Archive Data Formats

INTERMAGNET Archive Format : IAF

IAFV2.11 Binary Data Structure Format-32 Bit Words

Section

Word

Field Name

Comment

Header

1

Station ID

eg: BOU = HEX(20 42 4F 55)

2

Year and day number

eg: 1989001; year 1989, day January 01

3

Co-latitude

(90° - Latitude) * 1000, to WGS-84 datum

4

Longitude

East Longitude * 1000, to WGS-84 datum

5

Elevation

elevation in meters above sea level, to WGS-84 datum

6

Orientation

eg: XYZG = HEX(58 59 5A 47); HDZG = HEX(48 44 5A 47); XYZ = HEX(20 58 59 5A); and HDZ = HEX(20 48 44 5A)

7

Source

eg: DMI = HEX(20 44 4D 49)

8

D conversion

H/3438*10000 where H=annual mean of H (set to 10000 for XYZG)

9

Data Quality

IMAG = HEX (49 4D 41 47)

10

Instrumentation

eg: LC(Linear Core) = HEX(20 20 4C 43) (or RC(Ring Core))

11

K9 value in nT

eg: 750

12

Sampling rate (ms)

eg: 125

13

Sensor orientation

eg: XYZF, DIF, UVZ, HDZ, HDZF etc.

14

Publication Date

eg: YYMM = 0806 (June 2008) HEX (30 38 30 36)

15

IAF version number and data type

HEX(04 tt 00 00) version 2.11 and tt is data type flag (00 = definitive, 01 = quasi-definitive)

16

Reserved for future use

One minute data

17

1440 mean minute values - element 1 (one day)

Missing value = 999999

1440 mean minute values - element 2 (one day)

Missing value = 999999

1440 mean minute values - element 3 (one day)

Missing value = 999999

5776

1440 mean minute values - element 4 (one day)

Missing value = 999999

Scalar not recorded = 888888

Mean hourly data

5777

24 mean hourly values - element 1

Missing value = 999999

24 mean hourly values - element 2

Missing value = 999999

24 mean hourly values - element 3

Missing value = 999999

5872

24 mean hourly values - element 4

Missing value = 999999

Daily means

5873

daily mean value element 1

Missing value = 999999

5874

daily mean value element 2

Missing value = 999999

5875

daily mean value element 3

Missing value = 999999

5876

daily mean value element 4

Missing value = 999999

K indices

5877

8 K-values

Missing value = 999

Reserved

5885 - 5888

Reserved for each contributing institution

See Section 6.4.3.2.1 for details.

IAFV2.10 Binary Data Structure Format-32 Bit Words

Section

Word

Field Name

Comment

Header

1

Station ID

eg: BOU = HEX(20 42 4F 55)

2

Year and day number

eg: 1989001; year 1989, day January 01

3

Co-latitude

(90° - Latitude) * 1000, to WGS-84 datum

4

Longitude

East Longitude * 1000, to WGS-84 datum

5

Elevation

elevation in meters above sea level, to WGS-84 datum

6

Orientation

eg: XYZG = HEX(58 59 5A 47); HDZG = HEX(48 44 5A 47); XYZ = HEX(20 58 59 5A); and HDZ = HEX(20 48 44 5A)

7

Source

eg: DMI = HEX(20 44 4D 49)

8

D conversion

H/3438*10000 where H=annual mean of H (set to 10000 for XYZG)

9

Data Quality

IMAG = HEX (49 4D 41 47)

10

Instrumentation

eg: LC(Linear Core) = HEX(20 20 4C 43) (or RC(Ring Core))

11

K9 value in nT

eg: 750

12

Sampling rate (ms)

eg: 125

13

Sensor orientation

eg: XYZF, DIF, UVZ, HDZ, HDZF etc.

14

Publication Date

eg: YYMM = 0806 (June 2008) HEX (30 38 30 36)

15

IAF version number

HEX(03 00 00 00) version 2.10

16

Reserved for future use

One minute data

17

1440 mean minute values - element 1 (one day)

Missing value = 999999

1440 mean minute values - element 2 (one day)

Missing value = 999999

1440 mean minute values - element 3 (one day)

Missing value = 999999

5776

1440 mean minute values - element 4 (one day)

Missing value = 999999

Scalar not recorded = 888888

Mean hourly data

5777

24 mean hourly values - element 1

Missing value = 999999

24 mean hourly values - element 2

Missing value = 999999

24 mean hourly values - element 3

Missing value = 999999

5872

24 mean hourly values - element 4

Missing value = 999999

Daily means

5873

daily mean value element 1

Missing value = 999999

5874

daily mean value element 2

Missing value = 999999

5875

daily mean value element 3

Missing value = 999999

5876

daily mean value element 4

Missing value = 999999

K indices

5877

8 K-values

Missing value = 999

Reserved

5885 - 5888

Reserved for each contributing institution

IAFV2.10 (2010 to 2013)

Words 1 to 16 comprise the header section containing a mixture of text and numeric fields, including a 3-letter observatory identification preceded with a space [hex20] (ID) code, the year concatenated with the day of the year, co-latitude, longitude, elevation, reported orientation, originating organization, a D-conversion factor, data quality, instrumentation, K-9, sampling rate, sensor orientation, publication date and format version/data type. Latitude, longitude/colatitude and elevation must be given using the WGS-84 datum. From 2010 onward, the orientation codes “XYZ” and “HDZ” have been added to “XYZG” and “HDZG” where “G” represents ΔF (see description below). These new codes indicate that the observatory is recording 3 elements only (no scalar instrument). The D-conversion factor is a fixed value used only in the graphics portion of the access software to allow Declination to be plotted in minutes of arc and equivalent nanoteslas (nT). It is given as H/3438*10000, where H is the annual mean value of the horizontal intensity. Example: If H is 16500 D will be 47993(Integer). When XYZG or XYZ is used, the D-conversion factor should be set to 10000.

ASCII values, such as the observatory ID and orientation, are also stored as 32-bit words, but are coded as the hexadecimal byte-string corresponding to the ASCII string. For example, the string “HDZF” is coded as the sequence “48 44 5A 46”. Where a string is shorter than four bytes, it is padded to the left with spaces. For example, the string “ESK” is coded as the sequence “20 45 53 4B”.

Word 11 is the K-9 value for the observatory in nT, word 12 is the digital sampling rate in msec, and word 13 is the sensor orientation. Sensor orientation could be XYZF, DIF, UVZ, HDZ, HDZF etc. and should indicates which components are actually measured. If a three component sensor orientation is used, a space must be added to the left. Word 14 is the publication date encoded as 4 ASCII bytes “YYMM” provided by INTERMAGNET. The high byte (left most) of word 15 is the INTERMAGNET Archive Format version number code provided by the IMO. It takes the form of a binary single byte number ranging from 0 to 255. Zero (0x00) represents version 1.00, one (0x01) represents version 1.10, two (0x02) represents version 2.00 and three (0x03) represents version 2.10. The other three bytes of word 15 are reserved for future use and padded with zeros. Word 16 is reserved for future use.

Words 17-5776 contain the minute values of the 4 geomagnetic elements (successively X,Y,Z,G or H,D,Z,G or X,Y,Z, or H,D,Z ) for the day. From 2009 onward, the 4th element contains the difference between the square root of the sum of the squares of the variometer components, F(v), and the total field from an independent scalar recording, F(s). This difference, ΔF, is defined as F(v) - F(s). Both F(v) and F(s) must be corrected to the location in the observatory where absolute geomagnetic observations are made. When F(s) is missing or both F(s) and F(v) are missing, ΔF must be set to 999999. When F(v) only is missing, ΔF must be set to -F(s). The values of the 4 elements are stored in tenth-units with an implied decimal point. Thus, an H value of 21305.6 is stored (in tenth-nT) as 213056 with a decimal point implied between the last and next-to-last digits. Words 5777-5872 are used for the hourly mean values of the successive 4 elements. From 2009 onward, words 5849-5872 always record 999999 (missing value), this is done because the 4th element in the data is a quality check for minute mean data and this quality check is meaningless for hourly means. Words 5873-5876 store the 4 daily mean values. From 2009 onward, word 5876 always record 999999 (missing value) because the quality check for daily means is also meaningless. From 2009 onward, the last 4 words (5885-5888) are available for each contributing institution. Missing data for minute, hour, and day values are stored as “999999”. From 2010 onward, if a scalar instrument is not used (so no data is recorded in the fourth element) the value “888888” should be used instead of “999999”. Missing K-Index values are stored as “999”.

IAFV2.00 Binary Data Structure Format-32 Bit Words

Section

Word

Field Name

Comment

Header

1

Station ID

eg: BOU = HEX(20 42 4F 55)

2

Year and day number

eg: 1989001; year 1989, day January 01

3

Co-latitude

(90° - Latitude) * 1000, to WGS-84 datum

4

Longitude

East Longitude * 1000, to WGS-84 datum

5

Elevation

elevation in meters above sea level, to WGS-84 datum

6

Orientation

eg: XYZG = HEX(58 59 5A 47); and HDZG = HEX(48 44 5A 47)

7

Source

eg: DMI = HEX(20 44 4D 49)

8

D conversion

H/3438*10000 where H=annual mean of H (set to 10000 for XYZG)

9

Data Quality

IMAG = HEX (49 4D 41 47)

10

Instrumentation

eg: LC(Linear Core) = HEX(20 20 4C 43) (or RC(Ring Core))

11

K9 value in nT

eg: 750

12

Sampling rate (ms)

eg: 125

13

Sensor orientation

eg: XYZF, DIF, UVZ, HDZ, HDZF etc.

14

Publication Date

eg: YYMM = 0806 (June 2008) HEX (30 38 30 36)

15

IAF version number

HEX(02 00 00 00) version 2.00

16

Reserved for future use

One minute data

17

1440 mean minute values - element 1 (one day)

Missing value = 999999

1440 mean minute values - element 2 (one day)

Missing value = 999999

1440 mean minute values - element 3 (one day)

Missing value = 999999

5776

1440 mean minute values - element 4 (one day)

Missing value = 999999

Mean hourly data

5777

24 mean hourly values - element 1

Missing value = 999999

values - element 2

999999

24 mean hourly values - element 3

Missing value = 999999

5872

24 mean hourly values - element 4

Missing value = 999999

Daily means

5873

daily mean value element 1

Missing value = 999999

5874

daily mean value element 2

Missing value = 999999

5875

daily mean value element 3

Missing value = 999999

5876

daily mean value element 4

Missing value = 999999

K indices

5877

8 K-values

Missing value = 999

Reserved

5885 - 5888

Reserved for each contributing institution

IAFV2.00 (2009)

Words 1 to 16 comprise the header section containing a mixture of text and numeric fields, including a 3-letter observatory identification preceded with a space [hex20] (ID) code, the year concatenated with the day of the year, co-latitude, longitude, elevation, reported orientation, originating organization, a D-conversion factor, data quality, instrumentation, K-9, sampling rate, sensor orientation, publication date and format version/data type. Latitude, longitude/colatitude and elevation must be given using the WGS-84 datum. From 2009 onward, the orientation must be “XYZG” or “HDZG” where “G” represents ΔF (see description below). The D-conversion factor is a fixed value used only in the graphics portion of the access software to allow Declination to be plotted in minutes of arc and equivalent nanoteslas (nT). It is given as H/3438*10000, where H is the annual mean value of the horizontal intensity. Example: If H is 16500 D will be 47993(Integer). When XYZG is used, the D-conversion factor should be set to 10000.

ASCII values, such as the observatory ID and orientation, are also stored as 32-bit words, but are coded as the hexadecimal byte-string corresponding to the ASCII string. For example, the string “HDZF” is coded as the sequence “48 44 5A 46”. Where a string is shorter than four bytes, it is padded to the left with spaces. For example, the string “ESK” is coded as the sequence “20 45 53 4B”.

Word 11 is the K-9 value for the observatory in nT, word 12 is the digital sampling rate in msec, and word 13 is the sensor orientation. Sensor orientation could be XYZF, DIF, UVZ, HDZ, HDZF etc. and should indicates which components are actually measured. If a three component sensor orientation is used, a space must be added to the left. Word 14 is the publication date encoded as 4 ASCII bytes “YYMM” provided by INTERMAGNET. The high byte (left most) of word 15 is the INTERMAGNET Archive Format version number code provided by INTERMAGNET. It takes the form of a binary single byte number ranging from 0 to 255. Zero (0x00) represents version 1.00, one (0x01) represents version 1.10 and two (0x02) represents version 2.00. The other three bytes of word 15 are reserved for future use and padded with zeros. Word 16 is reserved for future use.

Words 17-5776 contain the minute values of the 4 geomagnetic elements (successively X,Y,Z,G or H,D,Z,G ) for the day. From 2009 onward, the 4th element contains the difference between the square root of the sum of the squares of the variometer components, F(v), and the total field from an independent scalar recording, F(s). This difference, ΔF, is defined as F(v) - F(s). Both F(v) and F(s) must be corrected to the location in the observatory where absolute geomagnetic observations are made. When F(s) is missing or both F(s) and F(v) are missing, ΔF must be set to 999999. When F(v) only is missing, ΔF must be set to -F(s). The values of the 4 elements are stored in tenth-units with an implied decimal point. Thus, an H value of 21305.6 is stored (in tenth-nT) as 213056 with a decimal point implied between the last and next-to-last digits. Words 5777-5872 are used for the hourly mean values of the successive 4 elements. From 2009 onward, words 5849-5872 always record 999999 (missing value), this is done because the 4th element in the data is a quality check for minute mean data and this quality check is meaningless for hourly means. Words 5873-5876 store the 4 daily mean values. From 2009 onward, word 5876 always record 999999 (missing value) because the quality check for daily means is also meaningless. From 2009 onward, the last 4 words (5885-5888) are available for each contributing institution. Missing data for minute, hour, and day values are stored as “999999”. Missing K-Index values are stored as “999”.

IAFV1.10 Binary Data Structure Format-32 Bit Words

Section

Word

Field Name

Comment

Header

1

Station ID

eg: BOU = HEX(20 42 4F 55)

2

Year and day number

eg: 1989001; year 1989, day January 01

3

Co-latitude

(90° - Latitude) * 1000, to WGS-84 datum

4

Longitude

East Longitude * 1000, to WGS-84 datum

5

Elevation

elevation in meters above sea level, to WGS-84 datum

6

Orientation

eg: XYZF = HEX(58 59 5A 46); and HDZF = HEX(48 44 5A 46)

7

Source

eg: DMI = HEX(20 44 4D 49)

8

D conversion

H/3438*10000 where H=annual mean of H (set to 10000 for XYZF)

9

Data Quality

IMAG = HEX (49 4D 41 47)

10

Instrumentation

eg: LC(Linear Core) = HEX(20 20 4C 43) (or RC(Ring Core))

11

K9 value in nT

eg: 750

12

Sampling rate (ms)

eg: 125

13

Sensor orientation

eg: XYZF, DIF, UVZ, HDZ, HDZF etc.

14

Publication Date

eg: YYMM = 0806 (June 2008) HEX (30 38 30 36)

15

IAF version number

HEX(01 00 00 00) IAFV1.10

16

Reserved for future use

One minute data

17

1440 mean minute values - element 1 (one day)

Missing value = 999999

1440 mean minute values - element 2 (one day)

Missing value = 999999

1440 mean minute values - element 3 (one day)

Missing value = 999999

5776

1440 mean minute values - element 4 (one day)

Missing value = 999999

Mean hourly data

5777

24 mean hourly values - element 1

Missing value = 999999

24 mean hourly values - element 2

Missing value = 999999

24 mean hourly values - element 3

Missing value = 999999

5872

24 mean hourly values - element 4

Missing value = 999999

Daily means

5873

daily mean value element 1

Missing value = 999999

5874

daily mean value element 2

Missing value = 999999

5875

daily mean value element 3

Missing value = 999999

5876

daily mean value element 4

Missing value = 999999

K indices

5877

8 digitally derived K-values

Missing value = 999

Reserved

5885 - 5888

Reserved for future use = 0

IAFV1.10 (2008)

Words 1 to 16 comprise the header section containing a mixture of text and numeric fields, including a 3-letter observatory identification preceded with a space [hex20] (ID) code, the year concatenated with the day of the year, co-latitude, longitude, elevation, reported orientation, originating organization, a D-conversion factor, data quality, instrumentation, K-9, sampling rate, sensor orientation, publication date and format version/data type. Latitude, longitude/colatitude and elevation must be given using the WGS-84 datum. The orientation must be “XYZF” or “HDZF”. If the F element is not measured, it must be filled with 999999 in the data section. The D-conversion factor is a fixed value used only in the graphics portion of the access software to allow Declination to be plotted in minutes of arc and equivalent nanoteslas (nT). It is given as H/3438*10000, where H is the annual mean value of the horizontal intensity. Example: If H is 16500 D will be 47993(Integer). When XYZF is used, the D-conversion factor should be set to 10000.

ASCII values, such as the observatory ID and orientation, are also stored as 32-bit words, but are coded as the hexadecimal byte-string corresponding to the ASCII string. For example, the string “HDZF” is coded as the sequence “48 44 5A 46”.

Word 11 is the K-9 value for the observatory in nT, word 12 is the digital sampling rate in msec, and word 13 is the sensor orientation. Sensor orientation could be XYZF, DIF, UVZ, HDZ, HDZF etc. and should indicates which components are actually measured. If a three component sensor orientation is used, a space must be added at the end. Word 14 is the publication date encoded as 4 ASCII bytes “YYMM” provided by INTERMAGNET. The high byte (left most) of word 15 is the INTERMAGNET Archive Format version number code provided by INTERMAGNET. It takes the form of a binary single byte number ranging from 0 to 255. Zero (0x00) represents version 1.00 and one (0x01) represents version 1.10. The other three bytes of word 15 are reserved for future use and padded with zeros. Word 16 is reserved for future use.

Words 17-5776 contain the minute values of the 4 components (successively X,Y,Z,F or H,D,Z,F) for the day. The 4th component “F” should be included only if it is measured from a scalar instrument independent of the other 3 components otherwise it must be filled with 999999. The values of the 4 components are stored in tenth-units with an implied decimal point. Thus, an H value of 21305.6 is stored (in tenth-nT) as 213056 with a decimal point implied between the last and next-to-last digits and a D value of 527.6 is stored (in tenth-minutes) as 5276 also with a decimal point implied between the last and next-to-last digits. Words 5777-5872 are used for the hourly mean values of the successive 4 components. Words 5873-5876 store the 4 daily mean values. Words 5877-5884 contain the K-Index*10. The last 4 words (5885-5888) are reserved for future use and padded with zeros. Missing data for minute, hour, and day values are stored as “999999”. Missing K-Index and Ak values are stored as “999”.

IAFV1.00 Binary Data Structure Format-32 Bit Words

Section

Word

Field Name

Comment

Header

1

Station ID

eg: BOU = HEX(20 42 4F 55)

2

Year and day number

eg: 1989001; year 1989, day January 01

3

Co-latitude

(90° - Latitude) * 1000, to WGS-84 datum

4

Longitude

East Longitude * 1000, to WGS-84 datum

5

Elevation

elevation in meters above sea level, to WGS-84 datum

6

Orientation

eg: XYZF = HEX(58 59 5A 46); and HDZF = HEX(48 44 5A 46)

7

Source

eg: DMI = HEX(20 44 4D 49)

8

D conversion

H/3438*10000 where H=annual mean of H

9

Data Quality

IMAG = HEX (49 4D 41 47)

10

Instrumentation

eg: LC(Linear Core) = HEX(20 20 4C 43) (or RC(Ring Core))

11

K9 value in nT

eg: 750

12

Sampling rate (ms)

eg: 125

13

Sensor orientation

eg: XYZF, DIF, UVZ, HDZ, HDZF etc.

14

Reserved for future use

15

IAF version number

HEX(00 00 00 00) IAFV1.00

16

Reserved for each contributing institution

One minute data

17

1440 mean minute values - element 1 (one day)

Missing value = 999999

1440 mean minute values - element 2 (one day)

Missing value = 999999

1440 mean minute values - element 3 (one day)

Missing value = 999999

5776

1440 mean minute values - element 4 (one day)

Missing value = 999999

Mean hourly data

5777

24 mean hourly values - element 1

Missing value = 999999

24 mean hourly values - element 2

Missing value = 999999

24 mean hourly values - element 3

Missing value = 999999

5872

24 mean hourly values - element 4

Missing value = 999999

Daily means

5873

daily mean value element 1

Missing value = 999999

5874

daily mean value element 2

Missing value = 999999

5875

daily mean value element 3

Missing value = 999999

5876

daily mean value element 4

Missing value = 999999

K indices

5877

8 digitally derived K-values

Missing value = 999

Reserved

5885 - 5888

Reserved for future use = 0

see Section 6.4.3.2 for details on word 5885

IAFV1.00 (2007 and before)

Words 1 to 16 comprise the header section containing a mixture of text and numeric fields, including a 3-letter observatory identification preceded with a space [hex20] (ID) code, the year concatenated with the day of the year, co-latitude, longitude, elevation, reported orientation, originating organization, a D-conversion factor, data quality, instrumentation, K-9, sampling rate and sensor orientation. Latitude, longitude/colatitude and elevation must be given using the WGS-84 datum. From 1991 to 2005, the fourth component is the total field from either a scalar (independent) instrument or the total field calculated from the main observatory instrument. INTERMAGNET has a list of which observatories supplied which type of total field value between 1991 and 2005 and this list is available as a spreadsheet in the archive viewer software. The D-conversion factor is a fixed value used only in the graphics portion of the access software to allow Declination to be plotted in minutes of arc and equivalent nanoteslas (nT). It is given as H/3438*10000, where H is the annual mean value of the horizontal intensity. Example: If H is 16500 D will be 47993(Integer). This conversion factor only applies to HDZ observatory data supplied before 2005.

ASCII values, such as the observatory ID and orientation, are also stored as 32-bit words, but are coded as the hexadecimal byte-string corresponding to the ASCII string. For example, the string “HDZF” is coded as the sequence “48 44 5A 46”.

Word 11 is the K-9 value for the observatory in nT, word 12 is the digital sampling rate in msec, and word 13 is the sensor orientation. Sensor orientation could be XYZF, DIF, UVZ, HDZ, HDZF etc. and should indicates which components are actually measured. If a three component sensor orientation is used, a space must be added at the end. Word 14-15 are reserved for future use and padded with zeros. In version 1.10 and later, word 15 have been defined to represent the version number. Previously, it should have been coded to zero by IMOs, that is the reason this word was chosen for the version number (zero represents version 1.00). Word 16 is set aside for each contributing institution to use as they wish, provided it is coded as a 32-bit binary value.

Words 17-5776 contain the minute values of the 4 components (successively X,Y,Z,F or H,D,Z,F) for the day. Until 2005, the 4th component could contain “F” from either a scalar or calculated from the vector instrument. From 2006 onward, the 4th component contains “F” only if it is measured from a scalar instrument independent of the other 3 components otherwise it must be filled with 999999. The values of the 4 components are stored in tenth-units with an implied decimal point. Thus, an H value of 21305.6 is stored (in tenth-nT) as 213056 with a decimal point implied between the last and next-to-last digits and a D value of 527.6 is stored (in tenth-minutes) as 5276 also* with a decimal point implied between the last and nextto- last digits. Words 5777-5872 are used for the hourly mean values of the successive 4 components. Words 5873-5876 store the 4 daily mean values. Prior to the 1994 CD-ROM, words 5877-5884 held the 8 (K-Index*10) values for the day. The true IAGA K-Index could be obtained from these K-Index*10 values by truncating the second (least significant) digit. From 1994 onward, words 5877-5884 contain the K-Index*10. Until 1998, word 5885 contained the equivalent daily amplitude index (Ak). From 1999 onward, word 5885 is reserved for future use and padded with zeros. The last 3 words (5886-5888) are reserved for future use and padded with zeros. Missing data for minute, hour, and day values are stored as “999999”. Missing K-Index and Ak values are stored as “999”.

INTERMAGNET Physical Media Directory Structure

The structure of files and folders on the INTERMAGNET Physical Media (IPM) has remained broadly the same since its inception in 1991, however there have been some differences. This appendix documents the structure for the USB (2014), then describes the structure of the DVD (2011) and the first CD-ROM (1991) and lists year by year differences in the files and folders on the INTERMAGNET Physical Media (IPM).

Structure of the USB (2014)

.
├── errata
│    └── errata.txt
├── mag2014
│   ├── 2014maps
│   │    ├── alg.png
│   │    ├── all.png
│   │    ├── aus.png
│   │    ├── ...
│   │
│   ├── ctry_inf
│   │   ├── algsrn.png
│   │   ├── aussrn.png
│   │   ├── ...
│   │   ├── readme.alg
│   │   ├── readme.arg
│   │   ├── ...
│   │
│   ├── aaa
│   │   ├── aaa14jan.bin
│   │   ├── aaa14feb.bin
│   │   ├── ...
│   │   ├── aaa14k.dka
│   │   ├── aaa2014.blv
│   │   ├── readme.aaa
│   │   └── yearmean.aaa
│   ├── ...
│   └──obsy_inf
├── imcdview_install.txt
├── readme.txt
└── software
    └── Disk1
        └── InstData
            ├── GenericUnix
            │   └──  IMCDView.bin
            ├── Linux_32
            │   │── NoVM
            │   │   └── IMCDView.bin
            │   └── VM
            │       └── IMCDView.bin
            ├── Linux_64
            │   │── NoVM
            │   │   └── IMCDView.bin
            │   └── VM
            │       └── IMCDView.bin
            ├── MacOSX
            │   │── NoVM
            │   │   └── IMCDView.bin
            │   └── VM
            │       └── IMCDView.bin
            ├── Solaris
            │   │── NoVM
            │   │   └── IMCDView.bin
            │   └── VM
            │       └── IMCDView.bin
            ├── Unix_with_VM
            │   └── VM
            │       └── IMCDView.bin
            ├── Windows_32_or_64_bit
            │   │── NoVM
            │   │   └── IMCDView.exe
            │   └── VM
            │       └── IMCDView.exe
            ├── Windows_Pure_64_bit
            │   │── NoVM
            │   │   └── IMCDView.exe
            │   └── VM
            │       └── IMCDView.exe
            ├── MediaId.properties
            └── Resource1.zip

Structure of (2011) DVD

.
├── errata
│     └── errata.txt
├── mag2011
│   ├── 2011maps
│   │   ├── alg.png
│   │   ├── all.png
│   │   ├── aus.png
│   │   ├── ...
│   │
│   ├── ctry_inf
│   │   ├── algsrn.png
│   │   ├── aussrn.png
│   │   ├── ...
│   │   ├── readme.alg
│   │   ├── readme.all
│   │   ├── ...
│   ├── aaa
│   │   ├── aaa11jan.bin
│   │   ├── aaa11feb.bin
│   │   ├── ...
│   │   ├── aaa2011.blv
│   │   ├── aaa11k.dka
│   │   ├── readme.aaa
│   │   └── yearmean.aaa
│   ├── aae
│   │   ├── aae11jan.bin
│   │   ├── aae11feb.bin
│   │   ├── ...
│   │   ├── aae2011.blv
│   │   ├── aae11k.dka
│   │   ├── readme.aae
│   │   └── yearmean.aae
│   ├── ...
│   │
│   └── obsy_inf
├── imcdview_install.txt
├── readme.txt
└── software
    └── Disk1
        └── InstData
            ├── Linux
            │   └── NoVM
            │       └── IMCDView.bin
            ├── Mac
            │   └── NoVM
            │       └── IMCDView.app
            ├── MediaId.properties
            ├── Resource1.zip
            ├── Solaris
            │   └── NoVM
            │       └── IMCDView.bin
            └── Windows
                └── NoVM
                    └── IMCDView.exe

Structure of first (1991) CD-ROM

├── MAG1991
│   ├── 1991MAPS
│   │   ├── ALL.png
│   │   ├── AUS.png
│   │   ├── CAN.png
│   │   ├── ...
│   ├── CTRY_INF
│   │   ├── CTRYLIST.IDX
│   │   ├── ALLSRN.PCX
│   │   ├── AUSSRN.PCX
│   │   ├── README.ALL
│   │   ├── README.AUS
│   │   ├── ...
│   └── OBSY_INF
│       └── 91OBSDAT.DBF
├── AMS
│   ├── AMS91JAN.BIN
│   ├── MAS91FEB.BIN
│   ├── ...
│   ├── AMS91K.DKA
│   └── README.AMS
├── XTRAS
│   ├── PRNSTRUC.EXE
│   └── STRUCTUR.DAT
├── README.TXT
└── README.EXE

INTERMAGNET Physical Media Directory Structure

The files on the INTERMAGNET Physical Media are set up in a particular directory structure. The root directory contains a “README.TXT” file, which is an ASCII file describing the INTERMAGNET Physical Media and where to obtain information about it, the software, and documentation; CD-ROMs from 1991-2004 also hold a “README.EXE” file, which is an executable version of the README.TXT file that allows the user to scroll back and forth through the information. DVDs and USBs do not contain README.EXE.

On the 1991 CD-ROM there are also two sub-directories. One is labelled “XTRAS”, and the other “MAG1991”. The XTRAS directory contains one file labeled “STRUCTUR.DAT”, and another “PRNSTRUC.EXE”. The STRUCTUR.DAT file provides a schematic of the data structure for the records on the CD-ROM and the PRNSTRUC.EXE file enables the user to obtain a printout of that record structure.

The MAG1991 directory contains a sub-directory for each observatory identified by its 3-letter ID code. In addition, there are sub-directories labeled “1991MAPS”, “CTRY_INF”, and “OBSY_INF”. The 1991MAPS directory contains the *.PCX files that are the map images of each country for use in the access software. These are labeled by a 3-letter country ID with the PCX extension, and one labeled “ALL.PCX” for the “All Countries” option. The CTRY_INF directory contains a “CTRYLIST.IDX” file that is used internally, *.PCX files for each country (and one for ALL) that are the images used to show the flag and organizational Logo for the different countries, and the README files that pertain to each country’s geomagnetism program (including a README for the ALL option). The OBSY_INF subdirectory contains a “91OBSYDAT.DBF” file that is used internally in the software. Since 2006 .pcx and .gif graphic fiels have been replaced with .png files. It concerns both maps in YYYYMAPS and About-screen images in CTRY_INF, where YYYY is the 4-character year value.

The individual sub-directories (e.g. BFE for Brorfelde, TUC for Tucson, etc.) contain the 12 months of data labeled with the 3-letter ID, 2-character year, 3-letter month abbreviation, and a “BIN” extension indicating they are binary files. For example, “BFE91AUG.BIN” is a file of 31 sequential day-records for Brorfelde, for 1991, for August. In addition, there are the “README.XXX” files for the individual observatory, where the XXX indicates the 3-letter observatory ID.

This sub-directory may also contain a file labeled as XXXYRK.DKA, where the XXX is the 3-letter observatory ID, the YR is the 2-character year value and the K indicates a K-Index file. Originally the DKA extension was used to indicate that the data were generated from a digital algorithm in an ASCII format, however subsequently these files have been used to hold both digitally derived and hand-scaled K indices. Since 2005 the DKA files have been created by INTERMAGNET, using data from the binary IAF file (before 2005 these files were provided by the observatories). The consequence is that DKA ASCII files provided by IMOs are ignored during final compilation of INTERMAGNET Physical Media. These ASCII K-Index files are published on, even though the data are in the binary records, because they are much faster to access than paging through the binary records on the INTERMAGNET Physical Media.

List of Changes to the Structure since the first (1991) CD-ROM

Year

Change

1992

No change

1993

No change

1994

First CD-ROM with an ERRATA folder in the root of the disk IMAG21.EXE and INSTALL.EXE added to the root of the CD-ROM

1995

Annual means included in a YEARMEAN.obs file in each observatory folder

1996

IMAG22.EXE replaces IMAG21.EXE

PLOTUTIL folder added to the root of the CD-ROM containing plotting source code and executables (for DOS)

1997

No change

1998

Republication of some data (folders in root of CD-ROM):

  • CLF 1996

  • PPT, THY 1991

1999

No change

2000

1st year of distribution on 2 CD-ROMs (the number of observatories meant that the data was too large to fit on a single CD-ROM) IMAG23.EXE replaces IMAG22.EXE

INTRO00A.PCX and INTRO00B.PCX are include in CTRY_INF folder – these are splash screens for individual disks

2001

Republication of some data (folders in root of 1st CD-ROM only):

  • ABG 2000

Removed INTRO00A.PCX and INTRO00B.PCX from CTRY_INF

2002

IMAG24.EXE replaces IMAG23.EXE

Republication of some data (folders in root of both CD-ROMs):

  • TAN 2001

INTRO1.PCX and INTRO2.PCX are included in CTRY_INF folder

2003

Republication of some data (folders in root of both CD-ROMs):

  • FRN, HON 1993

  • HON 2001, 2002

  • PPT 2002

2004

Republication of some data (folders in root of both CD-ROMs):

  • 2003 ABG, IQA, SJG

A new UTILITY folder is put into the root of the CD-ROM. It holds software for working with the data, including the first distributed version (V1.1) of the imcdview viewing software in CDVIEWER/CDVIEWER.JAR V1.1

The OBSY_INF folder includes a file OBS_V101.CSV – a list of observatories used by imcdview

2005

Republication of some data (folders in root of both CDs):

  • 2003 NVS

  • 2004 WNG

Filenames on the CD-ROMs are now in lowercase (this documentation will continue to show filename in uppercase for clarity)

GIF files are used for some graphics files (alongside PCX)

The UTILITY folder is removed A SOFTWARE folder is added to the root of the CD-ROM. It contains the CD viewer software, imcdview.jar V1.2 and associated installer software

An AUTORUN.INF file is added to the root of the CD-ROM to run the imcdview installer when the disk is inserted (only works on Windows operating systems)

The following files are removed from the CTRY_INF folder: INTRO.PCX, INTRO1.PCX, INTRO2.PCX, CTRYLIST.IDX The OBSY_INFO folder is retained, but is empty

The IMAG24.EXE viewing software and its associated files are removed from the root of the disk

The XTRAS folder is removed

2006

Publication moves from two CD-ROMs to a single DVD

All graphics files are in PNG format

The root of the DVD contains the following folders and files:

  • AUTORUN.INF

  • ERRATA

  • MAG2006

  • README.TXT

  • SOFTWARE

The software folder contains the imcdview visualisation software along with a simple installer

2007

A multi-OS “Install Anywhere” installer is included for the imcdview visualisation software.

A Java Virtual Machine is no longer required to run the software, as this is include on the DVD

2008

No change

2009

A major republication of data from years 2005, 2006, 2007 and 2008

The AUTORUN.INF file is removed from the root of the DVD

The IMCDVIEW_INSTALL.TXT file is added to the root of the DVD

2010

No change

2011

Publication physical maps instead of political country maps

2012

No change

2013

No change

2014

Publication moves from DVD to USB drive

2015

Final physical publication including all data from 1991 to 2015

Note

Unless otherwise noted, where a change is shown in the structure, the change affects all years subsequent to the year where the change is described. The exception to this is republished data.

Republished data is put into a folder at the root of the INTERMAGNET Physical Media. It is only put on for one year – the republished data is not repeated on subsequent INTERMAGNET Physical Medias. Because the data is not under the MAGyyyy folder, it will not be recognised by the imcdview viewing software (where a number of years where republished in a form that the software can access).

The OBSY_INF folder is present on all INTERMAGNET Physical Medias, though it may be empty. It is used by software (along with the CTRY_INF and yyyyMAPS folders) to indicate the presence of an INTERMAGNET Physical Media folder structure.

The .com and .exe files on earlier CD-ROMs are programs that were designed to run on Microsoft DOS operating system. They will not work on more recent versions of Microsoft Windows.

The IMAGxx.EXE files on earlier CD-ROMs contained software to view the data on the CD-ROM. This software only ran on Microsoft DOS operating system. This has been superseded by a multi-operating-system program for viewing the data (imcdview, the INTERMAGNET CD viewer).

The .PCX files, that preceded the current .GIF and .PNG files, are graphics files. PCX stands for PiCture eXchange, a format created by the ZSoft corporation. PCX is no longer in widespread use. Convertors from PCX to more modern formats are available online.

The CTRYLIST.IDX file (no longer used on the DVD/USB) is a text list of countries and their 3 letter codes.

The yyOBSDAT.DBF file (no longer used on the DVD/USB) is a database listing the contents of the CD-ROM. This was used by the DOS-based IMAGxx software (but is not used by the more recent imcdview software). The database is in Dbase format.

INTERMAGNET Format for Yearmean File : IYF V1.02

Magnetic data with 1nT or 0.1min of arc resolution are organized on a year file basis. One file contains all annual mean values of the geomagnetic field components that are available from the observatory.

File name: “YEARMEAN” and the three-letter observatory ID code as an extension. eg: YEARMEAN.BOU for Boulder.

Each file may have from 1 to 3 tables containing annual mean values. The file must contain a table of annual means for ALLDAYS, but may also contain tables of annual means for QUIET-DAYS and DISTURBED-DAYS.

Description of the Header Block

The header contains information on observatory name, ID-code, Colatitude, Longitude and Elevation to WGS-84 datum. It further contains the headers for each data columns.

eg: The header for Wingst is:

                         ANNUAL MEAN VALUES

                        WINGST, WNG, GERMANY.

COLATITUDE:  36.26       LONGITUDE:   9.07 E       ELEVATION:   50 m

 YEAR      D        I         H      X      Y      Z      F  * ELE Note
        Deg. min Deg. min     nT     nT     nT     nT     nT

Description of data space (75 characters per line including CrLf)

All data fields are right-justified. The field width must be maintained, either by zero-filling or space-filling. The ‘+’sign for positive values is optional.

_YYYY.yyy_DDD_dd.d_III_ii.i_HHHHHH_XXXXXX_YYYYYY_ZZZZZZ_FFFFFF_A_EEEE_NNNCrLf
....
....

YYYY.yyy

Epoch is given with 3 decimals

DDD_dd.d

Declination is given in degrees and decimal minutes of arc

III_ii.i

Inclination is given in degrees and decimal minutes of arc

HHHHHH

H-component is given in nT

XXXXXX

X-component is given in nT

YYYYYY

Y-component is given in nT

ZZZZZZ

Z-component is given in nT

FFFFFF

F-component is given in nT

A

Type of annual means. May be “A”ll, “Q”uiet, “D”isturbed, “I”ncomplete” or “J”ump. The “J” is not an annual mean value, but indicates a jump in the observatory recordings, which should be described in a note.

EEEE

recorded elements. eg:”XYZF” or “HDZF”

NNN

Note number

CrLf

Indicates a Carriage return Line feed

_

Represents a space

  • Missing angular values must be coded as three 9 digits, a space, two 9 digits, a dot and one 9 digit: 999 99.9

  • Missing component values must be coded as six 9 digits: 999999

  • Angular values are written as degrees and minutes. Values may be written in the range 0 to 360 or -180 to 180. Observatories may choose which range to use. Negative values must always have the minus sign before the degree field, never before the minute field (including values between 0 and -1 degrees, for example “-0 59” means a value of minus zero degrees fifty nine minutes). This applies to all types of records, including jump records.

Sample of a Yearmean File

                            ANNUAL MEAN VALUES

                        NARSARSUAQ, NAQ, GREENLAND

  COLATITUDE:  28.84       LONGITUDE: 314.56 E       ELEVATION:  4 meters

    YEAR      D        I        H      X      Y      Z      F  * ELE Note
           Deg.  '  Deg.  '     nT     nT     nT     nT     nT

 1983.500 326 41.6  77 15.8  12152  10156  -6673  53764  55120 A  DHZ
 1984.500 326 55.7  77 14.3  12171  10199  -6642  53736  55097 A  DHZ
 1985.500 327 11.1  77 12.9  12187  10242  -6604  53706  55071 A  DHZ
 1986.500 327 26.8  77 11.7  12201  10284  -6565  53679  55048 A  DHZ
 1987.500 327 44.5  77 09.9  12223  10336  -6524  53647  55022 A  DHZ
 1988.500 328 00.5  77 09.0  12235  10377  -6482  53633  55011 A  DHZ
 1989.000   0 02.6   0 00.7     -4      2     10     30     28 J  DHZ   1
 1989.500 328 13.8  77 07.2  12254  10418  -6452  53592  54975 A  DHZ
 1990.500 328 29.9  77 05.9  12271  10463  -6412  53571  54959 A  DHZ
 1991.500 328 45.6  77 04.9  12284  10503  -6371  53555  54946 A  DHZ
 1992.500 329 01.3  77 03.4  12302  10547  -6332  53525  54920 A  DHZ
 1993.500 329 17.9  77 01.6  12323  10596  -6292  53495  54896 A  DHZ
 1994.000   0 00.0   0 00.0     -1     -1      0     -2     -3 J  DHZ   2
 1994.500 329 34.3  77 00.7  12335  10636  -6247  53476  54880 A  DHZ
 1995.500 329 53.6  76 58.3  12366  10698  -6203  53444  54856 A  DHZ
 1996.500 330 13.6  76 56.0  12395  10759  -6155  53409  54828 A  DHZ
 1997.500 330 33.9  76 54.0  12423  10819  -6105  53381  54807 A  DHZ
 1998.500 330 55.6  76 52.2  12446  10878  -6048  53361  54793 A  DHZ
 1999.500 331 17.3  76 50.2  12473  10939  -5992  53332  54771 A  DHZ
 2000.500 331 39.0  76 48.4  12497  10998  -5934  53311  54756 A  DHZ
 2001.500 332 01.3  76 46.1  12527  11063  -5877  53278  54731 A  DHZ
 2002.500 332 23.6  76 44.2  12553  11124  -5817  53254  54714 A  DHZ
 2003.500 332 45.2  76 43.3  12564  11170  -5752  53237  54699 A  DHZ
 2004.500 333 07.8  76 40.5  12600  11240  -5695  53202  54674 A  DHZ
 2005.500 333 29.3  76 38.7  12624  11296  -5635  53176  54654 A  DHZ
 2006.500 333 50.4  76 36.2  12656  11360  -5580  53140  54626 A  DHZ
 2007.500 334 10.9  76 34.0  12686  11420  -5525  53113  54607 A  DHZ


 1983.500 326 42.3  77 15.1  12164  10167  -6677  53765  55124 Q  DHZ
 1984.500 326 56.3  77 13.3  12186  10213  -6648  53734  55098 Q  DHZ
 1985.500 327 11.6  77 12.0  12202  10256  -6611  53704  55073 Q  DHZ
 1986.500 327 27.4  77 10.8  12215  10297  -6571  53676  55048 Q  DHZ
 1987.500 327 44.9  77 09.4  12232  10345  -6527  53648  55025 Q  DHZ
 1988.500 328 00.8  77 08.2  12246  10387  -6487  53631  55011 Q  DHZ
 1989.000   0 02.6   0 00.7     -4      2     10     30     28 J  DHZ   1
 1989.500 328 14.4  77 06.6  12263  10427  -6455  53591  54976 Q  DHZ
 1990.500 328 30.0  77 05.3  12279  10470  -6416  53567  54956 Q  DHZ
 1991.500 328 46.1  77 04.0  12297  10515  -6376  53551  54945 Q  DHZ
 1992.500 329 01.6  77 02.7  12312  10556  -6336  53521  54919 Q  DHZ
 1993.500 329 18.2  77 00.9  12335  10607  -6297  53491  54895 Q  DHZ
 1994.000   0 00.0   0 00.0     -1     -1      0     -2     -3 J  DHZ   2
 1994.500 329 35.4  76 59.2  12357  10657  -6255  53470  54879 Q  DHZ
 1995.500 329 54.2  76 57.5  12380  10711  -6208  53443  54858 Q  DHZ
 1996.500 330 13.6  76 55.5  12403  10766  -6159  53407  54828 Q  DHZ
 1997.500 330 34.2  76 53.4  12431  10827  -6108  53380  54808 Q  DHZ
 1998.500 330 55.5  76 51.6  12456  10886  -6053  53359  54793 Q  DHZ
 1999.500 331 17.9  76 49.6  12483  10949  -5995  53330  54771 Q  DHZ
 2000.500 331 39.3  76 47.8  12507  11007  -5938  53308  54755 Q  DHZ
 2001.500 332 01.5  76 45.6  12535  11070  -5880  53278  54733 Q  DHZ
 2002.500 332 23.7  76 43.6  12562  11132  -5821  53252  54714 Q  DHZ
 2003.500 332 45.9  76 42.0  12584  11189  -5759  53234  54701 Q  DHZ
 2004.500 333 08.1  76 39.7  12613  11252  -5700  53200  54675 Q  DHZ
 2005.500 333 29.6  76 37.8  12640  11311  -5641  53177  54659 Q  DHZ
 2006.500 333 50.5  76 35.5  12669  11371  -5585  53141  54630 Q  DHZ
 2007.500 334 11.0  76 33.5  12694  11427  -5528  53114  54610 Q  DHZ


 1983.500 326 40.4  77 17.7  12121  10128  -6659  53763  55112 D  DHZ
 1984.500 326 54.6  77 16.5  12136  10168  -6626  53744  55097 D  DHZ
 1985.500 327 10.1  77 14.7  12158  10216  -6592  53707  55066 D  DHZ
 1986.500 327 25.6  77 13.7  12169  10255  -6552  53683  55045 D  DHZ
 1987.500 327 43.9  77 11.0  12205  10320  -6516  53645  55016 D  DHZ
 1988.500 327 59.5  77 10.9  12204  10349  -6469  53636  55007 D  DHZ
 1989.000   0 02.6   0 00.7     -4      2     10     30     28 J  DHZ   1
 1989.500 328 12.2  77 08.9  12228  10393  -6443  53598  54975 D  DHZ
 1990.500 328 30.0  77 07.3  12249  10444  -6400  53577  54959 D  DHZ
 1991.500 328 45.1  77 06.5  12258  10480  -6359  53560  54945 D  DHZ
 1992.500 329 00.8  77 05.6  12268  10517  -6316  53539  54927 D  DHZ
 1993.500 329 16.8  77 03.5  12295  10570  -6281  53502  54897 D  DHZ
 1994.000   0 00.0  00 00.0     -1     -1      0     -2     -3 J  DHZ   2
 1994.500 329 33.2  77 02.9  12300  10604  -6233  53481  54877 D  DHZ
 1995.500 329 52.6  76 59.7  12344  10677  -6195  53445  54852 D  DHZ
 1996.500 330 12.9  76 57.1  12378  10743  -6149  53411  54827 D  DHZ
 1997.500 330 33.7  76 54.8  12409  10807  -6099  53382  54805 D  DHZ
 1998.500 330 54.7  76 54.2  12416  10850  -6036  53371  54796 D  DHZ
 1999.500 331 17.0  76 51.9  12446  10915  -5980  53336  54769 D  DHZ
 2000.500 331 37.8  76 50.1  12472  10974  -5926  53317  54756 D  DHZ
 2001.500 332 00.3  76 47.0  12512  11048  -5873  53276  54726 D  DHZ
 2002.500 332 23.3  76 45.3  12536  11108  -5810  53256  54711 D  DHZ
 2003.500 332 44.1  76 45.7  12526  11134  -5738  53245  54698 D  DHZ
 2004.500 333 06.5  76 42.6  12567  11208  -5684  53206  54670 D  DHZ
 2005.500 333 29.1  76 40.1  12600  11275  -5625  53174  54647 D  DHZ
 2006.500 333 50.1  76 37.7  12631  11337  -5570  53140  54621 D  DHZ
 2007.500 334 10.9  76 34.9  12672  11407  -5519  53113  54604 D  DHZ

* A = All Days
* Q = Quiet Days
* D = Disturbed Days
* J = Jumps       jump value = old site value - new site value

ELE = Recorded elements from which the annual mean values were derived

Notes:   1. The jump in the values from 1988 to 1989 is due to
            establishment of a new absolute pillar during 1988.
         2. The jump in the values from 1993 to 1994 is due to
            a change in the difference delta-F between the PPM
            pillar and the absolute pillar. The change happened
            between spring 1989 and autumn 1993. Why and when
            is unknown.

Sample of Missing Values

   YEAR      D        I        H      X      Y      Z      F  * ELE Note
          Deg.  '  Deg.  '     nT     nT     nT     nT     nT

1983.500 999 99.9 999 99.9 999999 999999 999999 999999 999999 A  DHZ
1984.500 999 99.9  77 14.3  12171 999999  -6642  53736  55097 A  DHZ

INTERMAGNET CD-ROM Software

The INTERMAGNET CD-ROM software is a menu-driven program that allows the user to display data in both graphics and text modes. It also allows the user to Save the graphics in the form of *.PCX files that can then be imported into other programs that accept the PCX format; and also Save the text in the form of ASCII files to the hard drive or floppy disk. Output may also be sent to an Epson-compatible dot-matrix, or Hewlett-Packard Laserjet-compatible printer for both plots and text.

Starting the software brings up a “Welcome” screen, and an ENTER command brings the user into the HOME screen, with menu options for YEAR, COUNTRY, OBSERVATORY, DATE-RANGE, AND MODEOUTPUT. The “8” and “9” keys allow the user to scroll through the choices, which are highlighted as the user moves through them. Pressing the “ENTER” key selects the highlighted option, and activates pop-up menus with further options. All options may be selected using the 8, 9, and ENTER keys. Selections may also be made with the use of “Hot Keys”, which are the first letter of each option, and indicated in the software by use of a different color in the menu choices. Pressing the particular Hot Key activates that menu choice immediately. Hot Keys are indicated in this manual by the use of bold type, for example, S(ave) means that if the “S” key is pressed for the Save option, it is executed immediately. Once all selections have been made, the EXECUTE option retrieves and displays the chosen options. Pressing the “ALT” and “E” keys simultaneously will exit the user back to DOS at any time, and from anywhere within the program.

There are 6 MODE-OUTPUT options:

  1. minute value plots,

  2. minute values as text,

  3. mean hourly value plots,

  4. mean hourly values as text,

  5. K-Index values as text,

  6. a conversion option that converts data from the 32-bit binary format into the World Data Center (WDC) ASCII format.

The WDC format option was included to allow users with existing software designed for this format to output the desired data and import it into their existing programs.

Help screens are available throughout the program with the use of the “F1” key. When the user is in a particular highlighted menu item, the F1 key provides a help screen about that item. In addition, information screens are available about a particular country using the “F4” key, and about the particular observatory using the “F3” key. These option keys appear on a menu bar on the screen when the COUNTRY and/or OBSERVATORY option is highlighted. The user can scroll through these README screens using the “8” and “9” keys, once the F3 or F4 key has been pressed.

Within the program, menu bars located at the top and bottom of the screen, offer a variety of options. A map screen of each country is available, showing the observatories contributing to the CD-ROM from that country, by using the V(iew map) key once the particular country has been chosen. Also, an A(bout) screen is available for each country showing the organization’s address and the names of persons to contact regarding their geomagnetism program. Users can change observatories (within a given country) and date ranges while in the output mode without having to return to the HOME screen. Individual components in the plot outputs may be selected and displayed at an enlarged scale using the C(omponent) option (Hot Key “C”) from the menu bar. While in the Component mode, the T(oggle) key toggles on and off a histogram of hourly means and K-Index values (when available) for the minute plots, and the Ak values for the mean hourly values plots. P(rint) and S(ave) options are also available for both graphics and text modes. Starting with the 1992 CD-ROM, a Base(l)ine option was made available that provides absolutes and baseline calibration data for each station. These data can be viewed either in the form of a plot for each component, or in text mode showing the observed and adopted values for the year. The plots also show a delta-F plot of the differences between the observed and computed total field (F) for some stations; and the text mode contains a comments section pertaining to baseline jumps and other observatory adjustments.

Other options that are available from the menu bars include a B(eginning day) choice that resets the output to the beginning of the selected date-range, a F2(Flow) chart of the software program that indicates where the user is within the program and what outputs are available, and a R(escale) option that allows the user to set the scale of the plots. This feature disables the autoscaling of the plots, and enables a user to plot data at a fixed scale for comparison of different days and/or observatories on the same full-range scale. However, if the data cannot fit within the plot range, the Rescale option will override the user-selected scale and autoscale to fit the data. While in the HOME screen, the P(references) option allows the user to customize certain parameters including the text and background colors, the type of printer being used, and the CD-ROM and output drive letter designations, it is also possible to add CRLF (carriage return / linefeed characters) to the records in any data converted to WDC-files.