2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/183927We compare three different methods to evaluate uncertainties in the Earth's matter density profile, which are relevant to long baseline experiments, such as neutrino factories.3 pages, 1 figure. Talk given at the NuFact'02 Workshop, London, 1-6 July, 2002High Energy Physics - Phenomenologytext