I suppose really I'm showing my DSP-training by saying that a Fourier is from a time domain, really it's just a special mapping between two domains, and it just

I suppose really I'm showing my DSP-training by saying that a Fourier is from a time domain, really it's just a special mapping between two domains, and it just so happens that it correlates with the physical analogues of time domain -> time frequency, space domain -> spatial frequency. In this case it's really space domain -> spatial frequency, but w/e