地理距离聚合 geo_distance

Geo Distance Aggregation

在geo_point字段上工作的多桶聚合，在概念上与范围聚合非常相似。用户可以定义源点和一组距离范围桶。聚合评估每个文档值与原点的距离，并根据范围确定其所属的桶（如果文档与原点之间的距离在桶的距离范围内，则文档属于该桶）。

PUT /museums
{
    "mappings": {
        "_doc": {
            "properties": {
                "location": {
                    "type": "geo_point"
                }
            }
        }
    }
}

POST /museums/_doc/_bulk?refresh
{"index":{"_id":1}}
{"location": "52.374081,4.912350", "name": "NEMO Science Museum"}
{"index":{"_id":2}}
{"location": "52.369219,4.901618", "name": "Museum Het Rembrandthuis"}
{"index":{"_id":3}}
{"location": "52.371667,4.914722", "name": "Nederlands Scheepvaartmuseum"}
{"index":{"_id":4}}
{"location": "51.222900,4.405200", "name": "Letterenhuis"}
{"index":{"_id":5}}
{"location": "48.861111,2.336389", "name": "Musée du Louvre"}
{"index":{"_id":6}}
{"location": "48.860000,2.327000", "name": "Musée d'Orsay"}

POST /museums/_search?size=0
{
    "aggs" : {
        "rings_around_amsterdam" : {
            "geo_distance" : {
                "field" : "location",
                "origin" : "52.3760, 4.894",
                "ranges" : [
                    { "to" : 100000 },
                    { "from" : 100000, "to" : 300000 },
                    { "from" : 300000 }
                ]
            }
        }
    }
}

返回

{
    ...
    "aggregations": {
        "rings_around_amsterdam" : {
            "buckets": [
                {
                    "key": "*-100000.0",
                    "from": 0.0,
                    "to": 100000.0,
                    "doc_count": 3
                },
                {
                    "key": "100000.0-300000.0",
                    "from": 100000.0,
                    "to": 300000.0,
                    "doc_count": 1
                },
                {
                    "key": "300000.0-*",
                    "from": 300000.0,
                    "doc_count": 2
                }
            ]
        }
    }
}

field 必须是geo_point类型，也可以为一组geo_point字段。

origin 可以接受geo_point类型支持的所有格式：

• 对象格式：｛“lat”：52.3760，“lon”：4.894｝-这是最安全的格式，因为它是最明确的lat和lon值
• 字符串格式：“52.3760，4.894”-其中第一个数字是lat，第二个数字是lon
• 数组格式：[4.894，52.3760]-基于GeoJson标准，其中第一个数字是lon，第二个数字是lat

默认情况下，距离单位为m（米），但也可以接受：mi（英里）、in（英寸）、yd（码）、km（公里）、cm（厘米）、mm（毫米）。

POST /museums/_search?size=0
{
    "aggs" : {
        "rings" : {
            "geo_distance" : {
                "field" : "location",
                "origin" : "52.3760, 4.894",
                "unit" : "km", 
                "ranges" : [
                    { "to" : 100 },
                    { "from" : 100, "to" : 300 },
                    { "from" : 300 }
                ]
            }
        }
    }
}

有两种距离计算模式：arc 圆弧（默认）和 plane 平面。圆弧计算最准确。plane最快但最不准确的。当您的搜索上下文为狭窄，并且跨越较小的地理区域（约5km）时，请考虑使用plane。plane将为跨越非常大区域的搜索（例如跨大陆搜索）返回更高的误差容限。可以使用distance_type参数设置距离计算类型：

POST /museums/_search?size=0
{
    "aggs" : {
        "rings" : {
            "geo_distance" : {
                "field" : "location",
                "origin" : "52.3760, 4.894",
                "unit" : "km",
                "distance_type" : "plane",
                "ranges" : [
                    { "to" : 100 },
                    { "from" : 100, "to" : 300 },
                    { "from" : 300 }
                ]
            }
        }
    }
}

Keyed Response

将keyed标志设置为true会将一个唯一的字符串键与每个bucket相关联，并将范围作为哈希而不是数组返回：

POST /museums/_search?size=0
{
    "aggs" : {
        "rings_around_amsterdam" : {
            "geo_distance" : {
                "field" : "location",
                "origin" : "52.3760, 4.894",
                "ranges" : [
                    { "to" : 100000 },
                    { "from" : 100000, "to" : 300000 },
                    { "from" : 300000 }
                ],
                "keyed": true
            }
        }
    }
}

返回

{
    ...
    "aggregations": {
        "rings_around_amsterdam" : {
            "buckets": {
                "*-100000.0": {
                    "from": 0.0,
                    "to": 100000.0,
                    "doc_count": 3
                },
                "100000.0-300000.0": {
                    "from": 100000.0,
                    "to": 300000.0,
                    "doc_count": 1
                },
                "300000.0-*": {
                    "from": 300000.0,
                    "doc_count": 2
                }
            }
        }
    }
}

还可以自定义每个范围的key：

POST /museums/_search?size=0
{
    "aggs" : {
        "rings_around_amsterdam" : {
            "geo_distance" : {
                "field" : "location",
                "origin" : "52.3760, 4.894",
                "ranges" : [
                    { "to" : 100000, "key": "first_ring" },
                    { "from" : 100000, "to" : 300000, "key": "second_ring" },
                    { "from" : 300000, "key": "third_ring" }
                ],
                "keyed": true
            }
        }
    }
}

返回

{
    ...
    "aggregations": {
        "rings_around_amsterdam" : {
            "buckets": {
                "first_ring": {
                    "from": 0.0,
                    "to": 100000.0,
                    "doc_count": 3
                },
                "second_ring": {
                    "from": 100000.0,
                    "to": 300000.0,
                    "doc_count": 1
                },
                "third_ring": {
                    "from": 300000.0,
                    "doc_count": 2
                }
            }
        }
    }
}