# Fields that Contain Coordinates within a Specified Area

## POLYGON

The `POLYGON` field specifier (case sensitive) allows you to find documents that contain a location that wholly fits within a specified polygonal shape.

You can specify the document position fields either as a pair of fields (corresponding to X and Y coordinate fields), or a single field that uses POINT or POLYGON definitions to specify position information (for example, a unified `GeospatialType` field). If you use unified fields and the document contains a POLYGON definition, the document matches only if the polygon fits wholly within the polygon you specify in the field operator.

    FieldText=POLYGON{coordX,coordY,coordX,coordY,...}:POSITION

where:

`coordX,coordY` | are the coordinates for one of the vertices. Specify an x,y pair of coordinates for each vertex of the polygon, working either clockwise or counterclockwise around the polygon. You can specify a concave polygon, but the edges must not cross themselves. You can specify coordinates with decimal numbers.
`POSITION` | The document field or fields that contain the position value. You can use one of the following options to specify location fields: a single field. This field must contain unified geospatial position information (that is, Well-known text format POINT or POLYGON definitions). two fields, in the format `X:Y`, where `X` is the field that contains the x coordinate, and `Y` is the field that contains the y coordinate. You must specify the fields in the order `x:y`. You can specify more than one pair of fields in the form `X1:Y1:X2:Y2` and so on. You can specify multiple options for the location fields, in form :`POSITION1:POSITION2:POSITION3`, and so on. This form can include a mix of types (unified location fields and split latitude and longitude fields). NOTE: If you use multiple position fields or field pairs, IDOL Server cannot match documents where a pair of split geospatial fields occurs interleaved with other geospatial fields. For example, if you use `X1:Y1:POSITION` in your query, and these fields occur in a document in the order `X1`, `POSITION`, `Y1`, IDOL Server does not match that document. In such cases, you can rewrite the query, in the form `POLYGON{...}:X1:Y1 OR POLYGON{...}:POSITION`

For example:

    FieldText=POLYGON{1,1,-1,1,0,-2,1,-1}:XPOS:YPOS

This example matches all documents whose (X,Y) position is within the quadrilateral with vertices at (1,1), (–1,1), (0,–2), (1,–1).

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