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# Intermagnet CD Data Viewer Help

# WDC Data Format

## Hourly Values

This section describes the World Data Centre format for observatory hourly mean values. Magnetic data are organized in 1-year files, with the information coded in ASCII.

    COLUMNS   FORMAT   DESCRIPTION

    1-3       A3       Observatory 3-letter code
    4-5       I2       Year. Last 2 digits, 1996 = 96. See also columns 15-16.
    6-7       I2       Month (01-12)
    8         Al       Element (D,I,H,X,Y,Z, or F)
    9-10      I2       Day of month (01-31)
    11-12     A2       Blanks
    13        A1       Arbitrary
    14        A1       Arbitrary                              *== OLD FORMAT ==========================*
    15-16     I2       Century digits                         | Column 15: INTERNATIONAL QUIET         |
                       Year = 1889, Century digits = 18       |            or DISTURBED DAYS Q=1, D=2  |
                       Year = 1996, Century digits = 19       | Column 16: Blank for data since 1900,  |
                       Year = 2014, Century digits = 20       |            8 for data before.          |
    17-20     I4       Tabular base.                          *========================================*
                       The values are in degrees for D and I, and in
                       hundreds of nanoTeslas for the intensity elements.
    21-116    24I4     24 4-digit hourly mean values for the day.
                       The values are in tenth-minutes for D and I, and in
                       nanoTeslas for the intensity elements.
                       The first hourly mean value represents the mean value
                       between 00:00 UT and 01:00 UT, ..., the 24th value
                       represents the mean between 23:00 UT and 24:00 UT.
                       A missing value is identified by 9999.
    117-120   I4       Daily Mean.
                       If any of the hourly mean values for the day are missing
                       9999 will appear as the daily mean.
    121-122            Record end marker.
                       Two chars 'cr'= 13 and 'nl'= 10.

- The tabular bases, hourly mean values and daily means are right adjusted and signed if negative.
- Negative values are identified with a minus sign either adjacent to the first significant digit or in the high-order position of the field. NOTE: A blank digit will not appear between a (-) sign and the first significant digit. For example, a value may appear as -050 or b-50 but not as -b50 (b=blank).
- The 25 values in positions 21-120 will have the range -999 to 9998, with 9999 reserved for missing values.
- The records are sorted according to observatory code, year, month, element, day (positions 1-10).
- For the intensity elements hourly value (nanoTeslas) = tab.base*100 + tab.value
- For the angles D and I hourly value (Degrees) = tab.base + tab.value/600

## Minute Values

This section describes the World Data Centre format for observatory minute mean values. Magnetic data are organized in 1-month files, with the information coded in ASCII.

    COLUMNS   FORMAT   DESCRIPTION

    1-6       I6       Observatory's North Polar distance.
                       0ø to 180ø from the north geographic pole in thousandths
                       of a degree. Decimal point is implied between positions 3
                       and 4.
    7-12      I6       Observatory's Geographic longitude.
                       0ø to 360ø measured east from Greenwich in thousandths
                       of a degree. Decimal point is implied between positions 9
                       and 10.
    13-14     I2       Year. Last 2 digits, 1996 = 96. See also column 26.
    15-16     I2       Month (01-12)
    17-18     I2       Day of month (01-31)
    19        Al       Element (D,I,H,X,Y,Z, or F)
    20-21     I2       Hour of day (00-23)
    22-24     A3       Observatory 3-letter code.          *== OLD FORMAT =====================*
    25        A1       Arbitrary.                          | Column 25: Origin of data         |
    26        I1       Century digit.                      |            D=digital, A=digitized |
                       Year = 2014, Century digit = 0.     | Columns 26 - 34: Not used.        |
                       Year = 1889, Century digit = 8.     *===================================*
                       Year = 1996, Century digit = 9 or 'SPACE' for backwards
                       compatibility.
    27        A1       Preliminary or Definitive data.
                       Preliminary = P , Definitive = D
    28-34     A7       Blanks
    35-394    60I6     60 6-digit 1-minute values for the given element for that
                       data hour.
                       The values are in tenth-minutes for D and I, and in
                       nanoTeslas for the intensity elements.
    395-400   I6       Hourly Mean.
                       The average of the preceeding 60 1-minute values.
    401-402            Record end marker.
                       Two chars 'cr'= 13 and 'nl'= 10.

- Each element value and the hourly mean is given in a 6-digit field including a minus sign for negative values.
- Missing data value spaces are padded with 999999.
- The records are sorted according to observatory code, year, month, day, element.

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