The horizontal curve represents the alignment behavior in the XY plane. When calculated, it’s the default tab that will be shown when an alignment is selected. It is therefore the position of each element in space. All of the arcs depicted are tangents to the preceding and following elements, and if their radius is positive, they turn clockwise. In the following example (which is the curve from the PI example), the alignment starts with a line followed by an arc that starts at chaining 1830.776 with a radius of 800m turning counter clockwise, and ending at chaining 2290.102.
The horizontal curve tab has the same options as the PI tab, as well as the 
Table of columns in the Horizontal Align. tab:
Column | Description |
|---|---|
No | Sequential number in the current alignment. |
Chaining | Chaining of the current point. |
Eq.Ch. | A fixed value to replace the chaining value. This value is created during verification, and does not change the point's position in any way. |
Name | Point number in the descriptive file. |
X | X coordinate of the point. |
Y | Y coordinate of the point. |
PCode | PCode of the point. |
Element | Choose between: “Line”, “Arc”, “Spiral”, “Symmetric spiral” or “End” |
Param.Hor.Curve | The horizontal curve's parameters. View-only mode. |
It is possible to edit the horizontal curve here rather than with the PIs. Simply change the element's type to an event, and the next segment will change accordingly. You can also generate an alignment with non-tangent curves.
Element type options:
Option | Description | Interface |
|---|---|---|
Line | In the alignment, the current segment is straight. You can choose its next point or define its direction in degrees and its length. Tangent = calculate the last segment's direction and apply it to the current segment. | |
| Arc | In the alignment, the current segment is curved (arc element). It can be defined in several ways:
| |
| Spiral | In the alignment, the current segment is a spiral. It is defined by the following elements:
| |
| Symmetric spiral | In the alignment, the current segment is a spiral-arc-spiral combination. It is defined by the following elements:
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