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I'm a 3D artist working on a procedural planet generator, based on colour and height textures from real-life areas. I've been using the GeoTIFF files from NASA Visible Earth, but they all seem to be in 8 bit format which causes bad stepping artifacts when they're used as height maps.

Is there anywhere I can find global 16 bit height rasters, or is it possible for me to increase the bit depth of the ones from NASA Visible Earth?

Or are there any non-raster elevation datasets that I can convert into 16 bit rasters with QGIS? I suspect this would be the best method, but I don't know QGIS very well, so I have no idea how.

screenshot from Substance Designer showing stepping artifacts on desert terrain

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You are probably looking for the Translate tool in QGIS. There, select UInt16 as the output format and you should be fine.

However, in order to avoid the terracing you shared on your OP, you need to Rescale your GeoTIFF first: in order to do so, you have to stretch your elevation between 0 and 65,535, as that's the pixel range 16-bit TIFFs can hold.

In this case, let's imagine your elevation goes from 100 to 378 m. Using the Calculator in QGIS, what we are going to do is to make 100 become 0 and 378 become 65,535.

Thus, the formula you need is the following one:

(File Name – Lowest Value) ÷ (Highest Value – Lowest Value) * 65,535

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    This doesn't eliminate difference between 2 distinct value on neighboring terraces.
    – FelixIP
    Commented Dec 7, 2022 at 22:27
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    True. For that, what I do is combine different smoothed/blurred versions of the resulting tiff in Photoshop/Gimp. See the following tutorial for instance somethingaboutmaps.wordpress.com/2022/01/13/…
    – Kasper
    Commented Dec 8, 2022 at 7:26
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For further information on this issue, you can always read this famous article by Daniel Huffman. More specifically, regarding your issue, you can check steps from 6 to 8:

Daniel Huffman´s tutorial

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    Commented Dec 8, 2022 at 9:34

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