Volume VGPW_2004
Voyager 2
Plasma Wave Spectrometer Waveform

PWS Data Archive
Entire Mission
Planetary Plasma Interactions Discipline Node
of the
Planetary Data System

Introduction

This volume set contains the Voyager 2 Plasma Wave Spectrometer Waveform data from the entire mission, submitted to the Planetary Data System (PDS). Every effort has been made to assure that the data and documentation are of the best possible quality. However, mistakes are inevitable. The PPI Node of the PDS will maintain an online list of ERRATA where errors and updates are documented. Should any user of this product find an error on this volume, please report the error to the PPI Node so that the finding can be made public. All users are encouraged to verify the "correctness" of the data prior to submitting any publications or other work based on these data. Users of these data are encouraged to acknowledge both the PDS and the principal investigators of the instruments whose data is used in analysis in all publications.

IMPORTANT INFORMATION ABOUT THIS DISK -- READ THIS FIRST!

This volume set contains Voyager 2 PWS Waveform data from the entire mission. New data will be added on subsequent volumes as they become available. This volume, VGPW_2004, includes all available waveform files with start times (SCET) in the interval 1979-07-08 21:46:23.025 through 1981-08-23 00:58:23.681. Edited telemetry data in the form of 4-bit waveform samples are provided at full resolution.

KEY THINGS TO KNOW IN USING DATA ON THIS DISK:

All data files are stored in the "DATA" branch of the directory tree by spacecraft clock. The "DATA" directory branches off into "DATA/BROWSE", containing browse frequency-time spectrogram images, and "DATA/WFRM", containing raw waveform files. Beneath each of these are one or more directories named "Pn" indicating the spacecraft clock partition number, and beneath those are subdirectories named "V204nn", where nn can range from 01 to 35. Each of the "V204nn" subdirectories may contain up to 20 data files named "Cmmmmmnn.DAT" (or "Cmmmmmnn.PNG"), where "mmmmmnn" is determined by the corresponding spacecraft clock value. The data are stored in binary with format descriptions included as separate files. Time values are expressed in spacecraft clock except for the header in which the spacecraft event time (SCET) is given for the time corresponding to line 001 of each MOD60 count, that is, the time of the first data in the frame if all the data were present. Note that for various reasons, some header information on the correct SCET, partition number, and spacecraft ID are either unreliable or missing. Therefore, the user should only use the spacecraft ID and SCET given in the ASCII string beginning at byte number 249 in the header. This is the only location for which spacecraft ID and spacecraft event time are known to be accurate and reliable in all cases.

The documentation for this volume is located in the CATALOG directory. The data set is documented as part of the archive (DATASET.CAT); so is the PWS instrument (PWSINST.CAT), the Voyager mission (MISSION.CAT) and spacecraft (INSTHOST.CAT), the PWS team (PERSON.CAT), and useful literature references (REF.CAT).

All data files on this CD-ROM are described by detached PDS labels (.LBL) and format files (.FMT). Metadata are stored as text files with the data. Information on the particular form of metadata used in the PDS catalog can be found in the CATALOG directory.

Relationship to Other Data Sets

The data on this disk are Voyager Plasma Wave Spectrometer Waveform Data which are the highest resolution wave information available from the Voyager Plasma Wave Receiver. Since they require very high data rates these data are only available for short periods of time with a low duty cycle. Low resolution spectrum analyzer data which are available for all times during which the Plasma Wave Receiver is on and telemetry is available are found in data sets with dataset_id's like:

which are available elsewhere within the Planetary Data System.

Volume Set Information

This CD-ROM is the fourth volume of the VGPW_20xx set. This volume, VGPW_2004, contains all available PWS waveform data from the spacecraft event time (SCET) interval 1979-07-08 21:46:23.025 through 1981-08-23 00:58:23.681. The initial release will include at least 7 CD-ROMs with additional volumes being added as new data are archived.

Volume Format Information

The disk is organized into a hierarchical directory structure. The disk is formatted according to both ISO 9660 and POSIX (UNIX) standards in order to accommodate users on a wide variety of platforms. This volume does not contain any Extended Attribute Records (XAR). Thus, VAX/VMS users may have some problems accessing files on this volume.

File Formats

The data files on this volume are ASCII text and binary files. Browse data are provided in Portable Network Graphics (.PNG) format. All data files are described by detached PDS labels. A detached label file has the same name as the data file that it describes, but with the extension .LBL. For example, the file C2345644.DAT is accompanied by the detached label file C2345644.LBL in the same directory. File names within this archive comply with the "8.3" convention for compliance with ISO 9660 Level 1 interchange requirements.

All documents, detached PDS labels, and HTML files are stream format files, with a carriage return (ASCII 13) and a line feed character (ASCII 10) at the end of the record. This allows the files to be read by MacOS, DOS, Windows, UNIX, and VMS operating systems. UNIX system users will see an unnecessary carriage return character (^M) at the end of each line. Mac users will see an unnecessary line feed character (^J) at the start of each line.

ASCII tabular data files (.TAB) are formatted so that they may be read directly into many database management systems (DBMS) or spreadsheet programs on various computers. All fields are of fixed length and are separated by white space or commas. Character fields are left justified, and numeric fields are right justified. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a normal text file on other computers.

The document, PDS label, and ASCII table files on this volume can be viewed with a Web browser. Note that to view these files, the browser may need to be configured to recognize files with extensions of .CAT, .LBL, and .TAB as text files. Users with Web browsers also can navigate the disk via the HTML file AAREADME.HTM in the disk's root directory and the HTML files in the EXTRAS directory.

PDS labels are object-oriented. The object to which the label refers (e.g., SERIES, TABLE, etc.) is denoted by a statement of the form: 

^object = location
in which the caret character (^, also called a pointer in this context) indicates that the object starts at the given location. For an object in the same file as the label, the location is an integer representing the starting record number or byte of the object (the first record/byte in the file is 1). For an object located outside the label file, the location denotes the name of the file containing the object, along with the starting record or byte number. For example: 
^SERIES            = ("20903684.DAT", 3)
indicates that the SERIES object begins at record 3 of the file 20903684.DAT, in the same directory as the detached label file. Below is a list of the possible formats that use the ^object keyword. 
^object = n
^object = n<BYTES>
^object = ("filename.ext",n)
^object = ("filename.ext",n<BYTES>)
where
n is the starting record or byte number of the object, counting from the beginning of the file (record 1, byte 1); default is record number.
<BYTES> indicates that number given is in units of bytes.
filename upper-case file name.
ext upper-case file extension.

In cases where many files of the same format or structure are present, the structure description component is detached from the primary label. This minimizes repeating information which does not vary from file to file. In these cases, a format file (.FMT) contains the file structure information and the base label (.LBL) describes the parameters which generally do vary from file to file (number of records, file name, start/stop time, etc.). When a format file is used within the PDS label, the syntax is: 

^STRUCTURE    = filename
Example: 
^STRUCTURE    = "EDRHDR.FMT"

Syntactically, the contents of the format file can be inserted directly into the base label such that the entire file contents replace the single line ^STRUCTURE = filename.

Errata

There is a file called ERRATA.TXT found at the root level of this volume which contains a list of known deficiencies or caveats associated with data on this volume at the time this CD was published. Any changes or errors that are found on this or any VGPW_20xx CD-ROM after the production of this volume can be found on the PPI Node errata Web page ( http://www.igpp.ucla.edu/ssc/pdsppi/Welcome.html). Also, they can be obtained via anonymous FTP at ftp.igpp.ucla.edu. The account name is "anonymous" and the password should be your e-mail address (it's polite to leave an audit trail). Locate yourself in the PDS errata directory (cd pds/ERRATA/VGPW_20xx), and transfer the file ERRATA.TXT ( get ERRATA.TXT).

If you find an error on this disk, please report the error to the PDS Operator at the PPI Node of the PDS.

Internet pds_operator@igpp.ucla.edu
Telephone (310) 206-6073
U.S. Mail PDS Operator
c/o Dr. Raymond Walker
UCLA - IGPP
Los Angeles, CA 90095-1567

Only through support and feedback of the users of these data can an effective errata list be maintained.

Software

There is no software provided with these data at this time.

Volume Contents and Structure

This section describes the volume structure and naming conventions. Below is a tree diagram of the CD-ROM, followed by a description of the directory function and key files in each directory.

[VGPW_2004]Root directory
|
|- AAREADME.TXT Describes volume contents, organization and CD-ROM use
|- AAREADME.LBL Label file for AAREADME.HTM
|- AAREADME.HTM HTML version of AAREADME.TXT. Can be viewed in a Web browser and used to navigate the data. (this file).
|- ERRATA.TXT Describes known deficiencies or caveats in the data or on this CD-ROM.
|- VOLDESC.CAT High-level description of CD-ROM contents.
|- [CATALOG] Information on data sets and how they are processed and produced. Also contains information regarding Voyager 2, the instrument covered by this volume, personnel involved, and references from various documents including those contained in the CATALOG directory.
|
|- [DATA] Contains all data in a branching tree structure of subdirectories.
|- [DOCUMENT] Contains documents describing the data on the volume.
|- [EXTRAS] Contains files which facilitate use of the disk, but which are not required for such use. These files include HTML pages with links to data on the disk.
|- [INDEX] Contains an index of PDS label files for all data archived on the CD-ROM and the volume set to date.

Driver and Hardware Information

This disk has been formatted according to the ISO standard for CD-ROM production (9660) with level 1 compliance. Any system which complies with this standard (all of them should) should be able to access this disk.

Contacts

The person most directly responsible for the construction and release of this CD-ROM is Mr. Steven Joy. He was the PPI Node Data Administrator at the time this disk was created and understands as much about the disk structure and data organization as anyone. Other PPI personnel who may be aware of issues related to this CD-ROM include Dr. William Kurth and Dr. Raymond Walker, the PDS/PPI Node manager.

For questions or problems regarding this CD-ROM, please contact the PDS/PPI PDS operator:

Internet pds_operator@igpp.ucla.edu
Telephone (310) 206-6073
U.S. Mail PDS Operator
c/o Dr. Raymond Walker
3845 Slichter Hall
UCLA - IGPP
Los Angeles, CA 90095-1567

For questions regarding PDS Standards or other CD-ROM's available from the PDS, please contact PDS Operator at the PDS Central Node (at JPL):

Internet pds_operator@jpl.nasa.gov
Telephone (818) 354-4321
U.S. Mail Planetary Data System, PDS Operator
Jet Propulsion Laboratory
Mail Stop 202-101
4800 Oak Grove Dr.
Pasadena, CA 91109-8099

The PDS and the Planetary Plasma Interactions (PPI) Node in particular, assume no legal liability for errors on this disk. All users are encouraged to verify the "correctness" of the data prior to submitting any publications or other work based on these data. Errors on this disk should be reported back to the PPI Node of the PDS through the ERRATA reporting procedures described above.

Extra Features

Included in the EXTRAS directory of this volume is a Graphical Data Browser Index which lists time intervals included on individual "contact sheets" containing miniature versions of frequency-time spectrograms of all the data contained in this volume. These contact sheets are useful for browsing long time periods to search for large-scale features or to determine if data are available during a specific time of interest. Using a sufficiently enabled web browser, the user can click on one of the small spectrograms to obtain a full-resolution spectrogram with options to view the associated label file, save the binary waveform file, or link to the Voyager PWS web site to do more detailed online analysis.