Topological predicates are an important element of database systems that allow manipulation of spatial data. Based on the necessity for such systems to handle uncertainty, we introduce a general mechanism that identifies vague topological predicates. This definition forms part of a formal data model referred to as VASA (Vague Spatial Algebra), in which the data types vague regions, vague lines, and vague points are defined in terms of existing definition of crisp spatial data types. Following this trend, the mechanism presented here identifies vague topological predicates on the basis of well defined crisp topological predicates. An example implementation of the mechanism for vague regions is given.