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Cross
Sectional data may be generated through a variety of different methods,
namely :-
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By
Manual (keyboard) entry, |
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By
Interpolation when combining a Horizontal Alignment (Centre Line)
File and a Tacheometric File.
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The
use of a Horizontal Alignment File infers that the centre line
points are at regular intervals, and will lie along
mathematically correct geometric entities such as straight
lines, circular curves and transition (clothoid) curves. |
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The
two defined files must have a common area of overlap. Further
information such as the required Section chainage range, the
Section widths and interpolation distances along the Sections
may be entered. |
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This
method provides a technique of creating Cross Sections without
having to stake the Centre Line, or physically measuring the
Sectional data. This method is not suitable, however, for
terrain that contains man made features such as drains,
existing roads etc. |
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By
Interpolation when combining a Co-ordinate File and a Tacheometric
File.
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The
use of a Co-ordinate File makes allowance for "centre
line points" that need not be at regular intervals, and
may not necessarily lie along mathematically correct geometric
entities. |
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The
two defined files must have a common area of overlap. Further
information such as the required Section chainage range, the
Section widths and interpolation distances along the Sections
may be entered. Interpolation is carried out via a least
squares plane fitting technique. |
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As
for the previous method, this method also provides a technique
of creating Cross Sections without having to stake the Centre
Line, or physically measuring the Sectional data. This method
is not suitable, however, for terrain that contains man made
features such as drains, existing roads etc. |
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By
using a a Horizontal Alignment ( Centre Line) File plus extraction
of BreakLine Data from a Tacheometric File.
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This
option searches through a user defined Tacheometric File for
all BreakLine information, and then combines this information
with centre line information taken from a user defined
Horizontal Alignment File . |
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The
two defined files must have a common area of overlap. |
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Only
those points that represent intersections between a BreakLine
and defined cross sections will be added to the cross section
file. Hence, by manipulating BreakLines in a Tacheometric File
it is possible to pre-select features that will be reflected
on the cross sections. No interpolation will take place using
this Option. |
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This
method provides a technique of creating Cross Section
information on discreet topographical features without having
to stake the Centre Line, or physically measuring the
Sectional data, and is suitable for both natural terrain and
terrain that contains man made features such as drains,
existing roads etc. |
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Generate
Cross Sections using both Interpolation and BreakLine Data from a
Tacheometric File
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This
option uses the Centre Line data taken from a user defined
Horizontal Alignment File to position and orientate the cross
sections. It then searches the defined Tacheometric File for
all BreakLine Information, and combines this information with
least squares interpolated heights to supply the most complete
cross section information of all the options. |
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The
resulting Sections are more comprehensive than those of the
previous options, and hence take somewhat longer to generate. |
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This
method provides a technique of creating Cross Section
information on discreet topographical features, plus
interpolated heights, without having to stake the Centre Line,
or physically measuring the Sectional data, and is suitable
for both natural terrain and terrain that contains man made
features such as drains, existing roads etc. |
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Load
Cross Section Information held in a Tacheometric File.
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This
option combines information held in a user defined Horizontal
Alignment File and surveyed Sectional information held in a
user defined Tacheometric File . The two files must have a
common area of overlap. |
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Further
information such as required section widths and acceptable
Off-line tolerances along the sections must be entered. |
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This
method provides a technique for generating Cross Sections that
have been Surveyed using polar techniques and stored in, and
then transferred from, an electronic logger or Total Station.
This method requires that the centre line is staked and the
Sections are measured in the field and is, therefore, suitable
for terrain that contains man made features. |
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Load
Cross Section Data from a Handi-Data "LEVELS" format
ASCII File . |
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Using
this option the Cross Section data are read from an ASCII
File, set in the "HANDI-DATA SYSTEMS SURPAC" format.
This method provides direct reading and loading of data as
measured in the field. For further information on the ASCII
file format, refer to the "LEVELS" User's Guide for
the PSION Organiser, or for the PSION Workabout "DISK
Transfer". |
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Cross
Sections may be combined with a Vertical Curve Alignment File data created
through the Vertical Curve Alignment programme. If Design File information
is included, then the programme allows for the inclusion of user information
related to the construction of batter slopes, drainage channels etc.
This combination is used both for the plotting of Cross Sections, and the
generation of Sectional Volumes. |