104 lines
2.5 KiB
Plaintext
104 lines
2.5 KiB
Plaintext
[[search-aggregations-metrics-geocentroid-aggregation]]
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=== Geo Centroid Aggregation
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A metric aggregation that computes the weighted centroid from all coordinate values for a <<geo-point>> field.
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Example:
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[source,js]
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--------------------------------------------------
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{
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"query" : {
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"match" : { "crime" : "burglary" }
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},
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"aggs" : {
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"centroid" : {
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"geo_centroid" : {
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"field" : "location" <1>
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}
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}
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}
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}
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--------------------------------------------------
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<1> The `geo_centroid` aggregation specifies the field to use for computing the centroid. (NOTE: field must be a <<geo-point>> type)
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The above aggregation demonstrates how one would compute the centroid of the location field for all documents with a crime type of burglary
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The response for the above aggregation:
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[source,js]
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--------------------------------------------------
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{
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...
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"aggregations": {
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"centroid": {
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"location": {
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"lat": 80.45,
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"lon": -160.22
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}
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}
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}
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}
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--------------------------------------------------
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The `geo_centroid` aggregation is more interesting when combined as a sub-aggregation to other bucket aggregations.
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Example:
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[source,js]
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--------------------------------------------------
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{
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"query" : {
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"match" : { "crime" : "burglary" }
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},
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"aggs" : {
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"towns" : {
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"terms" : { "field" : "town" },
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"aggs" : {
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"centroid" : {
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"geo_centroid" : { "field" : "location" }
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}
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}
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}
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}
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}
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--------------------------------------------------
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The above example uses `geo_centroid` as a sub-aggregation to a <<search-aggregations-bucket-terms-aggregation, terms>> bucket aggregation
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for finding the central location for all crimes of type burglary in each town.
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The response for the above aggregation:
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[source,js]
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--------------------------------------------------
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{
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...
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"buckets": [
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{
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"key": "Los Altos",
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"doc_count": 113,
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"centroid": {
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"location": {
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"lat": 37.3924582824111,
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"lon": -122.12104808539152
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}
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}
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},
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{
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"key": "Mountain View",
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"doc_count": 92,
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"centroid": {
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"location": {
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"lat": 37.382152481004596,
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"lon": -122.08116559311748
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}
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}
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}
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]
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}
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-------------------------------------------------- |