Extending 1D sections in RAS mapper

[Kate Bradbrook]

Hello, I often want to extend surveyed 1D sections using data from LiDAR whilst retaining the original survey points in the channel. So ideally, I want to add extensions to the existing XS lines WITHOUT changing these lines. I have discovered that this works really well for the Right Bank if I select the XS line with the “Edit Feature” button active, but then change to the “Add Feature”, it gives me a new line snapped onto the end of the existing line and when I finish editing that, it is still all one line. But how do I do this for the left bank? I’m sure it must be there somewhere and probably really simple trick I’m missing? Currently, I’m having to add new vertices to existing line and then dragging end point, but this does risk changing existing line slightly. Can anyone help me here?

[uke]

This functionality is currently very limited. There are still several options. These two should do the trick:
1. after finishing with the extension of your Right bank, reverse your cross section stationing so that right bank becomes left and vice versa. Extend your new right bank (old left bank). At the end, reverse cross section stationing again (kind of a dumm approach but it works)
2. prepare cross section “lines” outside of HecRas. Then you have the option to update elevation data from terrain on overbanks only

[Kate Bradbrook]

Thanks. It worked if I did the reversal in the geometry editor. Trying to reverse in RAS Mapper didn’t seem to actually change the line direction (maybe because it “knows” the downstream direction?).

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