog box.
If the current surface list is set to Volume Surface, select the Terrain Surface
radio button to change the surfaces displayed in the list.
4 Select the surface to sample, and then click OK.
If multiple surfaces are enabled, then the command retrieves and samples the
surfaces that you selected with the Select Multiple Surfaces command. The
Profile Sampling Settings dialog box is displayed.
5 Make changes to the sampling settings, and then click OK.
You are prompted to enter the beginning and ending stations to determine
which stations to sample.
6 Enter the starting and ending stations. The defaults are the starting and ending
stations of the alignment.
The command then processes the profile information for the specified station
range and displays the distance sampled in a statement similar to the following:
You have sampled profile for 3856.25 feet of alignment
The command creates a file that is named for the current alignment with an
extension of .vrt in the c:\Land Projects R2\<project name>\align\<alignment
name> folder. If a file with the same name already exists, then the command
displays a confirmation prompt to overwrite the previous definition.