.. _es-guide-reference-query-dsl-geo-distance-filter:

===================
Geo Distance Filter
===================

Filters documents that include only hits that exists within a specific distance from a geo point. Assuming the following indexed json:


.. code-block:: js


    {
        "pin" : {
            "location" : {
                "lat" : 40.12,
                "lon" : -71.34
            }
        }
    }


Then the following simple query can be executed with a **geo_distance** filter:


.. code-block:: js


    {
        "filtered" : {
            "query" : {
                "match_all" : {}
            },
            "filter" : {
                "geo_distance" : {
                    "distance" : "200km",
                    "pin.location" : {
                        "lat" : 40,
                        "lon" : -70
                    }
                }
            }
        }
    }    


Accepted Formats
================

In much the same way the **geo_point** type can accept different representation of the geo point, the filter can accept it as well:


Lat Lon As Properties
---------------------

.. code-block:: js


    {
        "filtered" : {
            "query" : {
                "match_all" : {}
            },
            "filter" : {
                "geo_distance" : {
                    "distance" : "12km",
                    "pin.location" : {
                        "lat" : 40,
                        "lon" : -70
                    }
                }
            }
        }
    }


Lat Lon As Array
----------------

Format in **[lon, lat]**, note, the order of lon/lat here in order to conform with `GeoJSON <http://geojson.org/>`_.  

.. code-block:: js


    {
        "filtered" : {
            "query" : {
                "match_all" : {}
            },
            "filter" : {
                "geo_distance" : {
                    "distance" : "12km",
                    "pin.location" : [40, -70]
                }
            }
        }
    }


Lat Lon As String
-----------------

Format in **lat,lon**.


.. code-block:: js


    {
        "filtered" : {
            "query" : {
                "match_all" : {}
            },
            "filter" : {
                "geo_distance" : {
                    "distance" : "12km",
                    "pin.location" : "40,-70"
                }
            }
        }
    }


Geohash
-------

.. code-block:: js


    {
        "filtered" : {
            "query" : {
                "match_all" : {}
            },
            "filter" : {
                "geo_distance" : {
                    "distance" : "12km",
                    "pin.location" : "drm3btev3e86"
                }
            }
        }
    }


Options
=======

The following are options allowed on the filter:

===================  ================================================================================================================================================================================================================================
 Option               Description                                                                                                                                                                                                                    
===================  ================================================================================================================================================================================================================================
**distance**         The distance to include hits in the filter. The distance can be a numeric value, and then the **distance_unit** (either **mi**/**miles** or **km** can be set) controlling the unit. Or a single string with the unit as well.  
**distance_type**    How to compute the distance. Can either be **arc** (better precision) or **plane** (faster). Defaults to **arc**.                                                                                                               
===================  ================================================================================================================================================================================================================================

geo_point Type
==============

The filter *requires* the **geo_point** type to be set on the relevant field.


Multi Location Per Document
===========================

The **geo_distance** filter can work with multiple locations / points per document. Once a single location / point matches the filter, the document will be included in the filter.


Caching
=======

The result of the filter is not cached by default. The `_cache` can be set to `true` to cache the *result* of the filter. This is handy when the same point and distance parameters are used on several (many) other queries. Note, the process of caching the first execution is higher when caching (since it needs to satisfy different queries).