This volume 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.
This volume contains Voyager 2 PWS Waveform data from the entire mission. New data will be added as updates to this volume as they become available. This volume, VGPW_2001, includes all available waveform files with start times (SCET) in the interval 1979-04-28 through 2006-03-07. 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 files are stored in the "DATA" and "BROWSE" directory trees by spacecraft clock. The "DATA" directory contains raw waveform files and the "BROWSE" directory contains frequency-time spectrogram images. Beneath each of these are one or more directories named "Pn" indicating the spacecraft clock partition number, and beneath those are subdirectories named "V2Pn_mmm", where n is the spacecraft clock partition number and mmm is the subdirectory number, which starts over at 001 for each clock partition. Each of the "V2Pn_mmm" 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 volume 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.
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:
Two versions of this volume set exist, version 1 consisted of multiple smaller volumes per spacecraft. This version, version 2, contians all PWS waveform data from Voyager 2 released to the PDS on the single volume VGPW_2001. This release contains data from the spacecraft event time (SCET) interval 1979-04-28 through 2006-03-07. Subsequent releases of this volume will contain new data as they are archived.
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.
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 "27.3" convention for compliance with ISO 9660 Level 2 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:
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:^object = location
^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:
Example:^STRUCTURE = filename
^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.
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_2001 volume after the production of this volume can be found on the PPI Node errata Web page ( http://www.igpp.ucla.edu/cgi-bin/ditdos?errata=VGPW_2001).
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.
Example C and IDL code for reading the archived binary data as well as a complete display and analysis Java (TM) application are provided in the EXTRAS/SOFTWARE directory. This software is provided "as is" and is distributed as a service to the community.
More information is provided in the file EXTRAS/SOFTWARE/SOFTINFO.TXT.
This section describes the volume structure and naming conventions. Below is a tree diagram of the volume, followed by a description of the directory function and key files in each directory.
[VGPW_2001] Root directory
|
|- AAREADME.TXT Describes volume contents, organization,
| and 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 volume. (this file)
|
|- ERRATA.TXT Describes known deficiencies or caveats in
| the data or volume set.
|
|- VOLDESC.CAT High-level description of volume contents.
|
|- [BROWSE] Contains browse summary plots in PNG format.
|
|- [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.
|
|- [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 an HTML graphical
| data browser index, example software code
| for reading the data, and a full-featured
| analysis application.
|
|- [INDEX] Contains an index of PDS label files for
all data archived on this volume and on the
volume set to date.
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 launch an interactive Java application for analyzing the data in both time and frequency domains.
The person most directly responsible for the construction and release of this volume 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 volume include Dr. William Kurth and Dr. Raymond Walker, the PDS/PPI Node manager.
For questions or problems regarding this volume, 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 volumes 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.
All trademarks are acknowledged as the property of their respective owners. The producers and publishers of this archive do not endorse any commercial entities which may be mentioned for clarity.
These data were collected under the auspices of the Voyager Project. Donald A. Gurnett was the Plasma Wave Spectrometer Principal Investigator. The archiving effort at The University of Iowa was supported by L. Granroth and C. Piker. Java software was developed by J. Faden and E. West.
This archiving effort was supported by the Planetary Plasma Interactions Node of the Planetary Data System. Assistance was provided by S. Joy and J. Mafi of the University of California, Los Angeles, and by S. Adams of the Jet Propulsion Laboratory.