Hec Geo Ras - River Node Lies Outisde the Terrain

Discussion created by buffalodan on Dec 21, 2011
Latest reply on Apr 15, 2016 by davidc.gunawan
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.