The String Longsection Editor allows you to view and modify existing road and terrace strings. The Editor consists of three viewing panels:

• Longsection Graph - Displays the string longsection plus additional strings and ground lines, as determined by the Display Settings.

• Cross-Section - Optional. Displays the cross-section at the cursor position on the longsection. Switch on in the Display Settings.

• Data Area - Displays longsection chainage, elevation and slope from the active string to it's parent string, as specified in the Display Settings.

You can zoom in/out of the longsection using the mouse wheel; or the Zoom Window icon on the toolbar.

The Status Bar at the bottom of the window displays the chainage, elevation and slope of the string, as well as the elevation of the ground at the cursor position.

Display Settings

This displays the string Display Settings, which determine which information is displayed in the longsection graph, optional cross-section graph and data area. You can select from other strings in the data set, ground lines extracted from the DTM, as well as what information to display in the data area.

Data Area Information

Specify which information must be displayed in the data area, as well as the optional cross-section display.

Editing Functions

You can change the elevation of individual vertex points as well as fit points along a grade, between two other vertices, along a curve through three points, or a curve of the specified radius.

You will be prompted in the prompt area when required. Click Save to save your changes to the string.

Click Print to print the longsection.

Move a Single Vertex

1. You are prompted to:

Move string vertex: Select a point

2. Click on a vertex.

3. You are prompted to:

Move string vertex: Indicate a new position

4. Drag the vertex to it's new position and click. Because you're editing the vertical alignment, it is only the elevation that is important and considered at all. The change will be reflected on the longsection view.

5. Press [Esc] to end the function.

Change Vertical Exaggeration

1. Enter the number at which you want the vertical extent to be a scaled-up factor of the horizontal scale.

2. Click OK.

Interpolate a Range of Vertices Between Two Points

1. You are prompted to:

Interpolate string vertices: Select a start point

2. Click on the first vertex at the start of the range to be graded between the two points.

3. You are prompted to:

Interpolate string vertices: Select an ending point

4. Click on the second point that will determine the range to be graded. All the vertices between the two points will be graded on a straight line between the first and second points.

Apply a Grade to a Range of Vertices

1. You are prompted to:

Grade string vertices: Select a start point

2. Click at the beginning of the range. This vertex will remain the same but is needed to indicate the starting position.

3. You are prompted to:

Grade string vertices: Select an ending point

4. The Grade String options display.

5. You can specify either the elevation at the end point, or the grade between the start and end points as a percentage or ratio slope.

6. Click OK to reflect the change in the Longsection view.

Smooth a Range of Vertices by a Vertical Curve

1. You are prompted to:

Vertical Smooth: Indicate start vertex of curve

2. Click at the beginning of the range. This vertex will remain the same but is needed to indicate the starting position.

3. You are prompted to:

Vertical Smooth: Indicate end vertex of curve

4. Click at the end of the range. The longsection graph will now display a preview of the smoothed curve as well as a confirmation message.

5. Click Yes and confirm that the string can be altered as displayed. What happens now is that the edge after the first indicated vertex and the edge before the second indicated vertex are used as tangents to a curve between those two vertices. All vertices between these two vertices are interpolated along this curve.

6. The change will be reflected on the longsection view.

Add a Vertical Curve by Curve Length

1. You are prompted to:

Vertical Smooth: Indicate start vertex of curve

2. Click at the beginning of the range. This vertex will remain the same but is needed to indicate the starting position.

3. You are prompted to:

Vertical Smooth: Indicate end vertex of curve

4. Click at the end of the range. The program will prompt you for a curve parabolic length.

5. Enter the desired curve length and click OK. The longsection graph now displays a preview of the smoothed curve, as well as a confirmation message.

6. Click Yes to confirm that the string can be altered as displayed. The string vertices will be updated to lie on a parabolic, vertical curve with the specified curve length. The change will be reflected on the longsection view.

Add a Vertical Curve by Three Points

1. You are prompted to:

Vertical Smooth: Indicate start vertex of curve

2. Click at the beginning of the range. This vertex remains the same but is needed to indicate the starting position.

3. You are prompted to:

Vertical Smooth: Indicate end vertex of curve

4. Click at the end of the range.

5. You are prompted to:

Vertical Smooth: Indicate a point on the curve

6. Click on a point that the desired curve must pass through.

7. Confirm that the string can be altered as displayed. The string vertices will be updated to lie on a parabolic curve, that is tangential to the indicated start and end vertices and that runs through the specified point. The change will be reflected on the longsection view.

Apply a Spline through a Point

Use this option to fit a spline. You are required to indicate two edges and a through point.

1. You are prompted to:

Indicate start vertex of spline

2. Indicate the vertex where the spline smoothing should start.

3. You are prompted to:

Indicate end vertex of spline

4. Indicate the vertex where the spline smoothing should end.

5. You are prompted to:

Indicate a point on the spline

6. Indicate a point that the spline should pass through. This can be any point on the screen, and not only vertices.

7. A spline will be added between the start and end vertex, passing through the indicated point.