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IAGA2002 Data Exchange Format
Revision December 2001

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This is Dec., 2001 Version
Additions made Aug. 2011  => http://www.ngdc.noaa.gov/IAGA/vdat/iagaformat.html

This file provides information on the IAGA ASCII Exchange Format, adopted August 2001. Content
includes some general information and description of the file header, comment records, data header
and records, file naming recommendations, and sample data file.

This format is intended as a data exchange format for geomagnetic data (samples and means) from
observatories and variometer stations at time intervals from millisecond up to and including monthly
means. The format comprises:

            Twelve (12) mandatory file header records 
            Unlimited optional comment records 
            One (1) mandatory data header record 
            A series of data records. 
            Every record is 70 characters long plus the machine-dependent carriage return / line
            feed. 

Pad records with spaces if needed. Data records report exactly 4 magnetic field elements (DHIF, DHZF,
or XYZF). Use missing data values (8's or 9's) if fewer than 4 elements are available.

The 12 mandatory file header records

Mandatory header and optional comment records begin with a space character in column 1 and end with
the vertical bar | (ASCII 124) in column 70. Content labels begin in column 2 and descriptions begin
in column 25.

      This format is designated IAGA-2002. 
      Source of Data is the name of the institute responsible for collecting the data. 
      Please spell the entire station name; do not use abbreviations. Capitalize the first letter. 
      The IAGA Code is the official IAGA 3-letter station code. It should be in capital letters and
      correspond to the IAGA list of magnetic observatories. Variation stations must check observer
      suggested 3-letter codes against the IAGA list (WDC SEG, Boulder) and confirm through the IAGA
      Division V WG1 or leave the code blank. 

      Location of the station is reported to the one thousandth degree in geodetic latitude
      (positive north) from -90 to 90 degrees and in geodetic longitude (positive east) from --180
      to 180 or 0 to 360 degrees. 

      Report elevation in meters above mean sea level. 
      Reported refers to the magnetic field elements contained in the data record, in the order
      recorded in data record. Valid values are DHIF, DHZF, and XYZF. Use E/V instead of D/I for
      declination/inclination given in intensity units (ONLY if data type is variation). 
      Sensor Orientation is the physical orientation of the observing instruments, i.e. XYZF, HDZ. 
      Digital Sampling is the rate (in seconds) of the data sampling of the magnetic field sensor
      (instrument) or the digitizing interval for analogue data. 
      Data interval type is the mean or instantaneous time interval of the data. Common values
      include 1-minute (00:30-01:29), 1-minute (00:00-00:59), 1-hour (00-59), 1-day (00-23) and
      1-month (01-31); the last day could also be 30, 29, or 28. There are many possible intervals,
      including a fraction of a second (instant value), averages by 1-second (501-1500), 1- second
      (0-1000), 10 second, or 2.5 minute. Define the type of mean and how values are centered
      in the comment section. 
      Data type is provisional, definitive, or variation 


The optional comment header records

Use these records to record important information concerning the data that is not contained in the
defined fields. Types of information may include the type of means and how the mean values are
centered, important gaps in the data record, or explanations of missing values (9 filled element
field).

      Every record begins with a space character in column 1 and # (hash or number sign) in column 2. 
      The end of each record is indicated with a vertical bar | (ASCII 124) in column 70. 
      Include the formula for computing the missing (non-reported) magnetic elements. For example, if
      an observatory reports XYZF, the comments should contain the formula for computing HDI. 


The mandatory data header record

The mandatory data-header record contains column headers useful for multi- station analysis.
Elements, both type and order, are indicated in the file-header field Reported.

      The date and time headers are DATE, TIME, and DOY (day of year). 
      The magnetic element headers comprise 4 letters: 3 letters for the observatory IAGA code and 1
      letter for the magnetic element reported. Valid values are H, D (or E), I (or V), X, Y, Z, F.
      The column headers are space delimited. 

      The end of each record is indicated with a vertical bar | (ASCII 124) in column 70. 

The data records

The data records contain the date, time, and magnetic field elements reported. Report data to the
least significant digit. Indicate missing data with 99999 to the corresponding accuracy for a given
component (e.g., 99999.0 or 99999.00). If an element is not observed, please record 88888 (to the
corresponding accuarcy) in that field. The format for field elements is 4(1X, F9.2). Each record is
exactly 70 characters long plus the machine dependent carriage return / line feed.

      DATE is the calendar date in ISO YYYY-MM-DD format (4-digit year, month as 01-12, day as 01-31).
      TIME is in ISO hh:mm:ss.sss format (hour as 0-24, minute as 0-59, second as 0-59 Note: if the
      hour is 24, the minute and second must be 0). 

      Values beyond the time interval of the means being reported must be zero-filled i.e.
      14:01:00.000 for 1 minute data for the 14th hour, first minute. DOY is the day of the year, from
      1 - 365 (or 366 for leap years). Describe the method of average, i.e., centered to the hour for
      hourly means, in the comments area.

      D and I are reported in angular units of minutes of arc to the precision of the instruments. 
      F, H, X, Y, Z, E, and V are reported in nanotesla and a fraction of nT. 

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Sample format: IAGA-2002 - November 2001 Revision
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