The RAS mapper is more trouble than its worth most of the time. It is much easier to do without it as debugging can be time consuming. 1)create a copy of your georas cross sections(not 100% necessary, but its always bad to play around with your finished model files) right click on the cross section file->Data->export data. 2)add field to the new cross section file attribute table for each RAS profile you want to map(the default "double" settings work just fine) 3) in an edit session,copy in your RAS output if you have bridges you may need to copy the output to Excel or other database program first to remove the extra lines 4)In 3dAnalyst toolbar, Create/Modify Tin->Create Tin from features Select your new cross section file and set it to the appropriate profile for the height data source 5)In 3dAnalyst toolbox->TIN Surface->Tin Difference This will create a polygon of your floodplain with 3 values. Above, below and same. Delete the below as this is outside your floodplain. Doing it this way allows you to have more control over the initial floodplain. The RAS mapper only works with whatever was originally in the model instead of what would make sense for mapping. A model cross section wont extend into backwater areas, or other areas where a linear interpolation from model cross sections would incorrectly map flood elevations. This process allows you to modify the mapping cross sections however you want(which is another reason to export them an not use the georas files). I'm having the same problem. I don't mind which way to use, I just want to delineate the floodplains. But I didn't understand everything you said. Is it that I need to export the results from hecras and once I have it in ArcMap, export the shape containing the cross sections? And then? Could you please explain me a little bit more!!! Thanks in advance
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