<< Click to Display Table of Contents >> Navigation:  Design > Vertical > Extract geometry

Purpose

To annotate the geometry from the 2D Polyline representing the Vertical Alignment and write a .vtg file that stores the vertical geometry for use in subsequent String design functions. For normal use this 2D Polyline should start and end with identical chainages to the Horizontal Alignment and be drawn from left to right on a section with a 5 X vertical magnification. This would typically be run after menu item Design, Vertical, Curves. Alternatively a .vtg file can be created from a 3D Polyline.

 

Operation

Return to accept default of working on a section :-

Pick the datum line and pick the 2D Polyline representing the Vertical Alignment.

 

 

Level locations

For typical road design applications the Regular Chainage intervals and Vertices option is most suitable with an interval of 10.000.  

For a vertical design that has no arc elements such as a pipeline or drainage application then the setting should be "Polyline Vertices only".

Other options get the chainage locations from .lsc files (see menu item Horizontal, Extract Geometry) or .dat files (see menu item Overlay design). Options reading horizontal data from and .lsc file can also extract locations defined by special chainages i.e. Road centre lines (CLs), Tangent Points and Manholes.

 

Curve Specific  

A closer interval for chainages along curves can be set with "Arc Intensifiers".

Circular arcs on a section drawn with a vertical magnification of 5 are very suitable for most occasions but the "Use parabolic formula" will invoke parabolic geometry calculated at the specified interval with a fine tuning factor – if less than 1 this will be flatter and if greater than 1 it will "peak more".

 

Output options  

To store the vertical design for subsequent 3D String design functions a .vtg must be written. Enter the .vtg file name and an (optional) comment or reference.

The .vld file is a simple listing of chainages and levels and is not required for typical use. The .vta output extracts the vertical geometry's curve lengths, radii and IP information for somewhat more detailed analysis and is definitely not useful for typical user.

"Draw" needs to be "on" to annotate the design geometry. Ensure that it is located in appropriate boxes and lines etc. on the section type being used by settings in Section Setup...

 

Example .vld file :-

   0.000    87.405

   10.000    87.698

   20.000    87.991

   30.000    88.284

   40.000    88.577

   40.653    88.597         t

   50.000    88.837

   60.000    89.020

   70.000    89.128

   79.423    89.161         hi

   80.000    89.161

   90.000    89.120

  100.000    89.003

  104.299    88.930         t

  110.000    88.833

 

Example .vta file :-

KeyTERRA-FIRMA Vertical Geometry (ASCII) File

 

Start chainage -7.251798

Start level 95.252578

 

Curve length 172.993829, Radius -801.451365; IP chainage 251.691383, IP level 116.016889

Curve length 80.803474, Radius 374.235730; IP chainage 462.270506, IP level 87.127176

 

End chainage 646.318956

End level 101.897911

 

Alternatively click From a 3D Polyline at the initial dialogue, pick a 3D Polyline (representing a channel that a Lay-by is to be related to for example) and enter the output .vtg file name.