I have 102 .tif files to merge. I want to use the raster calculator on these, but it said there was not enough memory when I tried using the raster calculator on the virtual raster of all 102 files. When I try raster -> misc -> merge, there is an error message saying:

Error 5: Pixel type must be float32


Any recommendations?

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  • 1
    Did you check the pixel type of your rasters?
    – Techie_Gus
    Apr 2, 2018 at 6:04

1 Answer 1


You need to use the Merge tool from Processing toolbox -> GDAL/OGR -> Miscellaneous -> Merge because it gives you the option to specify the pixel type of Float32.

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The Merge tool accessed from Raster -> Miscellaneous -> Merge does not have show pixel type option or it is hidden and you may need to specify it explicitly using the creation option, but I didn't try it.

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  • That worked for me Ahmadhanb. Thank you. I still get the error message "Raster calculator: insufficient memory available for the operation." I have been able to do large raster calculations before without a problem, so I am wondering if it has something to do with the raster being merged.
    – mmmm
    Apr 3, 2018 at 0:57
  • @Ross It looks like that the raster file size is too big. Usually Float32 pixel type raster images have big file sizes, so when you merged the raster images together it becomes very big that the raster calculator finds it difficult to process.
    – ahmadhanb
    Apr 3, 2018 at 5:18
  • OK, thanks. I will post a new question about this.
    – mmmm
    Apr 4, 2018 at 22:43

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