HEC-RAS User's Manual HEC-RAS Data Exchange Current: RAS GIS Import File (RASImport.sdf) PDF Download PDF Download page RAS GIS Import File (RASImport.sdf). Current page Include child pages All pages RAS GIS Import File (RASImport.sdf) HEC-RAS reads channel geometry from a text file composed of several sections. A discussion of the sections in the import file is provided. And example RAS GIS import File is provided at the end of this appendix. ×