如何在 Elasticsearch 中查找包含给定点的多边形

Question

我需要在包含大约 50k 地形多边形（在 ES 上存储为 geo_shape 多边形）的数据库上构建一个查询，我在其中给出一个点，它会返回包含该点的每个多边形。

我设法使用渗透查询（下面的示例）来做到这一点，但我在某处读到渗透查询不能很好地扩展。

有没有更有效的方法来实现这种行为？

使用渗透的示例：

Demo polygons

PUT geo_demo
{
  "mappings": {
    "properties": {
      "thepoly": {
        "type": "percolator"
      },
      "thepoint": {
        "type": "geo_point"
      }
    }
  }
}

#region 1 (red)
POST /geo_demo/_doc/1
{
  "thepoly": {
    "bool": {
      "must": {
        "match_all": {}
      },
      "filter": {
        "geo_polygon": {
          "thepoint": {
            "points": [
              "-23.573978,-46.664806",
              "-23.583978,-46.664806",
              "-23.583978,-46.658806",
              "-23.573978,-46.658806",
              "-23.573978,-46.664806"
            ]
          }
        }
      }
    }
  }
}

#region 2 (green)
POST /geo_demo/_doc/2
{
  "thepoly": {
    "bool": {
      "must": {
        "match_all": {}
      },
      "filter": {
        "geo_polygon": {
          "thepoint": {
            "points": [
              "-23.579978,-46.664806",
              "-23.583978,-46.664806",
              "-23.583978,-46.652806",
              "-23.579978,-46.652806",
              "-23.579978,-46.664806"
            ]
          }
        }
      }
    }
  }
}

#should match doc/1 only
GET /geo_demo/_search
{
  "query": {
    "percolate": {
      "field": "thepoly",
      "document": {
        "thepoint": "-23.577007,-46.661811"
      }
    }
  }
}

#should match both doc/1 and doc/2
GET /geo_demo/_search
{
  "query": {
    "percolate": {
      "field": "thepoly",
      "document": {
        "thepoint": "-23.582002,-46.661811"
      }
    }
  }
}

#should match doc/2 only
GET /geo_demo/_search
{
  "query": {
    "percolate": {
      "field": "thepoly",
      "document": {
        "thepoint": "-23.582041,-46.655717"
      }
    }
  }
}

#should match none
GET /geo_demo/_search
{
  "query": {
    "percolate": {
      "field": "thepoly",
      "document": {
        "thepoint": "-23.576771,-46.655674"
      }
    }
  }
}

Answer 1

你几乎不需要 elasticsearch，除非你有充分的理由。

对于 50K 多边形，您可以轻松地将它们保存在堆中，或者将每个多边形分解为 geohashes 列表。

你可以有一个以 geohash 作为键，多边形 id 作为值的堆内映射。

当您输入点时，您首先计算 geohash，然后使用 Map#get 检查该点在地图中或哪些多边形包含该点。