I am looking to convert a .DEM exported from AutoCad to a floating point raster file type (.FLT) utilizing QGIS to implement in HEC-RAS Mapper.
This is accomplished easily in Arc using the Raster>Float option. Referencing ESRI Supported Formats it does not appear the .FLT format is proprietary. It does mention "Write—Only via Raster To Float tool, or developer code" which could suggest that it could be incorporated into QGIS. Although, the QGIS Raster>Translate does not offer the .FLT format.
Is there open-source workaround to convering DEM to .FLT?
Best Answer
The Esri FLT data format stores its data identically to an Esri BIL file, which GDAL does support:
Then all you need to do is change the extension from bil to flt and edit the header - the keywords are different.. for example:
is what is in the header from GDAL translate, which needs to be changed to:
for a FLT file... easy as!
First change NODATA to NODATA_VALUE (if not already, both keywords are supported by Esri BIL),
BYTEORDER
keyword changes fromI
(Intel) toLSBFIRST
- assuming Intel, only one cellsize is supported so get rid ofXDIM, YDIM
and replace withCELLSIZE
changeULXMAP
toXLLCENTER
and then it gets tricky.. BIL is upper left referenced but FLT is lower left referenced so you need to reduce the reference byNROWS * CELLSIZE
to obtainYLLCENTER
.You should be able to validate your results in QGIS (I used 2.6 (Brighton)) by drag-n-drop the .flt file into the window.