Sampling the splatmap with raycasts

It seems like it should be possible to get a pixel from a terrain’s splatmap corresponding to where a raycast hit in 3D, but I can’t find a one-step way to do it and I don’t see the tools to do it by hand either. TerrainData is the obvious place to look, but I only see ways to get at height data.
In case it matters, let’s assume that the splatmap and the hieghtmap are the same dimensions.

Any ideas?

Can’t you just pull the pixel from the corresponding position in an array? Where you want to look, btw, is terrainData.AlphaMap