Hey!

I've been tinkering around with trying to reduce file size of height & elevation data, and was wondering about the value (or not) of adding support for float16 in rasterio.

Reasoning for this:

• Most height rasters are in meters. This means that realistically, on Earth, values will be between, taking at max: 9000 (Everest) and -13000 if we go underwater, to Marianna trench.
• For most applications, the accuracy of any measurements would be pushing it to go beyond millimetres, i.e. 10^-3

This looks like float16 would be a dtype data fit for this type of raster. Benefits being able to store the same amount of information practically speaking as a float32 raster, but for a much smaller file.

I was surprised to see float16 not being implemented in rasterio actually, so am I missing something here? I also haven't found previous discussion about this hence why I'm opening this post

Genuinely curious!