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cd7d1c9183
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 a `geo_point` field, as well
as 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.
```
{
"query": {
"bool": {
"must": [
{ "term": { "person": "004" } },
{ "term": { "trajectory": "20090131002206.plt" } }
]
}
},
"aggs": {
"make_line": {
"geo_line": {
"point": {"field": "location"},
"sort": { "field": "timestamp" },
"include_sort": true,
"sort_order": "desc",
"size": 15
}
}
}
}
```
```
{
"took": 21,
"timed_out": false,
"_shards": {...},
"hits": {...},
"aggregations": {
"make_line": {
"type": "LineString",
"coordinates": [
[
121.52926194481552,
38.92878997139633
],
[
121.52922699227929,
38.92876998055726
],
]
}
}
}
```
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
closes #41649
143 lines
2.9 KiB
Text
143 lines
2.9 KiB
Text
[role="xpack"]
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[testenv="gold"]
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[[search-aggregations-metrics-geo-line]]
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=== Geo-Line Aggregation
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++++
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<titleabbrev>Geo-Line</titleabbrev>
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++++
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The `geo_line` aggregation aggregates all `geo_point` values within a bucket into a LineString ordered
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by the chosen `sort` field. This `sort` can be a date field, for example. The bucket returned is a valid
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https://tools.ietf.org/html/rfc7946#section-3.2[GeoJSON Feature] representing the line geometry.
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[source,console,id=search-aggregations-metrics-geo-line-simple]
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----
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PUT test
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{
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"mappings": {
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"dynamic": "strict",
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"_source": {
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"enabled": false
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},
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"properties": {
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"my_location": {
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"type": "geo_point"
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},
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"group": {
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"type": "keyword"
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},
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"@timestamp": {
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"type": "date"
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}
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}
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}
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}
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POST /test/_bulk?refresh
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{"index": {}}
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{"my_location": {"lat":37.3450570, "lon": -122.0499820}, "@timestamp": "2013-09-06T16:00:36"}
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{"index": {}}
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{"my_location": {"lat": 37.3451320, "lon": -122.0499820}, "@timestamp": "2013-09-06T16:00:37Z"}
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{"index": {}}
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{"my_location": {"lat": 37.349283, "lon": -122.0505010}, "@timestamp": "2013-09-06T16:00:37Z"}
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POST /test/_search?filter_path=aggregations
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{
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"aggs": {
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"line": {
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"geo_line": {
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"point": {"field": "my_location"},
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"sort": {"field": "@timestamp"}
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}
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}
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}
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}
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----
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Which returns:
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[source,js]
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----
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{
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"aggregations": {
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"line": {
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"type" : "Feature",
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"geometry" : {
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"type" : "LineString",
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"coordinates" : [
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[
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-122.049982,
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37.345057
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],
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[
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-122.050501,
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37.349283
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],
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[
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-122.049982,
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37.345132
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]
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]
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},
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"properties" : {
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"complete" : true
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}
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}
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}
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}
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----
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// TESTRESPONSE
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[[search-aggregations-metrics-geo-line-options]]
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==== Options
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`point`::
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(Required)
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This option specifies the name of the `geo_point` field
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Example usage configuring `my_location` as the point field:
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[source,js]
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----
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"point": {
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"field": "my_location"
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}
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----
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// NOTCONSOLE
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`sort`::
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(Required)
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This option specifies the name of the numeric field to use as the sort key
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for ordering the points
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Example usage configuring `@timestamp` as the sort key:
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[source,js]
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----
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"point": {
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"field": "@timestamp"
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}
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----
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// NOTCONSOLE
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`include_sort`::
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(Optional, boolean, default: `false`)
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This option includes, when true, an additional array of the sort values in the
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feature properties.
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`sort_order`::
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(Optional, string, default: `"ASC"`)
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This option accepts one of two values: "ASC", "DESC".
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The line is sorted in ascending order by the sort key when set to "ASC", and in descending
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with "DESC".
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`size`::
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(Optional, integer, default: `10000`)
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The maximum length of the line represented in the aggregation. Valid sizes are
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between one and 10000.
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