In this paper, we describe an empirical study we conducted on the application of a simplification algorithm, meant to understand which factors affect the human’s perception of map changes. In the study, three main factors have been taken into account, namely Number of Polygons, Number of Vertices and Screen Resolution. An analysis of variance (ANOVA) test has been applied in order to compute such evaluations. As a result, number of vertices and screen resolution turn out to be effective factors influencing the human’s perception while number of polygons as well as interaction among the factors do not have any impact on the measure.