3

Based on "Generating a series of cross sections (profiles) along a line?" post, how can I force the cross-section lines to be created, thus collecting elevation data, from LEFT to RIGHT facing the downstream end of the river based on the example @StevenKay has provided?

I see that it depends on the CRS, but is there a way to actually force them?

I need to import the cross-sections of a river in HEC-RAS 2D and they need to be created specifically in such way from the beginning.

I am using QGIS 3.6.

Improve this question
2
  • I know there is a function in HEC-RAS 2D ver 5.0.7 -> Geometric Data -> GIS tools -> GIS cut lines -> Reverse cut lines which allows you to switch direction of all or some of the cross sections. But I was still wondering whether there is an integrated function in QGIS for time management purposes.
    – Overlord84
    Commented May 2, 2019 at 1:59
  • Yes, there is plugin to do so: Swap Vector Direction
    – Marco
    Commented May 2, 2019 at 19:18

1 Answer 1

Reset to default
0

I cannot answer your specific question, but I can help you to cope with the task.

I do not create cross sections automatically, but one by one, even then it is hard to keep the consistency and it is quite common the end with a couple of cross sections with the opposite direction.

Adjusting the cross section breakpoints to match the expected flow lines and avoiding intersections is already time consuming, so I think correcting the direction is a minor task compared with the whole process.

To find the wrong ones, the ones with the inverted direction, I just use the "arrow style" for the lines. Once I found them, I reverse the order with the plugin "Swap Vector Direction".

Improve this answer
1
  • All I needed I think was that "Swap Vector Direction" plugin. Unfortunately, I cannot spend hours creating cross sections for rivers that are hundreds of km long. I'd much rather spend a bit more time creating a precise centreline and use the "Cross profile" function, and then re arrange the weird ones manually and then swap direction. Done ;)
    – Overlord84
    Commented May 3, 2019 at 0:15

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.