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I would like to create a flt (floating point raster) with QGIS to use later as a terrain in Hec RAS RAS-Mapper. With Raster -> Conversion -> Translate there is no option to create a flt. Is there another way?

2 Answers 2

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Save your raster as ESRI .hdr with datatype as float32 and file extension as ".flt".

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  • Tank you Luke, that was what i was searching for. It s working now.
    – Isi
    Dec 11, 2015 at 11:55
  • "BIL" is "Band Interleaved by Line" per desktop.arcgis.com/en/arcmap/latest/manage-data/… It could be important if you want to store multi-band rasters in a .flt file. Maybe concatenate 3 .flt files together sequentially and edit a .hdr file to set the layout to "BSQ"
    – Dave X
    Nov 14, 2023 at 14:32
  • Is there a way to do this in an automated manner?
    – i.i.k.
    Feb 19 at 14:56
  • @i.i.k. yes. As the QGIS Raster -> Conversion -> Translate tool uses GDAL internally to convert, you could cut out the middle man and use the gdal_translate commandline tool with a batch/shell script or in python with the osgeo.gdal.Translate method. Note: comments aren't for questions, so if you get stuck ask a new question.
    – user2856
    Feb 19 at 20:55
  • @user2856 You are right, I should open a new question. Unfortunately the installation of gdal with the pip-packagemanager failed.
    – i.i.k.
    Feb 20 at 9:45
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To output an raster with data type integer as of type float use the raster calculator.

  1. execute the trivial expression "raster@band_no" * 1.0 (replace raster@band_no with an appropriate value or simply double click the entry in the raster channel list)
  2. save the output in a format, that supports floating point values, eg GeoTIFF
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  • Thank you for your help. But it is still not what i'm searching for. With the raster calculator I can get the same data typ like raster -> Conversion -> Translate. Like you sad, I can save as an GeoTIFF (*.tif) but I need it as *.flt. I have no possibility to upload a GeoTIFF in Hec RAS - RAS Mapper.
    – Isi
    Dec 11, 2015 at 7:28

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