  The trip planning query searches for preferred routes starting from a given
point through multiple Point-of-Interests (PoI) that match user requirements.
Although previous studies have investigated trip planning queries, they lack
flexibility for finding routes because all of them output routes that strictly
match user requirements. We study trip planning queries that output multiple
routes in a flexible manner. We propose a new type of query called skyline
sequenced route (SkySR) query, which searches for all preferred sequenced
routes to users by extending the shortest route search with the semantic
similarity of PoIs in the route. Flexibility is achieved by the {\it semantic
hierarchy} of the PoI category. We propose an efficient algorithm for the SkySR
query, bulk SkySR algorithm that simultaneously searches for sequenced routes
and prunes unnecessary routes effectively. Experimental evaluations show that
the proposed approach significantly outperforms the existing approaches in
terms of response time (up to four orders of magnitude). Moreover, we develop a
prototype service that uses the SkySR query, and conduct a user test to
evaluate its usefulness.
