[backport] Add geo_line aggregation (#41612) #65442
Merged
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A metric aggregation that aggregates a set of points as
a GeoJSON LineString ordered by some sort parameter.
A
geo_line
aggregation request would specify ageo_point
field, as wellas a
sort
field.geo_point
represents the values used in the LineString,while the
sort
values will be used as the total ordering of the points.the
sort
field would support any numeric field, including date.Due to the cardinality of points, an initial max of 10k points
will be used. This should support many use-cases.
One solution to overcome this limitation is to keep a PriorityQueue of
points, and simplifying the line once it hits this max. If simplifying
makes sense, it may be a nice option, in general. The ability to use a parameter
to specify how aggressive one wants to simplify. This parameter could be
the number of points. Example algorithm one could use with a PriorityQueue:
https://bost.ocks.org/mike/simplify/. This would still require O(m) space, where m
is the number of points returned. And would also require heapifying triangles
sorted by their areas, which would be O(log(m)) operations. Since sorting is done,
anyways, simplifying would still be a O(n log(m)) operation, where n is the total number
of points to filter........... something to explore
backport of #41612