Wednesday, October 19, 2016

Creating Static Results Maps (Shapefiles or Rasters) using RAS Mapper

Written by Mikell Warms  |  WEST Consultants
Copyright © The RAS Solution.  2016.  All rights reserved.
Many readers have been asking how to create shapefiles and other static maps in RAS Mapper. One of the main differences between RAS Mapper in RAS 4.1 and RAS 5.0 is the existence of Dynamic Maps. What makes these maps dynamic is that when you have that Results Layer selected in RAS Mapper, you can use the slider bar (top right) to animate through the simulation and see the results of that layer at each mapping output interval (or each profile for steady flow models). These maps are not saved to the disk, they are temporarily stored in memory.



With this change, you can no longer “Export Layer to Shapefile” as you could previously, due to the fact that these dynamic layers are not one map, they are many maps.

To create static maps, such as shapefiles or rasters, we must first tell RAS Mapper what type of static map we want (Inundation Boundary, Velocity, Shear Stress, etc.) and whether we want the data from a specific timestep, or max/min. To do this, right click on the bold “Results” heading in the Layer Manager in RAS Mapper, then choose “Manage Results Maps”.  All of your plans and default layers will load (like below):


Choose the plan you are interested in, and click on “Add New Map.”

If you’re running a Steady model, the window that pops up will look like this: 

If you’re running an Unsteady model, the window that pops up will look like this: 

Choose the Map Type you are interested in creating; in this case we are creating a maximum Inundation Boundary. Notice we have chosen “Maximum” under the Unsteady Profile options, but we could have chosen “Minimum” or a specific point in time. On the right hand side of the window, make sure to change the Map Output Mode to one of the “Stored (saved to disk)” options, depending on your needs. In this case, we are creating a shapefile polygon. Then click Add Map.

One last step. The Manage Results Maps layer should now look like below:


Notice the static map we have added has appeared. However, the Inundation Boundary map status says “Map Not Created”. You will need to select that map, and click on “Compute/Update Stored Maps” at the top right. If you have multiple static maps, you can select them all by holding the CTRL key and selecting multiple maps prior to computing them.

Once the computations have completed, the status will change to “Map files up to date” and RAS will save your shapefile in your HEC-RAS project folder, in a subfolder that has the same name as the plan from which the shapefiles were created.


27 comments:

  1. Has anyone had any luck getting saved maps using the"Hybrid" water surface rendering that is new with Version 5.0.3? No matter what I set the Render Mode Option to, my saved maps (rasters, shapefiles) come out as the old "Sloping (Interpolated Values)" rendering mode.

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    Replies
    1. I haven't tried yet. But that sounds like it could be a bug. Would you mind sending a bug report to HEC on that one?

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    2. I submitted a report to HEC.RAS@usace.army.mil and got a response last week:

      "Thank you for reporting this problem. I have been able to reproduce the issue here with a separate dataset and have submitted the bug to our development team. The bug should be corrected in the next HEC-RAS release."

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    3. Thanks for doing that Derek.
      -Chris

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  2. Hi Chris, I am currently experimenting with purely the 2D modeling function of HEC-RAS. I have several areas that show flow splits in different directions. Is there a way to quantify how much Q goes in which direction? Any advice will be appreciated!

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    Replies
    1. Hi Chris. Yes, in Version 5.0.3 you can draw profile lines in RAS Mapper and use them as transects to extract flow data. It's really easy. Profile lines can be drawn using the Profile lines tab in the lower left hand corner of the RAS Mapper window.

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  3. Hi Chris, I am trying to create a hydraulic connection between 2 2D flow areas using a weir and culvert combination in RAS 2D. But everytime I attempt to run a simulation, I get the following error message. Do you have any advice?
    Plan: 'Unsteady Run with 2D Flow Interior Area' (GI_FINAL_2D.p07)
    Simulation started at: 26Jan2015 01:55:39 PM
    Using 64 Bit Computation Engines

    Writing Geometry
    Completed writing geometry

    Geometric Preprocessor HEC-RAS 5.0.0 Beta October 2014
    2 Internal Boundary curve(s) have been read in

    Finished Processing Geometry

    Writing event conditions
    Event conditions complete

    Performing Unsteady Flow Simulation HEC-RAS 5.0.0 Beta October 2014

    forrtl: severe (157): Program Exception - access violation
    Image PC Routine Line Source
    RasUnsteady64.exe 00000001401F62E2 Unknown Unknown Unknown
    RasUnsteady64.exe 00000001401D649F Unknown Unknown Unknown
    RasUnsteady64.exe 00000001401B9207 Unknown Unknown Unknown
    RasUnsteady64.exe 00000001401B2F2D Unknown Unknown Unknown
    RasUnsteady64.exe 00000001401B2C4A Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FF880BB Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FEF2ECA Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FFC557C Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FF102DC Unknown Unknown Unknown
    RasUnsteady64.exe 0000000140078B48 Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FF6CDC6 Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FEBEF5E Unknown Unknown Unknown
    RasUnsteady64.exe 000000013FEE41CE Unknown Unknown Unknown
    RasUnsteady64.exe 0000000140794AC6 Unknown Unknown Unknown
    RasUnsteady64.exe 0000000140344D82 Unknown Unknown Unknown
    kernel32.dll 0000000076B959ED Unknown Unknown Unknown
    ntdll.dll 0000000076DCC541 Unknown Unknown Unknown
    forrtl: severe (157): Program Exception - access violation

    Error with program: RasUnsteady64.exe Exit Code = 157

    ReplyDelete
    Replies
    1. Try saving, closing, and reopening RAS, then run again. If that doesn't fix it, then I'd have to see your data set to have a chance to figure it out.

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  4. I have a question concerning inundation mapping. In the first picture you showed above it seems to me that the inundation mapping is not limited to where I have cross sections. However, in my model, inundation mapping is limited to where I have cross sections and it looks like ras mapper would connect the outward points of every cross section and then, only calculate the difference between the Terrain and the WSE within this "polygon". But i would like the ras mapper to inundate everything around the river which is below WSE, even if there this place is "outside of the cross section range". Thank you for your advice.

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    Replies
    1. RAS only gets results where you have cross sections or 2D areas. Outside of these areas it can't map, because it doesn't have any data to map. You could try to manually expand your floodplain by following contours in ArcGIS if you really want to do this. Or you could extend your cross sections to cover the full area that gets wet. This is what you should do anyway.

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  5. Hi Chris,

    When I'm running an unsteady 2D flow model, is there a way to have HEC-RAS produce the shear stress map in RAS Mapper in it's initial run along with depth, velocity, and WSE? It's just when I add the shear stress map layer after I've run the model, it takes almost as long to produce the shear stress map as it does to run the initial model (which for larger projects with smaller time steps can be over an hour). I was hoping there was a way to define the maps that HEC-RAS automatically produces with each run. Thanks for your help!

    Regards,
    Jeremy

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    Replies
    1. I'm not sure if there is a way to do that. Strange that it takes so long to produce the map. I've never had a map take longer than a couple of seconds to compute.

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  6. Hi Chris,

    I've had some troubles in creating static results maps. Sometimes, when I'm trying to creating a map the program break down and I recieve this message: "System.OutOfMemoryException".

    Do you know what can be happening?

    Thank you!!

    ReplyDelete
    Replies
    1. Sounds to me that you are running out of memory to make that map. I would make sure you have enough space on your hard drive and that the map is not too large (in MB). You might try a larger mesh size and see if that helps.

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  7. Has any one had luck creating and storing maps for multiple runs (rather than creating one at a time as discussed). If not possible in HEC-RAS Mappers GUI, any luck in HEC-RAS Controller?

    Thanks!

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    Replies
    1. Ben, see if this is what you are after: http://hecrasmodel.blogspot.com/2016/03/post-processing-with-ras-mapper.html

      Chris

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  8. i am facing issues in generating mesh i don't know why ? as i am trying to model a part of indus river pakistan and exactly following the method which most of tutorials do but the problem comes when i try to generate the mesh in 2d flow area after identifying the polygon as well. when i got to the 2d flow area and click generate computation points on regular interval tab a window open and i put there x and y values and click generate than nothing happen and on the earlier window same line is mention that current mesh contains no computation points. can any body please giude me how to resolve this issue ??

    ReplyDelete
    Replies
    1. I had this problem when trying to use a mesh and cellsize that resulted in over 3,000,000 cells. Instead of showing me the cell count - the mesh builder would show nothing. In reducing cells to 1,000,000 i was able to get the mesh builder to work. 1,000,000 seems to me to be an upper limit. Others have reported higher cell counts, but on my machine I can't achieve that - despite system resources having plenty of RAM/CPU on hand.

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  9. Hi Chris,

    I'm having issues with extremely high shear stress values in my 2-D model. And by high, I mean 1,400 lbs/sq high! The study reach is about 4,000 LF, the valley slope ranges from 0.5-2 percent, I have a mesh cell size of 4'x4', and am using a time step of 2 seconds for 24 hour storm events. A majority of the mesh cells give realistic shear values (0.69 lb/sq) that are anticipated based on the desgin, but then I'll have a random mesh cell with a shear stress in the thousands. The surface was built from field run topo and I've checked it for errors, and it appears to be fine. I was wondering if you've ever had this problem before, and if any of my input parameters should be adjusted to give me realistic results. And I've had this problem on several projects, so I was hoping to figure it out seeing my clients don't like seeing bright red spots on my shear stress map!

    I appreciate your time, knowledge, and help!

    Thanks,
    Jeremy

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    Replies
    1. Jeremy- I seem to recall seeing that before but can't remember the issue. You're using 5.0.3, right? Can you send me your dataset and I'll see your if I can figure it out?

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  10. Chris,

    I finally figured it out. It was an issue with the land cover shapefile that I used. I wanted to model the trees on the floodplain, so I included them in the land cover and gave them an extremely high manning's "n" value with the hopes that I could see the flow diverging around them. What really happened is that the cells with the trees showed extremely high shear stresses. Is there a better way to show the trees in the floodplain? Including them in the surface? Or should I just adjust the manning's "n" to account for the trees?

    Thanks,
    Jeremy

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  11. Chris,

    I have a good working 2D model and am attempting to export a maximum shear stress raster. I save and compute the stored map as outlined in this post, and it creates a .TIF file and a .VRT file. The issue is I can't find any way to open/view the .TIF

    I've tried several different projects with different base terrain files, so I'm assuming it is something wrong with the TIF being created. Any ideas?

    Thanks

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    Replies
    1. You can save it as a static shapefile, which would allow you to view it in any GIS program.

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    2. When you say save as static shapefile, does that mean selecting 'polygon at boundary value' under 'Stored (saved to disk)'? Won't this just give me a boundary of the shear stress surface, not an actual representation of the shear?

      Ideally I would like to be able to bring the max shear .TIF into CAD as an image or import as a geotiff and have an actual surface.

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    3. You should be able to see the geotiff as a raster in CAD or ArcGIS. I wonder if there is a bug with creating the shrear stress map. Can you get a raster map of another output type (say depth or velocity)?

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  12. That's what I thought at first, but same issue with water depth and velocity .TIFs

    I'm running 5.0.3, I was going to try 5.0 and see if that makes a difference.

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  13. Hi Chris,

    Have you come across a way of exporting out the WSE or depth grids for horizontal rendering? I see in the post on 11/10/16 by Derek Etkin that HEC realizes this as a bug. Have you come up with any work arounds? We know that the sloping water surface allows neighboring cells to drag results up or down, the rendered images are not true to the water volumes computed by the RAS 2D engine, and errors can be dramatic in steep terrain with shallow flow. Thus, I assume we need to be cautious whenever presenting depth grids exported from RAS Mapper to clients, because they may not be accurate. And even if we could export depth grids with horizontal rendering, this may show artificial stairstepping.

    We are considering the following approach and were wondering if you had any thoughts: We export the WSE with horizontal rendering as a point shapefile for each 2D cell (or extract them from the HDF file). We open the file in GIS and for points with a value of 0, we assign them the underlying terrain elevation value. We convert the TIN to a raster, using the Natural Neighbors method, with a cell size the same as the terrain. Then using raster calculator, we subtract the terrain from the WSE raster, to develop a depth grid.

    Final question... is there a way to extract WSE along the edges of cells? This might help with improving our method.

    Thanks!

    ReplyDelete