$box¶

Definition定义¶

$box¶

Specifies a rectangle for a geospatial $geoWithin query to return documents that are within the bounds of the rectangle, according to their point-based location data. 为地理空间$geoWithin查询指定一个矩形，以根据基于点的位置数据返回矩形边界内的文档。When used with the $box operator, $geoWithin returns documents based on grid coordinates and does not query for GeoJSON shapes.当与$box运算符一起使用时，$geoWithin根据网格坐标返回文档，并且不查询GeoJSON形状。

To use the $box operator, you must specify the bottom left and top right corners of the rectangle in an array object:要使用$box运算符，必须指定数组对象中矩形的左下角和右上角：

{
  <location field>: {
     $geoWithin: {
        $box: [
          [ <bottom left coordinates> ],
          [ <upper right coordinates> ]
        ]
     }
  }
}

Important

If you use longitude and latitude, specify longitude first.如果使用经度和纬度，请先指定经度。

Behavior行为¶

The query calculates distances using flat (planar) geometry.该查询使用平面几何图形计算距离。

Applications can use $box without having a geospatial index. 应用程序可以使用$box，而无需地理空间索引。However, geospatial indexes support much faster queries than the unindexed equivalents.然而，地理空间索引支持的查询速度要比未索引的索引快得多。

Only the 2d geospatial index supports $box.只有2d地理空间索引支持$box。

Example示例¶

The following example query returns all documents that are within the box having points at: [ 0 , 0 ], [ 0 , 100 ], [ 100 , 0 ], and [ 100 , 100 ].下面的示例查询返回框中的所有文档，这些文档的点位于：[0,0]、[0,100]、[100,0]和[100,100]。

db.places.find( {
   loc: { $geoWithin: { $box:  [ [ 0, 0 ], [ 100, 100 ] ] } }
} )