Anomalously low value May 1959 - correct as received from authority.
Documentation added 2012-01-12
Regarding the comment above re. the data spike in May 1959. In the old system it was only possible to flag a whole year as suspect. This is not the case with the new database. As the rest of the data for 1959 looks correct the flags have been removed so May 1959 is the only month flagged.
Documentation added 2015-06-24
Levelling information has been received from UNAM. Primary benchmark remains BM 1. However the TGZ is now 12.301m below BM 1.
Servicio Mareografico Nacional Instituto de Geofisica, Ciudad Universitaria Delegacion de Coyoacan 04510 Mexico D.F.