  Consistent query answering is an inconsistency tolerant approach to obtaining
semantically correct answers from a database that may be inconsistent with
respect to its integrity constraints. In this work we formalize the notion of
consistent query answer for spatial databases and spatial semantic integrity
constraints. In order to do this, we first characterize conflicting spatial
data, and next, we define admissible instances that restore consistency while
staying close to the original instance. In this way we obtain a repair
semantics, which is used as an instrumental concept to define and possibly
derive consistent query answers. We then concentrate on a class of spatial
denial constraints and spatial queries for which there exists an efficient
strategy to compute consistent query answers. This study applies inconsistency
tolerance in spatial databases, rising research issues that shift the goal from
the consistency of a spatial database to the consistency of query answering.
