Algorithm for finding nearby points?

Question

Given a set of several million points with x,y coordinates, what is the algorithm of choice for quickly finding the top 1000 nearest points from a location? \"Quickly\" here mea

Answer 1

i know its been said as not being the fastest if you want REALLY REALLY fast results by seeing i found this post from google i thought i'd add my SQL solution that i used a while ago in the form of a stored proc. It looks for locations close by the a coord and returns them by distance.

I hope it helps someone :)

CREATE PROCEDURE [dbo].[getstores] @lat float,  @lng float AS
DECLARE @radius float, @DegToRad float
SET @DegToRad = 57.29577951
SET @radius = 25000
SELECT TOP 10
    name
    ,sto_lat
    ,sto_lng
    ,postcode
    ,ROUND((ACOS((SIN(@lat/57.2958) * SIN(sto_lat/@DegToRad)) +(COS(@lat/@DegToRad) * COS(sto_lat/@DegToRad) *COS(sto_lng/@DegToRad - @lng/@DegToRad))))* 6387.7, 2) AS distance
FROM store
WHERE (sto_lat >= @lat - (@radius/111))
And (sto_lat <= @lat + (@radius/111))
AND (sto_lng >= @lng - (@radius/111))
AND (sto_lng <= @lng + (@radius/111))
AND (
     ISNUMERIC(sto_lat) = 1
    AND
    ISNUMERIC(sto_lat) = 1
)
ORDER BY distance

NOTE: i have already stated that this is not the best solution for this question simply maybe for someone who found this on google like me