# BIASDISTSPHERICAL

The `BIASDISTSPHERICAL` field specifier allows you to boost the score of any document according to its distance from a specified point using spherical coordinates (latitude/longitude).

TIP: If your document location fields contain regions (in Well-known text POLYGON format), the `BIASDISTSPERHICAL` operator calculates distances from the geometric center of the region.

## Format

    FieldText=BIASDISTSPHERICAL{lat,long,range,maxboost}:LOCATION

`lat` | The specified latitude. Specify latitude positions south of the equator as negative.
`long` | The specified longitude. Specify longitude positions west of the Greenwich Meridian as negative.
`range` | The distance in kilometers from the specified latitude and longitude.
`maxboost` | The maximum percentage to boost the result.
`LOCATION` | The document field or fields that contain the location value. You can use one of the following options to specify location fields: a single field. This field must contain a Well-known text format POINT or POLYGON definition (for example, `POINT (x y)`). This field must be a unified GeospatialType field. two fields, in the format `LATFIELD:LONGFIELD`, where `LATFIELD` is the field that contains the latitude value, and `LONGFIELD` is the field that contains the longitude value. You must specify the fields in the order `latitude:longitude`. The fields must be NumericType or GeospatialType.

## Example

    FieldText=BIASDISTSPHERICAL{52.2,0.1,100,7}:LAT:LONG

    FieldText=BIASDISTSPHERICAL{52.2,0.1,100,7}:LOCATION

In these examples, all documents within 100 kilometers of the point `(lat,long)=(52.2,0.1)` are given a relevance boost. The maximum boost of `7` percent is given to documents at the given point. The boost decreases linearly down to 0 boost at 100 kilometers.

In the first example, the location data is stored in two document fields, `LAT` and `LONG`. In the second example, the location data is stored in a single `LOCATION` field.

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