# Does normal mapping make sense for a view of earth from space?

I am working on a planet visualizer, which at this point is little more than the NASA blue marble image applied as a diffuse texture. For the atmospheric rim, I am simply blending in a constant color depending on Fresnel. It looks like this:

Besides the obvious problems (no clouds) I am struggling to understand what techniques are applicable at this scale. As I understand it, normal mapping is simply a modeling of surface features below the threshold of polygon resolution. Likewise, roughness-based BRDFs are simply a modeling of surface features below the threshold of normal maps. In my case, I am using the 8k texture map at 500m resolution. Does it make sense to normal map the Earth from this distance? How would I even do that? Is there a height map for the planet?

Are there other techniques that are more applicable to rendering (real) planets like this? My next step is to make a specular mask based on water cover, but I feel like I am missing something else.

P.S. I noticed that the NASA blue marble image didn't render well when I enabled gamma correction, nor when I divided its texel values by $\pi$ before computing the light value. I'm not sure why that is.

• I've guessed that the capitalised "PI" was referring to the constant $\pi$ as I couldn't think of an acronym that would fit. If this is not your intention please edit to correct. Apr 4, 2017 at 21:00