To calculate geometry over an Earth-like sphere, store your location
data as :doc:`GeoJSON objects </reference/geojson>`.

.. include:: /includes/extracts/geojson-specification-geospatial.rst

.. _geospatial-legacy:

Legacy Coordinate Pairs

:doc:`2dsphere </core/2dsphere>` indexes support queries that calculate
:ref:`geometries on an earth-like sphere <geospatial-geometry>`.

.. include:: /includes/create-2dsphere-index.rst

For more information on the ``2dsphere`` index, see
:doc:`/core/2dsphere`.

.. _geo-2d:

``2d``
~~~~~~

:doc:`2d </core/2d>` indexes support queries that calculate
:ref:`geometries on a two-dimensional plane <geospatial-geometry>`.
Although the index can support :query:`$nearSphere` queries that
calculate on a sphere, if possible, use the :ref:`geo-2dsphere` index
for spherical queries.

.. include:: /includes/create-2d-index.rst

For more information on the ``2d`` index, see :doc:`/core/2d`.

Geospatial Indexes and Sharded Collections

.. include:: /includes/fact-geospatial-index-covered-query.rst

Geospatial Queries
------------------

.. note::

   .. include::  /includes/extracts/geospatial-queries-longitude-values.rst

Geospatial Query Operators

MongoDB provides the following geospatial :doc:`aggregation pipeline
stage </core/aggregation-pipeline>`:

.. list-table::
   :header-rows: 1
   :widths: 38 72

   * - Stage

     - Description

   * - :pipeline:`$geoNear`

     - .. include:: /includes/extracts/geoNear-stage-toc-description.rst

       .. include:: /includes/extracts/geoNear-stage-index-requirement.rst

For more details, including examples, see :pipeline:`$geoNear`
reference page.

.. _geospatial-geometry:

Geospatial Models
-----------------

MongoDB geospatial queries can interpret geometry on a flat surface or
a sphere.

``2dsphere`` indexes support only spherical queries (i.e. queries that
interpret geometries on a spherical surface).

``2d`` indexes support flat queries (i.e. queries that interpret
geometries on a flat surface) and some spherical queries. While ``2d``
indexes support some spherical queries, the use of ``2d`` indexes for
these spherical queries can result in error. If possible, use
``2dsphere`` indexes for spherical queries.

The following table lists the geospatial query operators, supported
query, used by each geospatial operations:

.. list-table::
   :header-rows: 1
   :widths: 48, 12, 40

   * - Operation

     - Spherical/Flat Query

     - Notes

   * - :query:`$near` (:ref:`GeoJSON <geospatial-geojson>` centroid
       point in this line and the following line, :ref:`2dsphere
       <geo-2dsphere>` index)

     - Spherical

     - See also the :query:`$nearSphere` operator, which provides the
       same functionality when used with :ref:`GeoJSON
       <geospatial-geojson>` and a :ref:`2dsphere <geo-2dsphere>` index.

   * - :query:`$near` (:ref:`legacy coordinates <geospatial-legacy>`, :ref:`2d <geo-2d>` index)

     - Flat

     -

   * - :query:`$nearSphere` (:ref:`GeoJSON <geospatial-geojson>` point, :ref:`2dsphere <geo-2dsphere>` index)

     - Spherical

     - Provides the same functionality as :query:`$near` operation that
       uses :ref:`GeoJSON <geospatial-geojson>` point and a
       :ref:`2dsphere <geo-2dsphere>` index.

       For spherical queries, it may be preferable to use
       :query:`$nearSphere` which explicitly specifies the spherical
       queries in the name rather than :query:`$near` operator.

   * - :query:`$nearSphere` (:ref:`legacy coordinates <geospatial-legacy>`, :ref:`2d <geo-2d>` index)

     - Spherical

     - Use :term:`GeoJSON` points instead.

   * - :query:`$geoWithin` : { :query:`$geometry`: ... }

     - Spherical

     -

   * - :query:`$geoWithin` : { :query:`$box`: ... }

     - Flat

     -

   * - :query:`$geoWithin` : { :query:`$polygon`: ... }

     - Flat

     -

   * - :query:`$geoWithin` : { :query:`$center`: ... }

     - Flat

     -

   * - :query:`$geoWithin` : { :query:`$centerSphere`: ... }

     - Spherical

     -

   * - :query:`$geoIntersects`

     - Spherical

     -


   * - :pipeline:`$geoNear` aggregation stage (:ref:`2dsphere <geo-2dsphere>` index)
     - Spherical
     -

   * - :pipeline:`$geoNear` aggregation stage (:ref:`2d <geo-2d>` index)
     - Flat
     -

Example
-------

Create a collection ``places`` with the following documents:

.. code-block:: javascript

   db.places.insert( {
       name: "Central Park",
      location: { type: "Point", coordinates: [ -73.97, 40.77 ] },
      category: "Parks"
   } );
   db.places.insert( {
      name: "Sara D. Roosevelt Park",
      location: { type: "Point", coordinates: [ -73.9928, 40.7193 ] },
      category: "Parks"
   } );
   db.places.insert( {
      name: "Polo Grounds",
      location: { type: "Point", coordinates: [ -73.9375, 40.8303 ] },
      category: "Stadiums"
   } );

The following operation creates a ``2dsphere`` index on the
``location`` field:

.. code-block:: javascript

   db.places.createIndex( { location: "2dsphere" } )

The following query uses the :query:`$near` operator to return
documents that are at least 1000 meters from and at most 5000 meters
from the specified GeoJSON point, sorted in order from nearest to
farthest:

.. code-block:: javascript

   db.places.find(
      {
        location:
          { $near:
             {
               $geometry: { type: "Point",  coordinates: [ -73.9667, 40.78 ] },
               $minDistance: 1000,
               $maxDistance: 5000
             }
          }
      }
   )

The following operation uses the :pipeline:`geoNear` aggregation
operation to return documents that match the query filter ``{ category:
"Parks" }``, sorted in order of nearest to farthest to the specified
GeoJSON point:

.. code-block:: javascript

   db.places.aggregate( [
      {
         $geoNear: {
            near: { type: "Point", coordinates: [ -73.9667, 40.78 ] },
            spherical: true,
            query: { category: "Parks" },
            distanceField: "calcDistance"
         }
      }
   ] )

.. toctree::
   :titlesonly:
   :hidden:

   /tutorial/geospatial-tutorial
   /reference/geojson

https://yq.aliyun.com/articles/241?spm=a2c4e.11153987.0.0.626677075lskRD
https://blog.csdn.net/mfkjq/article/details/80377114