Attachments: rasbeatriz.RASexport.sdf (107.6 KB)
thank you for the input. Sorry I was unable to answer earlier.
I will look into your SDF and report back.
As far as I remember, there isn't a tin layer implemented in MapWindow yet. There is/was a Tin Viewer plugin though. In the HEC-RAS utilities I created I use the tin to create the WSE and then convert it to a grid for the flood calculation.
This alpha release is meant to raise good comments like yours, so I can review the plugin for the next release. So I really appreciate your input.
Thanks again and standby for the next release. :)
Christian Degrassi, MA
This is a great plugin. Thanks for all your work on development. I am very appreciative. I have also sent you an email, but I will post here in case you might see this first.
I am very interested in a step-by-step usage guide/tutorial/example. I do not have access to ESRI software, so I am not familiar with the HEC-GeoRAS process. However, I have tried my hardest to scour for any guidance I can find, which is mostly in your release notes in the README.txt with the distribution. I've also read the HEC-GeoRAS Users Manual as you mentioned in the readme, trying to understand the process of preparing the geometry for import into HEC-RAS. But unfortunately there are some things which are not inherently obvious to me.
Would you be able to give me a quick pointer or two? OK, so here's what I've done so far.
- I have a working DEM, and I used it with the AWD/TauDEM plugin to determine the Stream Reach Shapefile.
- I then did "Create Base Layers", saving the HEC-RAS layer files into their own separate folder
- I then did "River to Flowpath", selecting the newly-created Flowpath.shp, and for "River" I used the Stream Reach Shapefile created by AWD/TauDEM
- OK, so now I am pretty sure I should do the steps in "RAS Export Pre-Process"...
- I assume this requires me to first create some Stream Network lines in the River.shp, (and afterwards then select River.shp for "Stream Network") Is this correct?
- DTM is obvious, I select my DEM
- "Nodes (Output)" - I believe this is an output file which gets written with the X, Y, Z output points of the Stream Network line vertices, right?
- For "Cross Sections", I added some cross-section lines to the XSCutlines.shp file. I added sections lines across and perpendicular to the stream path, at each of the Stream Network (River.shp) line vertices/nodes.
- For "River", I select the "River.shp" file
- When I press "Process", all that seems to happen is the XSCutlines.dbf file gets updated with some values in the "ProfileM" column. Is this correct? Or did I neglect to do something? (I have a feeling I am missing something here.)
- For "Cross Sections" I select my XSCutlines.shp file
- For "Flow Path", I select "FlowPath.shp"
- I then press "Process", but I get a small error dialog-box, "Specified cast is not valid". I assume I have neglected to enter some required data, or something to that effect.
I would truly appreciate any guidance. I have tried to get this figured out without asking you, but I've hit a dead-end. Sorry to pester with what might be stupid questions. I think most people probably have experience with HEC-GeoRAS and therefore know the process better. But once you clue me in, I would be happy to help write some step-by-step basic usage instructions.
thank you for the comments and the updates.
I got your emails and I figured out you are missing some features in the flowpath shapefile.
Currently you have only one line (Channel), but to generate LLegnth, RLength, etc, the flowpath must also contain a Left and a Right path. Please consult the HEC-RAS manual or the HEC-GeoRAS to learn about the best practice on defining these additional two lines. There are some guidelines, but in most cases buffering the Channel to a fixed distance might be good enough for a fairly regular channel. The buffer distance depends on the hydraulic properties of the channel and the location of the estimated floodplain.
Please try and let me know
Christian Degrassi, MA
Thank you very much. Yes, that cleared it up. Indeed, I did not realize I needed a "Left" and "Right" path in the Flowpath layer. Mention of this is brief in the HEC-GeoRAS manual and I missed it. I added those features, and the LLength and RLength fields were calculated by the "Reach Lengths" step.
I'll be using this plugin regularly, so I'll be in touch again soon with some other questions/suggestions...