Geographical Information Systems (GIS) can be used to make transect sampling when non-moving objects are to be counted, involving choosing a line or series of lines along which the counts are to take place. This approach has been used by us in order to study canine faecal contamination in the city of Naples (southern Italy), and to evaluate the consequent presence of canine parasitic elements. A GIS was constructed utilizing the geo-referenced digital photographs and the cadastral maps of Naples. In order to uniformly evaluate the canine faecal contamination throughout the city, a grid representing sub-areas of 1 km x 700 m was overlaid on the city map within the GIS. The territory of Naples was divided in 218 equal, rectangular sub-areas. In each sub-area a 1 km transect was drawn, and digitalized on-screen in the GIS. Canine faeces (copros in Greek) were counted along the transects in 143 sub-areas. In these sub-areas, 415 copros were collected and examined. Out of the 143 sub-areas, 141 contained canine copros. The results of the negative binomial regression model showed a positive association between the number of copros and the human population density. Out of the total of 415 copros, 70 (16.9%) were positive for parasitic elements; eggs of Toxocara canis, Toxascaris leonina, Ancylostoma caninum and Trichuris vulpis were found, as well as oocysts of Isospora canis.