Ras Mapper – XS Interpolation Surfaces

[ElisaLU]

Hi, I have a complex river model (with more than 1000 XS – most of them are interpolated) with 1D river bed and 2D flow areas and I cannot load the layers XS and XS Interpolation Surfaces on Ras-Mapper because it freezes and I need to close HEC-Ras and open it again. If I run an unsteady flow simulation, it stops on the step “Computing XS interpolation surfaces”. Anyone knows if the layers are not loaded on Ras Mapper this could cause problems on the unsteady flow simulation? Does the XS layers need to be loaded on Ras Mapper?
Anyone has a solution for this?
Thank you!

[rsbe]

I came across this problem as well some time ago (that RAS Mapper freezes when trying to figure out the XS interpolation surfaces). As far as I remember the problem was that one cross section was outside the stream centerline and had no place to go. So make sure every cross section lies on the centerline. There is no need to load the layers in the RAS Mapper by yourself, if you hose to model floodplain mapping, Ras Mapper adds the necessary geometry by itself . It will then show up under results once you have fixed the other problem…

[Anonymous]

I’m getting a similar issue: when running a steady flow analysis using HEC-RAS v5.0.3, the model hangs up at the “Writing Geometry – Computing XS Interpolation Surfaces” step. I’ve let it run overnight and it made no progress.

More details: this was a model I received from another party. The original, unmodified model runs just fine. I modified the original model by adding some new cross-sections and deleting some others. The modified model will run fine in HEC-RAS v4.1.0. Unfortunately, I need the floodplain mapping capabilities of v5 so I’m trying to get it to work.

Any thoughts on possible solutions?

[Anonymous]

I am having the same issue. I am importing geometry data using Geo-Ras and can’t get any of my models to run with 5.0.3. I am reverting back to 4.1.0 in order to push my project along. Any solution found?

[Ski907]

We just had the same issue pop up last week. We were able to run our model in 4.1, but not in 5.0.3. RasMapper froze in 4.1 when we tried to do inundation boundaries, so it seems like it only ran in 4.1 because the XS Interpolation Surfaces are not calculated as part of the initial calculation as they are in 5.0.3.

We spent a while sorting our specific issue out, but we were able to get it to run and generate the XS Interpolation Surfaces by increasing the distance between our bank station points, i.e. moving them further away from the channel center. We took this to mean that there was some problem generating the TIN used for the XS Interpolation Surfaces when the bank stations are too “tight” around the channel.

Hope this helps!

[Anonymous]

Wow, that is interesting that moving the bank stations resolved the issue. If that is really the issue that is a major problem for modeling some of these tiny tributaries we are doing. I wouldn’t want to move the bank stations on those, since that would affect n-values, and the results wouldn’t necessarily reflect reality as we are trying to model it…

[Igloo_79]

I faced the same problem after redrawing my centreline to more closely match the meandering channel planform. Tried deleting overlapping XS and restraightening the centreline, but no joy.

So I imported XS gradually reach by reach, eventually identifying a single XS causing Mapper to crash – the centreline was close to the L bank stn, so I moved the centreline away slightly – and problem solved!

[Anonymous]

I had the same issue with my geometry with over 200 xs cut lines. I tried to identify the problem causing xs cut line. But I figured out it were multiple.

My solution for the problem was: Tools -> XS Interpolation: Within a Reach

Apparently the differences between my xs cut lines were to great (whether this was height, distance or width I don’t know).

By adding interpoled xs cut lines for the whole reach, I fixed all the problems.

[Anonymous]

I ran into the same issue with a model. The model would not run in 5.0.3 but would run in 4.1. I got 5.0.3 working by initially running the model in 5.0.1. After that it ran fine in 5.0.3. I did tweak a few bank stations which may have had some impact as well.

Mike

[Author]

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