Episode 27: Hidden Secrets of RAS Mapper

[@BethanyHackenjos]

I've been using RAS for 10 years now. Heard about full momentum over the years through web searches trying to figure out issues and how to do thing in RAS. I'm a river restoration and fish passage engineer. Still always learning.

[@ryantroy7171]

Good episode - welcome bank! I've been using HEC-RAS for ~15 years so an older follower of the blogspot. I'm more of a senior engineer now, so do more model review and report writing... I use the "Views" window a lot. Set an extent of interest for multiple maps, develop inset type maps, and inundation map extents. Works well if I just need a few screenshots/preliminary results instead of using a GIS platform. I use the "Layer Values" window a lot too. Set 3-4 different things of interest (terrain, depths of 2-3 different plans, courant numbers) so I can look at multiple things when I hover. For the bridge episode, can you go over the "internal boundary rating curves". I would like to have some reference to point junior engineers to on that topic. With 2D bridges, I have found that it is best to limit the length of the bridge to only the immediate opening (unlike in 1D models).

[@GaryLemay-py9uc]

Great episode! If you ever do a follow up in the future another favorite of mine is the “Update Elevations by Points” tool that lets you pull a shape file of survey data in to update your XS elevations without having to match the points to stationing yourself. Makes it really easy to take a few cross-sections of survey and burn a channel into the terrain, as you have explained in previous episodes!

[@panicellu]

You guys are always providing useful tips! Thank you and greetings from Italy

[@helderguta2303]

Thats really nice that you guys are back :D

[@lumartinsgeo]

Nice video. Ras mapper had a lot of improvements. I work everyday with it, one of the things that I think would be possible to do is create gaps inside the mesh area (donut polygons) it would help a lot reducing the number of cells in complex models Great job guys 🎉

[@IanaMoto]

Hi, for complex and large models it might be useful to use refinment regions. This might give you flexibility on mesh dimensions depending on the areas you want to focus most, therefore helps reducing number of cells. Hope this helps

[@civilenggggg]

Donuts holes are not allowed in RAS. This includes importing mannings override region polygons from FEMA data with donut holes. You can however use "no data regions" to ignore sections of your mesh

[@lumartinsgeo]

Yes but in some cases having a high range of mesh cell sizes can originate a lot of instability errors​@@IanaMoto

[@lumartinsgeo]

​@@civilenggggghow can we create them?

[@civilenggggg]

@@lumartinsgeo In RAS Mapper, terrain modifications>polygons>autofill no data regions

[@IanaMoto]

Hello, great Ras Mapper review, can't wait for the next session on Raster calculator. If any questions are taken into account for next session than, here is one: is there any chance it is possible to use raster calculator to calculate at what timestep maximum flow reaches specific "cross sections" in a 2D model? Thank you, greetings from Romania

[@tanguyroussin4033]

Hello, I am facing a difficulty that I cannot overcome with RAS Mapper. When displaying the results of a 2D simulation, I am looking for a way to display in each of the cells of the mesh only the value corresponding to the calculation point of the cell (a constante value for all the cell). I want to see only the calculated value and not projected on the terrain or interpolated between cells. Is there anyone who knows how to do this? Thanks in advance

[@stevenseville6208]

Intro music really sets the tone

[@dhruvvaidhya8866]

Hellow , I have question on hec ras , I'm trying to generate 1D model but in geometry I can't change Mannings N value , it shows -9999 Please tell me what should I do ?

[@saatviksatyaprakash4421]

You possibly don't have the bank stations set for that particular XS.