Although one should consider a number of things such If you are reading this article, you may be considering agricultural engineering as your area of study. If this is the case, this blog post will give you a more solid understanding of what life is Geographic Coordinate System A geographic coordinate system represents the Earth using a three-dimensional 3D spherical surface.
Geographic coordinate systems are also called global or spherical coordinate systems. Projected Coordinate System In contrast to a geographic coordinate system, a projected coordinate system is based on a map projection. Some of the most common types of map projects are discussed below. Equal Area Projections An equal area projection is designed to maintain the area of specific features. Conformal Projections Conformal projections maintain the shape of a small area.
Equidistant Projections An equidistant projection maintains the scene along one or more lines. Azimuthal Projections Azimuthal projections plots preserve the direction from one point to all others.
For this projection, each great circle is mapped to a straight line. Seismologists frequently use this projection because seismic waves travel along circles. It is also a projection that is used for navigation. This is one of the oldest map projections used today.
The gnomonic projection is not equal area or equidistant. Message 4 of I'm using C3D Message 5 of Message 6 of Thanks Matt. That was my problem in this case. Message 7 of Conor, I think this error occurs only with alignments that have curves in them. Its tedious but effective, is there an easier way to convert an alignment to a polyline?
Does this problem still exist in ? Message 8 of Message 9 of If you want to export more that one alignment at the same time how do you do it? Message 10 of Here's another way to decurve a pline.
John Mayo, PE. Message 11 of Results from above. This causes the flood wave will steepen. On the other hand, you can also place cross sections too far apart. When you place cross sections far apart, this can result in significant changes in hydraulic properties. Placing cross sections too far apart can also cause the peak flow to be underestimated on the downstream end of the model.
Gary Brunner, a well-known modeler in the HEC-RAS community, recommends using the following equations to determine cross section spacing. If your cross sections are too close together, consider deleting some of your sections. If your cross sections are too far apart, and you do not have the data to cut more, add interpolated cross sections. You can do this by clicking Tools in the Geometric Data Editor. Then select XS Interpolation. Interpolated cross sections are shown in green in the Cross Section Viewer.
Additional cross sections are typically required in steep reaches where supercritical flow is possible, slope changes i. A higher value 1. However, applying a value of 0. This is because a theta weighting factor of 1.
Lee, — RAS Solution. When you are initially setting up your unsteady model, use a value of 1. Once you have stabilized other aspects of the model, try lowering the theta weighting factor.
As you lower the theta weighting factor, pay attention to how this impacts the results. Keep in mind that it may take several iterations to find an appropriate theta weighting factor. If your unsteady HEC-RAS model is fairly complex, you will probably not be able to get the theta weighting factor down to 0.
In these cases, a theta weighting factor around 0. To adjust the theta weighting factor, open the Unsteady Flow Analysis dialog box. Open the Options menu and click Calculation Options and Tolerances.
In addition to the theta weighting factor, you can also try adjusting other computational tolerances e. Increasing the tolerances will result in more convergence. However, in my experience, increasing these values does not seem to significantly impact model stability.
The hydraulic parameters considered include conveyance, flow area, top width, and storage. Making sure that your HTab Parameters are set up correctly will result in more accurate hydraulic curves. Halla, could you fix it anyhow? Or does somebody else knows a solution?
Thank you for help! Hi Halla, could you fix the problem? I get the same message and would be happy to find a solution Can anyone help??? Sediment Transport Analysis Sediment Output Options. Chris G. It's a binary file, so it's not readable in a text editor. Best option is to view the computation level output plots and tables directly in RAS View Quick question.
I can tell that the coordinates are in UTM. How can I assign this projection to it? I see the option to "Define Projection", but it is asking for a prj file, which is exactly what I don't have. Yes, you need to get a. I cant see the water profile results: a windows message apears "Error loading output data for profile plot" dou you have some advices?
Sometimes it helps to shut your computer down and reboot. But most of the time when I've seen that message, it's because your model crashed before it could make an output profile. In that case, you'll need to stabilize your model first. Chris, you might want to report this as a bug to HEC. Hello, I find your blog pretty interesting. Fortunately I'm working as modeller, then I visit it very often. But I don't like to erase important information.
I have a lot of files with the word "scratch". They aren't important, are they? How could I do, please? You can get rid of all of the "scratch" files. They'll be regenerated when you compute again. In fact, you can get rid of all files that are not input files.
If you're looking to clean up your folder, you can delete everything except for the. Everything else is recreated when you compute. Thanks Chris, that's really useful information for us. Yes, most notably the geometry and plan hdf files, as well as the rasmapper file. The geometry hdf file.
The plan hdf file. Hello, Does anyone know where I can find details of the contents of the plan and geometry. For example, in my. X,Y,Z are easy to understand, but what is the M value used for? Max, as you've discovered, the HDF file has a lot in it and much of it is a mystery. I'm not sure what the A and M values represent. I wonder if you Googled around a bit, you could find out?
Let us know if you do! Thanks for your answer. I will try it during next days. Another question please. How can I delete several plans or geometries at the same time? In the geometry window, you can go to File Delete Geometry. In the Unsteady Analysis Window, you can go to File Delete Plan. I believe you can only do one at a time this way, but it's very fast. Now if you so many that you don't want to use the File Delete command, you can always go to windows explorer and delete multiple geometry and plan files.
But so that RAS isn't looking for those files the next time you boot up the software, you can go into the. Thank you. I have a planty of them. Then I would like to delete several at the same time. DSC" file type. It that important? Can I delete it without having problems later? It's what I call a "convenience" file in that it is not necessary to have, but could be useful if you want to see all of your DSS boundary condition pathnames in one place. Hello, I really enjoyed your blog. I do not speak English, I am using a translator.
I saw that the HEC only shows results in dynamic conditions concentrations varying over time of the constituents nutrients. However, I would like to simulate the water quality of the river in stationary conditions not time-varying. Is this possible? Thank you! RAS simulates the change in water quality through a system over time.
You have to come up with the initial conditions on your own. Hello, can I have one question? Is there a way how to get datas in this much shorter step? I mean if I can get them from any output file hec created?
Yes, you can get some of the data at smaller output intervals than 1 minute by checking the "Computation Level Output" on the Unsteady Flow Analysis window. This will give you output at the Computation Interval. Thanks DR. Thanks, so to see cross-section geometry, catchment rainfall-runoff properties etc I will need to see the prj files from HMS and RAS, correct? What should be the possible reason why I always got a result like that and how can I address that problem?
When you get a chance, can this be updated with the v. Great idea! I think I'll wait until the official version comes out, just in case they slip in a new file type between now and then.
In the meantime, is there a particular file or files you are wondering about? Hello I got a mesage that says "Error determining output format. Bad name or number" what does it means?
Could be any number of things. Most likely, your model is going unstable though and is therefore having trouble writing output. And, could anyone please tell me how do I interpret the results from the output of running a simulation model? Please read through the manual for suggestions on interpreting results. First of all, thank you for your website. You've saved me from punching through my computer on multiple occasions. At this point, I have to send my model to someone and until this moment I didn't realize that I had to send all of the files ie:.
Quite frankly, I'm embarrassed to send such a large file. Is there any way to "start over" with the numbers in the file name without having to do everything again? If not, is there a way to avoid this in the future? You can, but it involves manually renaming the files in windows explorer, then changing the associated file extensions in the prj and plan text files.
Hi Running a simple water analysis on a river connected to a storage area with a conservative tracer in the lake. I get this "Number of storage areas in hydrodynamics file does not match the number in the cross section properties file.
Any chance you know what might be going wrong? Hi Any chance you might know what this means "Number of storage areas in hydrodynamics file does not match the number in the cross section properties file. Nothing happens until I click "Stop" Cheers.
What RAS version are you running? If you are not already, use 5. Do I still need to upgrade? Only because it will be a hassle to get Admin Authorization, but can do it if need be. If you want to send me your dataset ill take a quick look to see if I can figure it out. Thank you very much for the offer.
I took my data home and ran the sim on the latest version and there was no longer any error. So, so far so good. Thank you for your help.
I'm trying to perform a water quality analysis and got the same error. When I disconnect the storage area from my reach the analysis can be performed. Are storage areas supported in wq analysis at all? Chris, I am trying to set up a 2D model and when ever I try to compute the mesh for the 2D flow area it says there are no computation points. Any idea on what I can do to fix this? The terrain is connected to the geometry. Have you entered your cell center spacing?
Hello, I am a master degree student. Model is runned sucessfully. I have done inundation using ArcGIS but not much area is inundated. Please reply me soon First, make sure you actually have the breach parameters input and you've selected the box that says "Breach This Structure".
Next, make sure that you've set your trigger failure so that the breach actually initiates. If you've set your trigger to a WS Elev, and your reservoir never gets that high, it won't breach.
You can check to see if it's breached by animating the cross section plot from the main RAS window, View Breach flow hydrographs are displayed in the flow and stage hydrograph output from the main RAS window, View Stage and Flow Hydrographs. Make sure in the stage and flow hydrograph plot to select the inline structure type by going to Type Inline Structures. Chris, You mention that the "computed results" are binary files. Is it possible to get the computed results in a.
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