Extending Selected Cross Sections

The left, right or both ends of selected cross sections can be automatically extended by a specified distance. If one or more bank lines are also selected, you can also choose to extend the selected cross sections to the intersections with the nearest bank lines provided the bank lines are located within the specified distance. If any selected bank line is located outside of the specified distance, you can choose to extend the end of the cross section by the specified distance.

If a ground model has been loaded onto the GeoPlan, you can choose to set the maximum spacing between the new vertices on the extended cross sections. You can also choose if any new cross section vertices should have their elevation set according to the ground model heights. This is an extremely useful feature if you have surveyed data for e.g. a main river channel and you want to use ground model data to generate elevations across the floodplain.

Extending Cross Sections

To extend cross sections:

1. Select the following network objects on the GeoPlan:
• Any cross sections cross sections to be extended
• Any applicable bank lines (if the cross sections are to be extended relative to bank lines)
2. Ensure that the appropriate ground model is loaded on the GeoPlan if you want to have the heights of any newly generated cross section vertices automatically generated from the ground model, or want to set the spacing between the new vertices.
3. Choose Geometry | Extend cross sections from the Model menu. This displays the Extend Selected Cross Sections dialog:

   Show me

   

   The options enabled in the dialog depend on what items have been selected on the GeoPlan and whether or not a Ground Model is loaded. See the Extend Selected Cross Sections Dialog topic for further information about the available options.

4. Select the appropriate options in the dialog.
5. Click OK to carry out the extension of selected cross sections. The extension process is outlined in the Cross Section Extension Process section below.

   An Extend Cross Sections Report will be displayed reporting number of cross sections extended, the number of failures and the reasons for any failures.

Cross Section Extension Process

Selected cross sections will be extended according to the parameters set in the Extend Selected Cross Sections dialog. Vertices will be added to the extended sections as follows:

• When no bank survey lines have been selected on the GeoPlan and the Extend left/right distances beyond section ends option is selected on the dialog, then left/right cross section ends are extended to the full left/right distances specified in the Extend left side of section by / Extend right side of section by boxes on the dialog. Each section will be extended in the direction of the last segment of the section on the left/right side.
• When bank survey lines have been selected on the GeoPlan, and the Extend left/right distances to selected bank lines option is selected on the dialog, then left/right cross section ends are extended (in the direction of the last segment of the section on the left/right side) until a selected bank line is encountered within the range of the distances specified in the Extend left side of section by / Extend right side of section by boxes on the dialog. The left/right cross section is extended as far as the intersection point with this bank line. If more than one selected bank line lies within the range of the specified left/right distances, then the nearest bank line is used. If no bank line lie within the range for a particular cross section, then that cross section will not be extended.
• When bank survey lines have been selected on the GeoPlan, and the Extend left/right distances to selected bank lines or beyond section ends option is selected on the dialog, then left/right cross section ends are extended as described above. However, with this option, if no bank lines lie within the range, then the applicable cross sections will be extended by the full left/right distances specified in the Extend left side of section by and/or Extend right side of section by boxes.

The elevations of any newly added vertices will be null (unspecified) unless a ground model is loaded in the GeoPlan and the Populate extensions from ground model box is checked. In this case, the newly added vertices will have their elevations set to the ground model heights at those points.

If a ground model is loaded in the GeoPlan, and the Insert vertices on line extensions to give a maximum spacing of box is checked, additional points (with a maximum separation between them as specified on the dialog) are added to the cross section between the original left/right section end and the new left/right section end.