exportqgisqgis-2raster
Could someone explain how to export a 16-bit image from QGIS ?
I have imported data and coloured it as I want, but need to export it as a 16-bit image, as 8-bit is giving a terracing effect. I believe, I need to use this code in OSGeo4W Shell, but I don't know how to use it.
gdal_translate -ot Int16 -srcwin xoff yoff xsize ysize -outsize xsize ysize src_dataset dst_dataset
Here is a screenshot of my map, which has the following extent:
Xmin 510000, Ymin 156000, Xmax 528000, Ymax 174000
In QGIS, Raster -> projections -> warp calling GDAL's gdalwarp utility is the method to change the CRS of a raster file.
This is an external command, so it does not look at the project or layer CRS you might have set in QGIS.
Select the right CRS for source, and the desired for target CRS, abd give the output a different filename. You can add the result to the canvas, and check the extent in the layers properties, metadata tab. It should be different from the originals extent
At the start of your question you ask about going from 32 bit to 8 bit and at the end you ask about going the other way, so this will be a generic answer.
Most of the GDAL functions allow you to specify the pixel depth with the commandline tag -ot (for instance see the documentation on gdal_translate or gdal_rasterize). The -ot switch can take the values Byte/Int16/UInt16/UInt32/Int32/Float32/Float64/ CInt16/CInt32/CFloat32/CFloat64.
In QGIS, if you want to force the output from a GDAL function to give you a specific pixel depth rather than a default, then edit the commandline to include the -ot switch with whatever pixel depth you want. For instance go Raster->Conversion->Translate. At the bottom of the dialog box (at least in version 1.9) you will see the commandline command generated for you. Click the button next to it with little pencil icon to allow you to edit the commandline and add your -ot switch.
Example using gdal_translate in QGIS, converting from floating point 32 bit to 16 bit unsigned integer:
Best Answer
In QGIS 3+ one can issue the command directly from the interface:
Raster->Conversion->Translate (Convert Format)and select
Int16inOutput Data Type:The output file is a 16 bit one: