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$geoWithin（查询谓词操作符）

定义

$geoWithin

选择地理空间数据完全位于指定形状内的文档。

The specified shape can be either a GeoJSON Polygon (either single-ringed or multi-ringed), a GeoJSON MultiPolygon, or a shape defined by legacy coordinate pairs. The $geoWithin operator uses the $geometry operator to specify the GeoJSON object.

要使用默认坐标参考系 (CRS) 指定 GeoJSON 多边形或多多边形，请使用以下语法：

{
   <location field>: {
      $geoWithin: {
         $geometry: {
            type: <"Polygon" or "MultiPolygon"> ,
            coordinates: [ <coordinates> ]
         }
      }
   }
}

For $geoWithin queries that specify GeoJSON geometries with areas greater than a single hemisphere, the use of the default CRS results in queries for the complementary geometries.

要使用自定义 MongoDB CRS 指定单环 GeoJSON 多边形，请在 $geometry 表达式中使用指定自定义 MongoDB CRS 的原型：

{
   <location field>: {
      $geoWithin: {
         $geometry: {
           type: "Polygon" ,
           coordinates: [ <coordinates> ],
           crs: {
              type: "name",
              properties: { name: "urn:x-mongodb:crs:strictwinding:EPSG:4326" }
           }
         }
      }
   }
}

The custom MongoDB CRS uses a counter-clockwise winding order and allows $geoWithin to support queries with a single-ringed GeoJSON polygon whose area is greater than or equal to a single hemisphere. If the specified polygon is smaller than a single hemisphere, the behavior of $geoWithin with the MongoDB CRS is the same as with the default CRS. See also "Big" Polygons.

如果查询是否包含在由平面上的传统坐标对定义的形状中，请使用以下事务语法：

{
   <location field>: {
      $geoWithin: { <shape operator>: <coordinates> }
   }
}

可用形状操作符包括：

$box,
$polygon,
$center （定义一个圆），且
$centerSphere （在球体上定义一个圆）。

重要

如果使用经度和纬度，请按照 longitude, latitude 的顺序指定坐标。

行为

地理空间索引

$geoWithin不需要地理空间索引。但是，地理空间索引可提高查询性能。2 dsphere 和2 d地理空间索引都支持 $geoWithin。

未排序的结果

The $geoWithin operator does not return sorted results. As such, MongoDB can return $geoWithin queries more quickly than geospatial $near or $nearSphere queries, which sort results.

退化几何图形

$geoWithin 不保证它会考虑一个几何体来纳入其组件几何体，或另一个共享其组件几何体的多边形。

“大”多边形

For $geoWithin, if you specify a single-ringed polygon that has an area greater than a single hemisphere, include the custom MongoDB coordinate reference system in the $geometry expression. Otherwise, $geoWithin queries for the complementary geometry. For all other GeoJSON polygons with areas greater than a hemisphere, $geoWithin queries for the complementary geometry.

示例

在多边形内

以下示例选择了完全存在于 GeoJSON Polygon 中的所有 loc 数据。多边形的面积小于单半球的面积：

db.places.find(
   {
     loc: {
       $geoWithin: {
          $geometry: {
             type : "Polygon" ,
             coordinates: [ [ [ 0, 0 ], [ 3, 6 ], [ 6, 1 ], [ 0, 0 ] ] ]
          }
       }
     }
   }
)

对于面积大于单半球的单环多边形，请参阅在“大型”多边形内。

在“大型”多边形内

如需使用面积大于单个半球的单环 GeoJSON 多边形进行查询，$geometry 表达式必须指定自定义 MongoDB 坐标参考系。例如：

db.places.find(
   {
     loc: {
       $geoWithin: {
          $geometry: {
             type : "Polygon" ,
             coordinates: [
               [
                 [ -100, 60 ], [ -100, 0 ], [ -100, -60 ], [ 100, -60 ], [ 100, 60 ], [ -100, 60 ]
               ]
             ],
             crs: {
                type: "name",
                properties: { name: "urn:x-mongodb:crs:strictwinding:EPSG:4326" }
             }
          }
       }
     }
   }
)