Aiming to evaluate the accuracy of ZHD determination from various sources of atmospheric pressure, a study is presented that com-pares ZHD values determined with in situ measurements of surface pressure at a global set of 63 coastal barometric sites (GNSS sta-tions), the corresponding values obtained from ECMWF operational model, ERA Interim sea level pressure (SLP) and ZHD from the Vienna Mapping Functions 1 (VMF1).