[geokon]

Not my area of expertise, but in my limited experience DEM tiles are usually GeoTIFF. This can be 16bit greyscale. The catch is that these are actually signed... Elevation doesn't start at 0meters bc you have locations below sea level and you need to handle those corner cases somehow

What's funny is that you can parse a GeoTIFF as a .tiff most of the time but not always. I had fun debugging that :). Java's BufferedImage understandably doesn't directly support negative pixel values haha

[berkut]

Data from sources like GMTED2010 or SRTM15+ is often float32 or even float64: whether it needs to be is another question, but float16 often isn't sufficient in terms of magnitude accuracy (IEEE), and as you mention you often need negative values as well, which for the whole ocean surface of the earth, more than double the range.

To me (working in the VFX industry with EXR being the predominant HDR format), it's interesting that something that compresses a lot better than TIFF (i.e. EXR) hasn't won over in the GIS space, but I believe that's mostly momentum as well as the fact EXR doesn't natively support 64-bit float, but then neither does TIFF really (it's an extension), and the same could be done with EXR (extend the formats it supports).