[[query-dsl-geo-distance-query]]
== Geo Distance Query

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

[source,js]
--------------------------------------------------
{
    "pin" : {
        "location" : {
            "lat" : 40.12,
            "lon" : -71.34
        }
    }
}
--------------------------------------------------

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

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

[float]
=== 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:

[float]
==== Lat Lon As Properties

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

[float]
==== Lat Lon As Array

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

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

[float]
==== Lat Lon As String

Format in `lat,lon`.

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

[float]
==== Geohash

[source,js]
--------------------------------------------------
{
    "filtered" : {
        "query" : {
            "match_all" : {}
        },
        "filter" : {
            "geo_distance" : {
                "distance" : "12km",
                "pin.location" : "drm3btev3e86"
            }
        }
    }
}
--------------------------------------------------

[float]
=== Options

The following are options allowed on the filter:

[horizontal]

`distance`::

    The radius of the circle centred on the specified location. Points which
    fall into this circle are considered to be matches. The `distance` can be
    specified in various units. See <<distance-units>>.

`distance_type`::

    How to compute the distance. Can either be `sloppy_arc` (default), `arc` (slightly more precise but significantly slower) or `plane` (faster, but inaccurate on long distances and close to the poles).

`optimize_bbox`::

    Whether to use the optimization of first running a bounding box check
    before the distance check. Defaults to `memory` which will do in memory
    checks. Can also have values of `indexed` to use indexed value check (make
    sure the `geo_point` type index lat lon in this case), or `none` which
    disables bounding box optimization.


[float]
=== geo_point Type

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

[float]
=== 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.