Create a PDS3 label that describes a data table.
Our data is a table contains a time series of data. It has four fields: time stamp and and 3D vector. We want to create an PDS3 label that describes the data table.
Our data table looks like:
2012-01-01T00:00:30 0.488 -0.866 -2.537 2012-01-01T00:01:30 0.521 -0.833 -2.616 2012-01-01T00:02:30 0.412 -1.025 -2.658 2012-01-01T00:03:30 0.534 -0.978 -2.743 2012-01-01T00:04:30 0.591 -0.939 -2.755 2012-01-01T00:05:30 0.546 -0.876 -2.680 2012-01-01T00:06:30 0.643 -0.761 -2.702 2012-01-01T00:07:30 0.969 -0.194 -2.483 2012-01-01T00:08:30 1.007 0.131 -2.307 2012-01-01T00:09:30 0.640 -0.626 -2.267 2012-01-01T00:10:30 0.453 -1.074 -2.477 2012-01-01T00:11:30 0.479 -0.966 -2.355 2012-01-01T00:12:30 0.595 -0.789 -2.423
We will store this in a file called timeseries.tab.
Since this a fixed width, plain text file without header information we need additional information in order to describe the layout and content of the table. For each field we will need know the name, units, data type, start byte, width, and a short description. We will also need to have a description of the data. A CSV file is a convienent way to store this information. For the example table this would be:
# Cassini magnetic-field 1 minute averages for the year 2012 in RTN # coordinates. RTN coordinates consist of R (radial component, Sun to # the spacecraft), T (tangential component, parallel to the Solar # Equatorial plane and perpendicular to R), and N (normal component, # completes right handed set). # # These MAG data were processed (calibrated, rotated into RTN # coordinates, and averaged) by the Cassini MAG team at Imperial # College. They were provided to PDS by the MAG team Co-I at UCLA. # Trajectory and the number of points in the average were added at the # PDS/PPI node. For more information on this and previous versions, # please refer to the PDS catalog file for this data set # (CO_MAG_CAL_1MIN_DS.CAT). Name Number Unit Data_Type Start_Byte Bytes Description TIME 1 N/A TIME 1 19 Spacecraft event time of the sample. BR 2 nT ASCII_REAL 21 10 The radial component (R) points from the Sun to the spacecraft,positive away from the Sun. BT 3 nT ASCII_REAL 32 10 RTN tangetial (T) component of the magnetic field in nT. T is parallel to the Solar Equatorial plane (Omega[Sun] x R). BPHI 4 nt ASCII_REAL 42 10 RTN normal (N) component of the magnetic field in nT. N completes the right handed set, and is roughly normal to the Solar Equatorial plane.
We will store this in a file called fields.csv.
Our velocity template will be a PDS3 label with some information already filled in. Information specific to the table (columns, record count, file size, etc.) will be generate using igpp.docgen. Our template looks like:
PDS_VERSION_ID = PDS3
DATA_SET_ID = "CO-E/SW/J/S-MAG-4-SUMM-1MINAVG-V1.0"
STANDARD_DATA_PRODUCT_ID = "FGM L1B RTN 1MIN"
PRODUCT_ID = "$File.getBaseName($options.data_file)"
PRODUCT_TYPE = "DATA"
PRODUCT_VERSION_ID = "1"
PRODUCT_CREATION_TIME = 2013-03-03T19:56:41
START_TIME = 2012-01-01T00:00:30
STOP_TIME = 2012-01-01T00:22:30
INSTRUMENT_HOST_NAME = "CASSINI ORBITER"
INSTRUMENT_HOST_ID = "CO"
MISSION_PHASE_NAME = "EXTENDED-EXTENDED MISSION"
TARGET_NAME = "SATURN"
INSTRUMENT_NAME = "DUAL TECHNIQUE MAGNETOMETER"
INSTRUMENT_ID = "MAG"
DESCRIPTION = "$layout.description"
SPICE_FILE_NAME = "CAS_2012.MK"
^TABLE = "$options.data_file"
MD5_CHECKSUM = "$File.getMD5($options.data_file)"
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = $options.record_bytes
FILE_RECORDS = $Calc.floor($Calc.perform($File.getSize($options.data_file), "/", $options.record_bytes))
OBJECT = TABLE
INTERCHANGE_FORMAT = "ASCII"
ROWS = $Calc.floor($Calc.perform($File.getSize($options.data_file), "/", $options.record_bytes))
COLUMNS = $layout.fields.size()
ROW_BYTES = $options.record_bytes
DESCRIPTION = ""
#foreach ($field in $layout.record)
OBJECT = COLUMN
NAME = "$field.Name"
COLUMN_NUMBER = $field.Number
UNIT = "$field.Unit"
DATA_TYPE = $field.Data_Type
START_BYTE = $field.Start_Byte
BYTES = $field.Bytes
DESCRIPTION = "$field.Description"
END_OBJECT = COLUMN
#end
END_OBJECT = TABLE
END
We will store this in a file called example-pds3.vm.
In the template we expect information about the table (description and fields) to be in a context called "layout" and the name of the data file to be passed on the command-line (which appears in the "options" context). This template uses methods to determine some information. For example, the MD5 checksum is calcualted by calling the getMD5() method of the File context, passing the file name provided on the command line. See: $File.getMD5($options.data_file). It also uses the floor() and perform() methods of the Calc context to determine the number of records (rows) in the file. Finally, it uses the getBaseName() method of the File context to extract the base name of the data file and assigned it to the PRODUCT_ID which is a convention when creating PDS3 labels.
Running igpp.docgen with the command:
Instructs igpp.docgen to parse the file "fields.csv" and place the results in a context named "layout". Since the extension on "fields.csv" is ".csv" igpp.docgen will parse the file as a set of tab separated values, creating a record for each non-commented line in the file. We also specify that the output should be well formatted PDS3 metadata (-f pds3).
Running this command will generate an XML document that looks like:
PDS_VERSION_ID = PDS3
DATA_SET_ID = "CO-E/SW/J/S-MAG-4-SUMM-1MINAVG-V1.0"
STANDARD_DATA_PRODUCT_ID = "FGM L1B RTN 1MIN"
PRODUCT_ID = "timeseries"
PRODUCT_TYPE = "DATA"
PRODUCT_VERSION_ID = "1"
PRODUCT_CREATION_TIME = 2013-03-03T19:56:41
START_TIME = 2012-01-01T00:00:30
STOP_TIME = 2012-01-01T00:22:30
INSTRUMENT_HOST_NAME = "CASSINI ORBITER"
INSTRUMENT_HOST_ID = "CO"
MISSION_PHASE_NAME = "EXTENDED-EXTENDED MISSION"
TARGET_NAME = "SATURN"
INSTRUMENT_NAME = "DUAL TECHNIQUE MAGNETOMETER"
INSTRUMENT_ID = "MAG"
DESCRIPTION = " Cassini magnetic-field 1 minute averages for th
e year 2012 in RTN coordinates. RTN coordinates consist of R (radial component,
Sun to the spacecraft), T (tangential component, parallel to the Solar Equatoria
l plane and perpendicular to R), and N (normal component, completes right handed
set). These MAG data were processed (calibrated, rotated into RTN coordinates,
and averaged) by the Cassini MAG team at Imperial College. They were provided to
PDS by the MAG team Co-I at UCLA. Trajectory and the number of points in the av
erage were added at the PDS/PPI node. For more information on this and previous
versions, please refer to the PDS catalog file for this data set (CO_MAG_CAL_1MI
N_DS.CAT)."
SPICE_FILE_NAME = "CAS_2012.MK"
^TABLE = "timeseries.tab"
MD5_CHECKSUM = "708bf8cfd80f2a544543661bcaf2bb61"
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 54
FILE_RECORDS = 23
OBJECT = TABLE
INTERCHANGE_FORMAT = "ASCII"
ROWS = 23
COLUMNS = 7
ROW_BYTES = 54
DESCRIPTION = ""
OBJECT = COLUMN
NAME = "TIME"
COLUMN_NUMBER = 1
UNIT = "N/A"
DATA_TYPE = TIME
START_BYTE = 1
BYTES = 19
DESCRIPTION = "Spacecraft event time of the sample."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "BR"
COLUMN_NUMBER = 2
UNIT = "nT"
DATA_TYPE = ASCII_REAL
START_BYTE = 21
BYTES = 10
DESCRIPTION = "The radial component (R) points from the Sun to
the spacecraft,positive away from the Sun."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "BT"
COLUMN_NUMBER = 3
UNIT = "nT"
DATA_TYPE = ASCII_REAL
START_BYTE = 32
BYTES = 10
DESCRIPTION = "RTN tangetial (T) component of the magnetic fiel
d in nT. T is parallel to the Solar Equatorial plane (Omega[Sun] x R)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "BPHI"
COLUMN_NUMBER = 4
UNIT = "nt"
DATA_TYPE = ASCII_REAL
START_BYTE = 42
BYTES = 10
DESCRIPTION = "RTN normal (N) component of the magnetic field i
n nT. N completes the right handed set, and is roughly normal to the Solar Equat
orial plane."
END_OBJECT = COLUMN
END_OBJECT = TABLE
END