Algorithm 5.

SparkGIS Spatial kNN

1:	procedure NativeSpatialKNN(tile, k, searchRadius)
2:	dataset1 // all objects from dataset1 in tile
3:	dataset2 // all objects from dataset2 in tile
4:	/* local R*tree index */
5:	localIndex.build(dataset2)
6:	getObjectDensity()
7:	for each object in dataset1 do
8:	while searchRadius < spacedimensions do
9:	/* Use local index to get qualifying objects */
10:	if qualifying objects > (k * 1.5) then
11:	break
12:	else searchRadius* = 2
13:	end if
14:	end while
15:	end for
16:	for each qualifying object from dataset2 do
17:	Compute distance
18:	end for
19:	Sort(distance, neighbors)
20:	return first k results
21:	end procedure