ABSTRACT
ABSTRACT: One class of spatial relations, the Internal Cardinal Direction (ICD) relation, is introduced and investigated in this paper. Based on the ICD-9 model that includes nine atomic base relations, the characteristics and simplification rules for the ICD model are discussed first. Then the ICD relations involved in qualitative spatial reasoning, including four composition cases, are proposed formally. They are: composing two nesting ICD relations; composing two coordinate ICD relations to deduce conventional (or external) cardinal direction relations; qualitative distance relations; and topological relations. In terms of ICD relations, the container object determines the scale of spatial analysis and forms a positioning framework together with ICD relation predications. Consequently, research on ICD related reasoning should contribute to the representation and processing of survey knowledge.
