[interpolation] Add NN(s) method

AbelVM commented 8 years ago

[x] All declared geometries are geometry(Geometry, 4326) for general geoms, or geometry(Point, 4326)
[x] Existing functions in crankshaft python library called from the extension are kept at least from version N to version N+1 (to avoid breakage during upgrades).
[x] Docs for public-facing functions are written
[x] New functions follow the naming conventions: CDB_NameOfFunction. Where internal functions begin with an underscore _.
[x] If appropriate, new functions accepts an arbitrary query as an input (see Crankshaft Issue #6 for more information)

iriberri commented 8 years ago

It looks good, I just noticed that the output value -777.777 is not documented though. Not sure if you'd want to raise an exception if the method selected is 3.

Also, it's not new code, but I wonder why you initialize output to -999.999 if that value is never used.

AbelVM commented 8 years ago

Yes to all :smile: I'm gonna check those little leftovers

AbelVM commented 8 years ago

:clap: :clap:

CartoDB / crankshaft

[interpolation] Add NN(s) method #129