Abstract
Nowadays, most of tools for spatial data manipulation allow to edit information on maps without performing any integrity verification. On the other hand, data repositories such as the DBMS only permit few constraints to be defined by means of their Data Definition Languages and leave programmers to implement procedures for complex constraints. In this work we present the WiSPY system, a plugin of the GIS tool uDig for visually specifying and verifying complex spatial integrity constraints. WiSPY includes a visual environment for defining spatial data models with integrity constraints and for automatically generating the constraint checker. The latter is used by the WiSPY tool to verify the integrity of the data produced during the map editing process. The system has been validated on a real case study concerning the current regulation of the Public Illumination Plan (PIP) managed by an Italian municipality.