The reliability of information derived from spatial data is described in order to establish criteria for auditing a spatial database. The evaluation of the accuracy of data batter was obtained from a series of indices such as omission and commission errors, Geary's C, Moran's I and Kappa index. The evaluation method to deduce the accuracy of geochemical data has to be used in the initial stage in geological projects using Geographic Information Systems (GIS). The results indicate that it is possible to get a better knowledge of the accuracy of the used data and its real capacity to be modeled in a GIS environment. (C) 2004 Elsevier B.V. All rights reserved.84293101