geo-distance-facet.asciidoc

Geo Distance Facets

The geo_distance facet is a facet providing information for ranges of distances from a provided geo_point including count of the number of hits that fall within each range, and aggregation information (like total).

Assuming the following sample doc:

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

Here is an example that create a geo_distance facet from a pin.location of 40,-70, and a set of ranges:

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : {
                    "lat" : 40,
                    "lon" : -70
                },
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

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

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : {
                    "lat" : 40,
                    "lon" : -70
                },
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

Lat Lon As Array

Format in [lon, lat], note, the order of lon/lat here in order to conform with GeoJSON.

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : [40, -70],
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

Lat Lon As String

Format in lat,lon.

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : "40, -70",
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

Geohash

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : "drm3btev3e86",
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

Ranges

When a to or from are not set, they are assumed to be unbounded. Ranges are allowed to overlap, basically, each range is treated by itself.

Options

Option	Description
unit	The unit the ranges are provided in. Defaults to km. Can also be mi, miles, in, inch, yd, yards, ft, feet, kilometers, mm, millimeters, cm, centimeters, m or meters.
distance_type	How to compute the distance. Can either be arc (better precision), sloppy_arc (faster) or plane (fastest). Defaults to sloppy_arc.

Value Options

On top of the count of hits falling within each range, aggregated data can be provided (total) as well. By default, the aggregated data will simply use the distance calculated, but the value can be extracted either using a different numeric field, or a script. Here is an example of using a different numeric field:

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : "drm3btev3e86",
                "value_field" : "num1",
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

And here is an example of using a script:

{
    "query" : {
        "match_all" : {}
    },
    "facets" : {
        "geo1" : {
            "geo_distance" : {
                "pin.location" : "drm3btev3e86",
                "value_script" : "doc['num1'].value * factor",
                "params" : {
                    "factor" : 5
                }
                "ranges" : [
                    { "to" : 10 },
                    { "from" : 10, "to" : 20 },
                    { "from" : 20, "to" : 100 },
                    { "from" : 100 }
                ]
            }
        }
    }
}

Note the params option, allowing to pass parameters to the script (resulting in faster script execution instead of providing the values within the script each time).

Note	geo_point Type The facet requires the geo_point type to be set on the relevant field.

Note	Multi Location Per Document The facet can work with multiple locations per document.