[GIS] DTM data type from Int16 to Float

demearth-explorerqgis

I downloaded a data set 'SRTM Arc-Second Global' from the USGS EarthExplorer (GeoTIFF 1 Arc-second). Apparently, the DTM data type is Int16 whereas I need Float. I am trying to convert the format using the Raster -> Conversion -> Translate (Convert Format) … dialogue in QGIS. However, if I run e.g.

gdal_translate -of GTiff
-ot Float32
-co COMPRESS=LZW (lossless compression)
 /Downloads/Tra_Vinh_.tif
 /Downloads/Tra_Vinh_float.tif

I receive the following error:

ERROR 6: Too many command options '/Downloads/Tra_Vinh_.tif'

If I use less command options, e.g.

-ot Float32
-co COMPRESS=LZW (lossless compression)
/Downloads/Tra_Vinh_.tif
/Downloads/Tra_Vinh_float.tif

or

-ot Float32
/Downloads/Tra_Vinh_.tif
/Downloads/Tra_Vinh_float.tif

It says:

The process failed to start. Either the invoked program is missing, or
you may have insufficient permissions to invoke the program.

Best Answer

qgis uses gdal for raster conversion. if you use the raster > conversion > convert tool in QGIS, you will have a command line that fills automatically at the bottom of the form. Simply use the edit button to add

-ot Float32

on the command line and run the tool. Note that you can add other usefull option, such as:

-co COMPRESS=LZW (lossless compression)

-co TILED=yes (tiling)
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