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我正在尝试将一个集合中的点与存储在另一个集合中的区域进行匹配。以下是文档示例。

要点：

{ 
  "_id" : ObjectId("5e36d904618c0ea59f1eb04f"), 
  "gps" : { "lat" : 50.073288, "lon" : 14.43979 },  
  "timeAdded" : ISODate("2020-02-02T15:13:22.096Z") 
}

地区：

{
  "_id" : ObjectId("5e49a469afae4a11c4ff3cf7"), 
  "type" : "Feature", 
  "geometry" : { 
    "type" : "Polygon", 
    "coordinates" : [ 
      [ 
        [ -748397.88, -1049211.61 ], 
        [ -748402.77, -1049212.2 ],
        ... 
        [ -748410.41, -1049213.11 ], 
        [ -748403.05, -1049070.62 ]
      ] 
    ] 
  }, 
  "properties" : {  
    "Name" : "Region 1" 
  } 
}

我试图构建的查询是这样的：

db.points.aggregate([
  {$project: {
    coordinates: ["$gps.lon", "$gps.lat"]
  }}, 
  {$lookup: {
    from: "regions", pipeline: [
      {$match: {
        coordinates: {
          $geoWithin: {
            $geometry: {
              type: "Polygon", 
              coordinates: "$geometry.coordinates"
            }
          }
        }
      }}
    ], 
    as: "district"
  }}
])

我收到一个错误：

断言：命令失败：{

    "ok" : 0,
    "errmsg" : "Polygon coordinates must be an array",
    "code" : 2,
    "codeName" : "BadValue"

} : 聚合失败

我注意到 $geoWithin 文档的结构与每个区域的结构相同。所以我尝试了这样的查询：

db.points.aggregate([
  {$project: {
    coordinates: ["$gps.lon", "$gps.lat"]
  }}, 
  {$lookup: {
    from: "regions", pipeline: [
      {$match: {
        coordinates: {
          $geoWithin: "$geometry.coordinates"
        }
      }}
    ], 
    as: "district"
  }}
])

错误是一样的。

我查找了地理查询，但令人惊讶的是，所有发现的提及都有静态区域文档，而不是从集合中获取的。所以我想知道 - 是否有可能将点与两个文档集合都不是静态的并且取自数据库的区域进行映射？

4

1 回答 1

0

不幸的是不可能

You could perform query below if $geometry could deal with MongoDB Aggregation Expressions.

db.points.aggregate([
  {
    $lookup: {
      from: "regions",
      let: {
        coordinates: [
          "$gps.lon",
          "$gps.lat"
        ]
      },
      pipeline: [
        {
          $addFields: {
            coordinates: "$$coordinates"
          }
        },
        {
          $match: {
            coordinates: {
              $geoWithin: {
                $geometry: {
                  type: "Polygon",
                  coordinates: "$geometry.coordinates"
                }
              }
            }
          }
        }
      ],
      as: "district"
    }
  }
])
于 2020-02-18T02:31:09.707 回答