In many cases

the cone-based model and the direction-relation matrix model may make mistakes in determining the direction relations between two objects

owing to not properly taking into account the impacts of factors on the direction relations between two objects

such as the shape and size of the objects

as well as the distance between them. For this reason

a compound model is proposed by combining the cone-based model and the direction-relation matrix model to overcome the deficiencies of both to describe well the qualitative direction relations between two objects. The basic idea is: first

redividing all direction regions by means of the geometric operations between the cone-shaped direction regions of the cone-based model and the corresponding rectangular direction regions of the direction-relation matrix model to construct the compound model;then

getting the qualitative direction relations from the reference object to the target object by computing the intersection of the target object and each direction region of the compound model and using the matrix to store the results. The experiments show that the compound model avoids effectively the defects existing in the cone-based model and the direction-relation matrix model. Additionally

the compound model can accurately describe the qualitative direction relations between two objects and provide supports for spatial reasoning and spatial queries the defects existing in the cone-based model and the direction-relation matrix model.