Export elevations as feet instead of meters?

0 votes
65 views
asked Jul 13 by Loren Amelang
USGS NED DEMs all present elevation in meters. This appears to cause problems in HEC-RAS when the rest of your project is in feet. It looks like all of the (expensive) alternatives to RiverGIS have an option for converting to feet as part of the creation of an export file. I'm not finding this in RiverGIS.

You can work around the issue (once you realize it exists) by using:
HEC_RAS -> Edit -> Geometric Data Editor -> Htab Param. -> (select) -> Multiply Factor ...
Select "All Rivers", select the elevation column by clicking its label, and multiply by a factor of 3.280833.

But since RiverGIS claims to make a file ready for import to HEC-RAS, maybe it could handle this task as well? As an option of course, in case someone really does have all the rest of their elevation data in meters...

1 Answer

0 votes
answered Sep 26 by anonymous
Adjust your DEM in qgis using raster calculator for unit conversions and vertical datum shifts. That's standard practice with any model development.
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