3.4.18 Breaklines

Last Updated: 16 March 2018         For: OptiSurface Designer V2.5+

  Breaklines are used to manually edit the topography by adding a line that allows sharp changes in the elevation.  It can be used to fix areas in the Existing Topography and should be used before calculation.  It can also be used to modify the design after calculation such as defining channels or levees.

Breaklines can be imported into OptiSurface Designer in .txt, .xyz and .ags files. The point code must start with '2' or 'L' and have more than one points in a row to be recognized as as a breakline.
40.12055032, -89.20666277, 193.875, L01
40.12747066, -89.20687957, 191.686, L01
40.12789400, -89.19292734, 193.874, L01
40.12135870, -89.19275350, 193.876, L01

Displayed by:
Menu: Tools > Existing Topography > Add Breakline or Tools > Proposed Topography > Add Breakline


For Existing Topography:

For Proposed Topography:

After pressing 'Add Breakline', left click on the surface and draw a line with a minimum of two points and double click to finish the line then hit OK.

Edit Breakline:

Double Click
  • Generated Point Spacing Along the Line (m):  Defines the distance between points along the breakline. These points will be triangulated into the topographic surface. If the points are too far apart, the triangulation may not give desired results. To correct this, reduce the point spacing value.
  • Edit Breakline:  When clicked, breakline becomes dashed line and enables drag and drop of breakline points to new location while in the Map Window.
  • Delete Breakline:  Delete the breakline.

Right Click

  • Edit Breakline - breakline becomes dashed line enabling drag and drop of the points or vertices.  While in Edit Mode, the Profile (see below) will also be shown.  Right click the dashed line to Edit Breakline Points Table (see below), Delete Point and Insert Point.

  • Edit Breakline Points Table - edit points of the breakline by modifying coordinates, elevation or slope in the table, also opens up the profile of the breakline.

  • Copy Breakline - copy the breakline to the Existing or Proposed Topography and shift to a new location.

  • Move Breakline - move the breakline to a new location.

  • Delete Breakline - delete the breakline.
  • Offset Breakline - offset the breakline; useful in creating the base for channels or levees.

  • Batter Breakline - opens up a submenu to batter the selected breakline to the surface, useful for drain channels and levees. 
    1. Define the Slope Ratios - 'Up' if breakline is below surface e.g drain channels; 'Down' for levees.
    2. Slope to Nearest is best used for roads, which can be both below or above the surface.
    3. Slope Direction - refers to the 'Left' or 'Right' of the clicked breakline, usually best to select 'Both' then delete the unwanted batter.
    4. Slope To - select the surface where the breakline will be created
    5. Max Distance - usually the same as the breakline being battered
    6. Auto Interval - use 5m or 15ft.

  • Plot Profile - plots the profile of the breakline, automatically opens up when editing a breakline to adjust elevation of the points in the profile window by click and drag of points or vertices.

    1.  Add Reference Line, Curved Line or Offset Line.

    2.  Calculate Flow - see 3.4.10 Profile.
    3.  Export - export the profile as image.
    4. Edit Breakline - adjust the elevation of breaklines points by click and drag.

    5.  Edit Breakline Table - opens the breakline table as shown above.
    6.  Autoscale Axes - adjust the axis scales automatically to cover all points for the Bottom Axis (Horizontal Distance) or Left Axis (Elevation) or Both.  This is useful when the Profile is zoomed in.
    7.  Zoom In/Out - zoom in by drawing a window using the middle mouse button and dragging from left to right covering the area to be zoomed in.  Drag middle mouse button from right to left to zoom out.

    8. Flip - flips the Profile view

  • Properties - opens up Breakline Properties dialog as shown above.

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