Hec Geo Ras - River Node Lies Outisde the Terrain

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12-21-2011 03:56 PM
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DanielAshbaugh
New Contributor
I am just now starting to play with ArcGis, and using it for doing inundation mapping. I am following the instructions in the hand book, however am encountering an error after drawing a center line. It tells me to go to RAS Geometry - > Attributes - > Topology. But when I do that, it tells me "River Node Lies Outside Terrain"  I am not sure what it is. I have brought in a NED from the USGS Seamless server and it appears that it is in a grid format and has elevations associated with it. The steam is just a simple line. I erased the real one and tried it with two points and am getting the same error. I even started from scratch and got the same thing. 

This is my first project in ArcGIS, and our offices. I have run the examples without problems but would appreciate any help.

Thanks
-Dan
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8 Replies
MattMead
New Contributor III
That error means that the line you are trying to process has at least 1 vertex outside the limits of your terrain data.  If it looks like your centerline is within the terrain data limits check spatial references to see if they are the same. (right click on your files in the Table of Contents->properties->Source tab)  If I remember correctly, even though ArcGIS reprojects data on the fly to allow everything to show up correctly I dont believe GeoRAS does the same when its processing. 

Failing that, I've never worked with GeoRAS using a DEM(grid) before, I have always used TINS.  You could try converting your grid to a TIN but keep in mind there will probably be errors introduced in the process.  I'm not at my work machine so I cant tell you exactly where the convert raster to TIN is....Its in either Spatial Analyst or 3dAnalyst.  Only time I've ever had the "node outside terrain" error with a TIN is when I actually had portions of my centerline outside the TIN. 

If that doesnt work, I'm not entirely sure if GeoRAS will cooperate with a server based terrain file. I know we have had issues in 9.3.1 with a couple server shapefiles not processing correctly, but I dont know if that is a server issue or an Arc limitation You could create a clipping polygon and under Spatial Analyst is "Extract by Mask" which will allow you to clip your grid with whatever polygon shapefile you want.  This will create a copy of the grid where ever you want to save it.

Good luck. (also, post if you are using arc 10 or an older version as the version of GeoRAS are different)
Genianull
New Contributor

Your comment is still useful in 2021, thanks!

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DanielAshbaugh
New Contributor
It is arc10. I am going to run through the examples again this week and play around with it some more. Maybe tackle this specific problem next year. It was able to convert to a tin, but still had the same issues. I didn't get the extract by mask to work, but there was quite a bit that was new to me. Hopefully after a week of playing it will come together.

[Edit 1]
Playing around with it tonight. I opened up an example, and then brought in my items. Any line drawn on my raster/tin/dem gives an error, any line drawn on the example does not. So I am thinking I have made a bad terrain file then. I brought mine in from the streamless server as the usgs.
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DanielAshbaugh
New Contributor
I figured it out. Not sure what I was doing wrong, but I made a contour out of my data, then created a tin from that. That surface is working beautifully. I am sure I will be asking more questions, but have successfully ran a pretty simple simulation ( 3 cross sections and steady flow).

Thanks.
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ShelbySmith
New Contributor
Hello,

I did a Google search on this issue because I am encountering the same problem. It's been holding me up for a couple days now. I am working on a river reach that supposedly has a node outside the terrain. I've been following the examples step by step and it doesn't fix the issue. I have converted the GRID to a TIN

Can you describe the contour process that you followed which solved the problem? I saw in the Example Application (Chapter 😎 from the Users Manual you can create contours from a DTM. Is that the methodology you used?

Any help greatly appreciated.
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by Anonymous User
Not applicable
Thanks for the tips! It was a coordinate system issue for me.  My vector stream data was in one coordinate system, while my surface was in another.  As Meadmw pointed out, since ArcMap projects on the fly I never noticed that they differed since they still lined up fine. Changed the coordinate systems to match and all is well.
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johngartner
New Contributor
Yes- coordinate issue for me too. I extracted the area of interest from my DEM (using "Extract by mask") and set the output coordinates (under the environments button at the bottom of the tool dialog box) to match the coordinate system of my hec-georas layers, e.g. the layer "river."

Then changed the terrain to my new DEM that I made from extract by mask.

It worked fine after this.
davidgunawan2
New Contributor

I follow this discussion and also find the same problems when to use .flt format. Ialso notice shape_length in gdb show small number (in 1:20000 scale) which is not correct. This is another problem? any info would be great

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