The POLYGON
field specifier (case sensitive) allows you to find documents whose X/Y position is within a specified polygonal shape.
FieldText=POLYGON{coordX,coordY,coordX,coordY,...}:X:Y
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. 
X

is the document field that contains the X coordinate. 
Y

is the document field that contains the Y coordinate. 
You must always specify two 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.
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).
