Algorithm in disk query?

[cdeil]

@michitaro - Is the algorithm you use for disk query described somewhere?
(a webpage or paper?)

If no, could you please add a few comments to the docstring to make it easier to understand what it does?

healpix/src/index.ts

Line 135 in 99f2305

export function query_disc_inclusive_nest(nside: number, v: V3, radius: number, cb: (ipix: number) => void) {

[cdeil]

I've found a description of the HEALPix query algorithm used in the C++ implementation:
See Section 7 in http://adsabs.harvard.edu/abs/2015A&A...580A.132R

I still have to review and understand the call-back based implementation here by @michitaro and the algorithm by @dstndstn in here.

@michitaro @dstndstn - Can you comment on how your implementation compares to the one proposed there, and which one you think we should use (here in the Typescript and there in the C implementation)?