Jump to content
GMS, SMS, and WMS User Forum


  • Posts

  • Joined

  • Last visited

Everything posted by Dave72

  1. Perfect, thanks Chris. That Tc calculation is exactly what I needed to gain some confidence working in this model. Do you know the source / author of that equation?
  2. Thanks Chris, I am still uncertain which formula is used for Compute tc in the "Rational Method - IDF computation" box. I have the model set to "Rational". I changed the Time Computation Arc Attributes to the simplest I could find (New Mexico Shallow concentrated flow equation) that gives me 0.798hrs in the Time Computation Arc Attributes dialogue, and when I return to the Rational ยป Run Simulation and recalculate the intensity, the tc does not update to the 0.798hrs I saw in the other diaologue. If there is a better way to work these out with you, let me know. Thanks, Dave
  3. Chris, I am checking the recalculation and Tc is unchecked. I don't believe I selected anything past default when doing basin data. If it is on by default in the initial basin computation, then possibly. Other than that, I do not believe so. I am checking now if it is using max flow slope or max flow distance. Speaking of which, I've done a search on the wiki and the pdf manuals and cannot find definitions for: -Max Flow Length -Max Flow Distance -Max Flow Distance -Max Flow Slope Would you be able to shed some light on these? Dave Edit: I've done a quick check and the value being populated into the "Length" box on the" IDF computation" window (Compute tc) is the Maximum Flow Distance. Lastly, is there a way to send you a message on these forums?
  4. Hi Chris, 1. Okay 2. I will have to check confidentiality on this. I'll get back to you. Shouldn't be a problem. 3. So before closing, you are saying the units are being shown in feet. Then after closing and opening again they are shown in meters. From your link it appears that I need to manualy "create flow path arcs from selected points using the Node->Flow Arcs and Stream->Flow Arcs commands". However, I have not done this and a number is appearing in the "Length" box . This number, as noted, changes from 7000+ to 2165.04. Is this possibly a glitch because I did not define a flow arc? And if I don't define a flow arc, what is WMS using to populate this field. Is it a reliable number? (I am using a DEM coverage with basins defined). Is the only manual for WMS Rational Method the Wiki? Where would I find the supporting equations. I ask because I would like to see how the manning number is being used. This variable is not used in the accepted method we use for the rational method in our region and I need to verify it before using it (or at least report/reference it). And I should probably also verify it by hand before using it. A small additional question: In the "Drainage Data Computation Options", the following can be computed: 10/85% Slope for the Max Flow Distance Is it possible to display this slope using the "Drain Data Display Options" ? Thanks again, Dave
  5. Hello, I`ve been seeing some odd behavior from the rational method - IDF Computation dialogue boxes 1. When I switch to metric units, the change is not reflected in the "Input variables for IDF curves" dialogue box. 2. After entering values for IDF (i.e, 1:100 year storm values), when I close and reopen the project I have unusual numbers appearing. My original values are gone and replaced with IDF tables for all return intervals. Previously before closing I only had the values I entered with "No data computed yet" listed for the other user supplied data. 3. The Compute tc radial option has 3 variables. 2 are taken from the watershed data already calculated by WMS using DEM data. Mannings I enter. Slope appears correct and stable. Length changes when I close the rational method diologue boxes and reopen. The number changes from 7000+ to 2165.04. It is also not clear if the length number is metric or imperial. I have not been able to find a description of this parameter in the tutorials / manuals. I'm also curious how this rational method is related to the OC rational model and the Modrat model. Are there any links. Is there a manual for the WMS rational method included in the program? Thanks for you usual good service, Cheers, Dave
  6. Hi again Chris, I actually solved this problem last month but became occupied with another project and had to put the WMS work quickly aside. In the meantime I've become foggy on what exactly was causing the issue but have a feeling it was due to not removing the TIN data before working on the above steps. I'm back at WMS again and will try to report back exactly what the issue was. Thanks, Dave
  7. Hi Chris, Thanks for your reply. One of the reasons I'm interested in WMS is because I do not always have access to an ArcView license or personnel to work in ArcView. Having a front end with some GIS capability is a selling point for this software. But it definitely needs some control on colors for reporting purposes. Is there any way to reset the algorithm so it chooses new colors or edit a file manually or get around the problem within WMS? Best, Dave
  8. I've just had WMS assign the same color to 2 basins which are side by side. They are no longer distinguishable when filled. Is there any way to control the color fills on objects in WMS. Thanks, Dave
  9. Hi, I have a bug that may have been introduced when either -following the tutorial "Volume2, sections 2.2.6 and 2.2.7" in order to add stream arcs, define basins, and compute basin data. -Or more likely, changing the autocad information in the file. Essentially swapping out an old bloated file with a new file containing additional information I need. The new information is significantly smaller in size (3mb vs. 25mb). Essentially the load times have increased exponentially. Where I used to get about 20 second load times, I am now looking at 5 minute load times unless it freezes. The loading stage it is stuck on is "updating the drainage units to feature polygons". It stalls at 75%. I am using the tutorials on my own watershed data (based of autocad contours). If this is not a known bug and the info above is a little light, I may be able to provide additional info. Thanks, Dave P.S., as I type this, another file is stuck on "Deleting trianges 0%" but just finished loading at about 5 minutes. However, I am now looking at a grey screen with only a basin id showing (and its associated information like basin are and slope). The program is frozen at this point.
  • Create New...