Header file created and used by GEODAS ReFormat to MGD77T, a program used to format geophysical data into the Marine Geophysical Data Exchange (MGD77T) format; contains data that documents the content and structure of the data contained in the associated .M77T data file; includes the survey ID, format, ship name, country platform, project funding date, and navigation instrument.

M77T data and H77T files are created from raw data collected by marine researchers using InfoBank, a structured information storage scheme of databases and software. The raw data is collected by researchers studying underwater depth of lake and ocean floors, which is known as bathymetry. A M77T and H77T file, along with other metadata files, are used to transmit data to and from a data center for analysis. The H77T file will bear the same name as the associated M77T file. If the M77T file is named j295gb.m77t, the H77T file is named j295gb.h77t. NOTE: The GEODAS ReFormat to MGD77T is no longer available for download.