NAME

       mgd77header - Create MGD77 headers from A77 files

SYNOPSIS

       mgd77header NGDC-id.a77 [  -Hheadervalues.txt ] [  -Mf[item]|r|t ] [  -V[level] ]

       Note: No space is allowed between the option flag and the associated arguments.

DESCRIPTION

       mgd77header  generates  an MGD77 header by reading A77 data (i.e., the data record portion
       of MGD77 files), determines temporal and spatial extents, ten degree  boxes  crossed,  and
       data  columns  present.  Optionally,  it  can also read an input file consisting of header
       field values (-H) to be included in program output. Header field  values  determined  from
       data and read from input are output in either MGD77 format or as a list.

REQUIRED ARGUMENTS

       NGDC-ids
              Can be one or more of five kinds of specifiers:

              1. 8-character NGDC IDs, e.g., 01010083, JA010010etc., etc.

              2. 2-character agency codes which will return all cruises from each agency.

              3. 4-character  <agency><vessel>  codes,  which  will return all cruises from those
                 vessels.

              4. =list, where list is a table with NGDC IDs, one per line.

              5. If nothing is specified we return all cruises in the data base.

              (See mgd77info -L for agency and vessel codes). If no file extension is given  then
              we  search  for files with one of the four known extensions.  The search order (and
              the extensions) tried is MGD77+ (“.nc”), MGD77T (“.m77t”), MGD77  (“.mgd77”  )  and
              plain  text  file  (“.dat”).   Use  -I  to ignore one or more of these file types).
              Cruise files will be looked for first in the current directory and  second  in  all
              directories  listed  in  $MGD77_HOME/mgd77_paths.txt  [If $MGD77_HOME is not set it
              will default to $GMT_SHAREDIR/mgd77].

OPTIONAL ARGUMENTS

       -Hheadervalues.txt
              Obtain header field values from the input text file. Each row  of  the  input  file
              should  consist of a header field name and its desired value, separated by a space.
              See below for a sample header file and for the full list of header field names.

       -Mf[item]|r|r
              List the meta-data (header) for each cruise. Append f for a formatted display. This
              will  list  individual parameters and their values, one entry per output line, in a
              format that can be searched using standard UNIX text tools.  Alternatively,  append
              the  name  of  a  particular  parameter  (you only need to give enough characters -
              starting at the beginning - to uniquely identify the item). Give - to  display  the
              list  of  all  parameter names. You may also specify the number of a parameter. For
              the raw, punchcard-formatted MGD77 original header block, append r instead. For the
              M77T format, append t instead.

       -V[level] (more …)
              Select verbosity level [c].

       -^ or just -
              Print a short message about the syntax of the command, then exits (NOTE: on Windows
              just use -).

       -+ or just +
              Print  an  extensive  usage  (help)  message,  including  the  explanation  of  any
              module-specific option (but not the GMT common options), then exits.

       -? or no arguments
              Print  a  complete  usage (help) message, including the explanation of all options,
              then exits.

HEADER ITEM SAMPLE FILE

       Format_Acronym MGD77

       Source_Institution SOEST - UNIV. OF HAWAII

       Country USA

       Platform_Name KILO MOANA

       Platform_Type_Code 1

       Platform_Type SHIP

NAMES OF ALL MGD77 HEADER FIELDS

       Survey_Identifier

       Format_Acronym

       Data_Center_File_Number

       Parameters_Surveyed_Code

       File_Creation_Year

       File_Creation_Month

       File_Creation_Day

       Source_Institution

       Country

       Platform_Name

       Platform_Type_Code

       Platform_Type

       Chief_Scientist

       Project_Cruise_Leg

       Funding

       Survey_Departure_Year

       Survey_Departure_Month

       Survey_Departure_Day

       Port_of_Departure

       Survey_Arrival_Year

       Survey_Arrival_Month

       Survey_Arrival_Day

       Port_of_Arrival

       Navigation_Instrumentation

       Geodetic_Datum_Position_Determination_Method

       Bathymetry_Instrumentation

       Bathymetry_Add_Forms_of_Data

       Magnetics_Instrumentation

       Magnetics_Add_Forms_of_Data

       Gravity_Instrumentation

       Gravity_Add_Forms_of_Data

       Seismic_Instrumentation

       Seismic_Data_Formats

       Format_Type

       Format_Description

       Topmost_Latitude

       Bottommost_Latitude

       Leftmost_Longitude

       Rightmost_Longitude

       Bathymetry_Digitizing_Rate

       Bathymetry_Sampling_Rate

       Bathymetry_Assumed_Sound_Velocity

       Bathymetry_Datum_Code

       Bathymetry_Interpolation_Scheme

       Magnetics_Digitizing_Rate

       Magnetics_Sampling_Rate

       Magnetics_Sensor_Tow_Distance

       Magnetics_Sensor_Depth

       Magnetics_Sensor_Separation

       Magnetics_Ref_Field_Code

       Magnetics_Ref_Field

       Magnetics_Method_Applying_Res_Field

       Gravity_Digitizing_Rate

       Gravity_Sampling_Rate

       Gravity_Theoretical_Formula_Code

       Gravity_Theoretical_Formula

       Gravity_Reference_System_Code

       Gravity_Reference_System

       Gravity_Corrections_Applied

       Gravity_Departure_Base_Station

       Gravity_Departure_Base_Station_Name

       Gravity_Arrival_Base_Station

       Gravity_Arrival_Base_Station_Name

       Number_of_Ten_Degree_Identifiers

       Ten_Degree_Identifier

       Additional_Documentation_1

       Additional_Documentation_2

       Additional_Documentation_3

       Additional_Documentation_4

       Additional_Documentation_5

       Additional_Documentation_6

       Additional_Documentation_7

EXAMPLES

       To generate an MGD77 header from A77 input, try

              gmt mgd77header km0201 -Hkmheaderitems.txt -Mf > km0201.h77

SEE ALSO

       mgd77info, mgd77list, mgd77manage, mgd77path, mgd77track, x2sys_init

REFERENCES

       The     Marine     Geophysical     Data     Exchange     Format     -      MGD77,      see
       http://www.ngdc.noaa.gov/mgg/dat/geodas/docs/mgd77.txt.

COPYRIGHT

       2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe