  The area query, to find all elements contained in a specified area from a
certain set of spatial objects, is a very important spatial query widely
required in various fields. A number of approaches have been proposed to
implement this query, the best known of which is to obtain a rough candidate
set through spatial indexes and then refine the candidates through geometric
validations to get the final result. When the shape of the query area is a
rectangle, this method has very high efficiency. However, when the query area
is irregular, the candidate set is usually much larger than the final result
set, which means a lot of redundant detection needs to be done, thus the
efficiency is greatly limited. In view of this issue, we propose a method of
iteratively generating candidates based on Voronoi diagrams and apply it to
area queries. The experimental results indicate that with our approach, the
number of candidates in the process of area query is greatly reduced and the
efficiency of the query is significantly improved.
