A method for evaluating a spatial query comprises receiving a spatial
query defining a query window including a void, identifying an interior
circle for the query window, wherein the interior circle includes a void,
and processing the spatial query by either (1) modifying the at least one
interior circle to exclude the void, and using the modified interior
circle to evaluate the spatial query by checking whether a data MBR is
inside the modified interior circle and when it does, including the data
item in the query result set, or (2) by checking whether a data MBR is
inside the interior circle and when it does, checking whether the data
MBR intersects the MBRs of any of the voids, and including the data item
in the query result set when there is no intersection.