CASSINI PROJECT IMAGING SCIENCE SUBSYSTEM (ISS) ARCHIVE VOLUME SOFTWARE INTERFACE SPECIFICATION (SIS) JPL D-27548 Version 2.0 May 26, 2005 SIGNATURE PAGE Custodian: Leslie Pieri Haley, ISS Archive Lead Approved: ________________________________________________ Carolyn Porco, ISS Team Lead ________________________________________________ Diane Conner, Cassini Archive Data Engineer ________________________________________________ Susan LaVoie, PDS Imaging Node Manager TABLE OF CONTENTS 1. Introduction 1.1. Purpose and Scope 1.2. Content Overview 1.3. Applicable Documents and Constraints 1.4. Relationships with Other Documents 2. Archive Volume Contents 2.1. ROOT Directory Contents 2.2. DATA Directory Contents and Naming 2.3. INDEX Directory Contents 2.4. DOCUMENT Directory Contents 2.5. CATALOG Directory Contents 2.6. LABEL Directory Contents 2.7. CALIBRATION Directory Contents 2.8. EXTRAS Directory Contents 3. Archive Volume Format 3.1. File Formats 3.1.1. Document File Format 3.1.2. Tabular File Format 3.1.3. PDS Label Format 3.1.4. Software File Format 3.1.5. Catalog File Format 3.1.6. Science Data File Formats 4. Archive Volume Generation 4.1. Data Transfer Methods and Archive Volume Creation 4.2. Validation Methods 4.3. Data Product Sizes and Delivery Rates 4.4. Archive Media Characteristics 4.5. Backup and Duplicates 4.6. Labeling and Identification 5. Support Staff and Cognizant Persons 6. Appendices DOCUMENT CHANGE LOG Date Change -------- -------------------------------------------------------------------- 2-27-03 Various. Also updated version number (to 0.6). Affected portions: throughout Version 1 draft document. 11-1-03 Peer Design Review/Sample Volume comments incorporated modifications resulting from sample volume generation/review process. Updated Version number (to 1.0) and JPL Document number for signature distribution. Affected portions: throughout Version 1 draft document. 2-1-04 Signature SIS version post first sample volume review. Affected portions: throughout Version 1 document. 12-10-04 Archive Volume Peer Review release; Version updated to 2.0. Affected portions: Peer Review Volume Release; Incorporates second sample review comments; Initial calibration dataset release. 4-20-05 Implemented additional changes following Archive Peer Review. Major affected portions: directory contents, description of file formats, description of Calibration volume. Version updated to 2.1. 05-26-05 Updated Calibration volume numbering references and some minor edits concerning filenames. TBD ITEMS Section Description --------------------------------------- ------------------------------------ 2.2 Calibration Volume - Data Directory Complete calibration filename set (subject to change throughout the mission) 4.3 Data Product Sizes and Delivery Rates Expected number of calibration dataset volumes; Total expected dataset size (subject to change) ACRONYMS AND ABBREVIATIONS ASCII American Standard Code for Information Interchange CICLOPS Cassini Imaging Central Laboratory for Operations CISSCAL Cassini Imaging Science Subsystem Calibration Software CODMAC Committee On Data Management And Computation DVD Digital Video Disc EDR Experiment Data Record GIF Graphics Interchange Format HTML HyperText Markup Language IDL Interactive Data Language IMG Image IO Instrument Operations (Team) ISO International Standards Organization ISS Imaging Science Subsystem JPEG Joint Photographic Experts Group JPL Jet Propulsion Laboratory MIPS Multimission Image Processing Subsystem NAC Narrow Angle Camera NASA National Aeronautics and Space Administration NSSDC National Space Science Data Center PDF Adobe? Portable Document Format PDS Planetary Data System SIS Software Interface Specification SOI Saturn Orbit Insertion TBD To Be Determined TDS Telemetry Data System WAC Wide Angle Camera GLOSSARY Archive - An archive consists of one or more data sets, along with all the documentation and ancillary information needed to understand and use the data. An archive is a logical construct independent of the medium on which it is stored. Archive Volume, Archive Volume Set - A volume is a unit of media on which data products are stored; for example, one CD-R or DVD-R. An archive volume is a volume containing all or part of an archive; that is, data products plus documentation and ancillary files. When an archive spans multiple volumes, they are called an archive volume set. Usually the documentation and some ancillary files are repeated on each volume of the set, so that a single volume can be used alone. Catalog Information - Descriptive information about a data set (e.g. mission description, spacecraft description, instrument description), expressed in Object Description Language (ODL), which is suitable for loading into a PDS catalog. Data Product - A labeled grouping of data resulting from a scientific observation. A product label, which may be attached or detached, identifies, describes, and defines the structure of the data. An example of data is an image, a spectrum table, or a time series table. Together, a data file plus its accompanying label comprise a data product. Data Set - An accumulation of data products. A data set together with supporting documentation and ancillary files is an archive. 1. Introduction 1.1. Purpose and Scope This Software Interface Specification (SIS) is intended to be used by those who wish to understand the contents and formats for the Cassini Project Imaging Science Subsystem (ISS) archive collection. Typically, these individuals would be planetary scientists, software engineers or data analysts using the ISS archive. The specifications in this document apply to the ISS archive, which includes the ISS Experiment Data Record (EDR) data sets and ISS Calibration datasets, being generated on Digital Video Disk (DVD) volumes by the Cassini ISS team's Cassini Imaging Central Laboratory for Operations (ISS/CICLOPS). 1.2. Content Overview This SIS describes the format, content and generation details of the ISS archive. Section 1 provides an introduction to the archive; Section 2 (Archive Volume Contents) describes the structure of the archive volumes and briefly describes the contents of each file; Section 3 (Archive Volume Format) describes the file formats types provided on these archive volumes; Section 4 (Archive Volume Generation) describes the volume assembly and generation process and the procedures for transferring the archive to the PDS, and Section 5 (Support Staff and Cognizant Persons) lists the individuals associated with the Cassini ISS archive volume generation. 1.3. Applicable Documents and Constraints This Archive Volume SIS is intended to be consistent with the following documents: 1. Cassini Program Data Management Plan (PDMP), JPL D-12560, PD 699-061, Rev. B, April 1999. 2. Cassini / Huygens Program Archive Plan for Science Data, JPL D-159576, PD 699-068, Version 3, March 2004. 3. Cassini Imaging Science Subsystem (ISS) Tour VICAR Image Data File and Detached Planetary Data System (PDS) Label Software Interface Specification (SIS), Tour Version 1.0, JPL D-24724, DOIS-002, October 4, 2002, and the Cruise Version of this document (not numbered). 4. Planetary Data System Data Preparation Workbook, February 17, 1995, Version 3.1, JPL D-7669, Part 1. 5. Planetary Data System Standards Reference, August 1, 2003, Version 3.6, JPL D-7669, Part 2. 6. ISO 9660-1988, Information Processing - Volume and File Structure of CD-ROM for Information Exchange, April 15, 1988. 7. Universal Disk Format Specification, Revision 1.02, August 30, 1996, Optical Storage Technology Association (OSTA). 8. Planetary Data Dictionary Document, August 28, 2002, JPL D-7116, Rev E. Produced by the Cassini ISS team, the reference below provides a comprehensive description of the team's science objectives, details on the ISS camera instrument, a discussion on the instrument calibration, and other valuable dataset information. This publication serves as excellent complement to the ISS archive volumes and should be referred to prior to any extensive usage of the datasets. 9. Cassini Imaging Science: Instrument Characteristics and Capabilities and Anticipated Science Investigations at Saturn, Space Science Review, submitted 2004. 1.4. Relationships with Other Documents This SIS could be affected by any change in the design of the ISS standard data products produced by the Cassini Instrument Operations Team (Applicable Document #3). Additionally, this SIS could be impacted by higher-level requirement changes in any of the applicable documents (Numbered 1-8) above. 2. Archive Volume Contents The ISS archive is comprised of a 2-volume scheme. The first volume is referred to as the 'DATA' volume and is considered to be mostly static. These volumes contain the raw (uncalibrated) ISS experiment data record image files (EDRs), attached and detached label files, helpful and required Planetary Data System (PDS) files and useful documentation related to the image datasets. Static refers to the fact that, once produced and validated, the contents of these volumes are less likely to be updated or modified. Exceptions are those cases where new information is made available or where images are reprocessed, due to previous errors, and are made available on later volumes. No calibration files are found on the DATA volumes, except in-flight calibration images found as sequenced in spacecraft clock (SCLK) order. The second volume is referred to as the dynamic 'CALIBRATION' volume and contains all calibration-related files, except in-flight images as mentioned above. The contents of these volumes have the inherent property that they continue to evolve and improve as the knowledge of the mission parameters improves. As a result these volumes are updated periodically and released with the latest available calibration-related data and information. The ISS team is not performing systematic processing with the imaging EDRs. However, to support future users of the ISS EDR datasets in performing their own calibration processing, the CALIBRATION volumes include the ISS calibration processing software and other related files to support calibration processing. Included on the calibration volumes are the calibration data files, a set of sample calibrated images generated using the ISS team's calibration processing software, the image files produced during ground calibration, calibration algorithms and documentation, along with the calibration processing software and related files. The volume directory structure and contents differ slightly on the DATA and CALIBRATION volumes. Briefly, the file contents of the 2-volume scheme are found in these directories/subdirectories: DATA Volumes: CALIBRATION Volumes: ------------- -------------------- Root Root \Data \Calib \Index \Data \Document \Document \Report \Report \Catalog \Catalog \Label \Label \Extras \Index GETTING STARTED To begin using the ISS archive collection one should become familiar with the contents of the ROOT and DOCUMENT directories on both the DATA and CALIBRATION volumes. These directories include files that provide important detailed descriptive information on the ISS instrument, the archive files and formats, using the ISS team's calibration software, along with ISS team science objectives and rationale for image targeting. The Space Science Review publication released by the Imaging Team also provides important detail not found elsewhere in the archive and is a must read before embarking on analyzing the Cassini imaging data. You will find the most detailed information available on the instrument and the science objectives in this publication. This publication has not been approved for inclusion on these volumes. At the time of this writing it has been submitted, but not published (Section 1.3 Applicable Document #9). The files contained in the ROOT and DOCUMENT directories are found in various formats. The .pdf files can be read using the latest version of Acrobat Reader. If you don't have a copy, downloads are available from the internet. Some documentation files have been provided in LaTeX format. These files have a .tex extension, and are simply ASCII files that can be viewed with any text editor. They are generally human-readable, with the exception of any tables they might contain, which will not appear properly typeset unless the LaTeX file is first compiled and converted to a different format. LaTeX is free, and is currently developed and maintained by the LaTeX3 Project. Information about the system and various conversion software can be found at their current website: http://www.latex-project.org. Additionally, certain files are provided for use as human-readable files and some by home institution computer systems. For instance, the comprehensive INDEX.TAB file can be used to populate one's own image catalog for user search and query capabilities (e.g. querying for specific target names or target list, lat/lon ranges, cameras (narrow or wide), filters or selecting based on phase, incidence and emission angles). More information on the INDEX.TAB file can be found in the indxinfo.txt file in the INDEX directory. For a brief tutorial on Cassini image calibration, see the theoretical_basis.ps document, as well as section 5 of the CISSCAL manual, which can be found in the document subdirectory on the Calibration archive volume. Finally, the PDS Discipline Nodes are chartered to assist users with using the datasets they curate. Contact them for assistance if you find you have questions on getting started with using the Cassini image archive. Further details on the contents of each directory and subdirectory are found in the following section 2 paragraphs below: 2.1. Root Directory Contents Files in the Root Directory are found on both the DATA and CALIBRATION volumes. This directory includes an overview of the archive collection, a description of the data set volumes, including files for the PDS Catalog, and a list of errata or explanatory comments about the archive datasets. The contents of the ERRATA.TXT file may be updated to include important information regarding changes or modifications to the ISS datasets. Users should familiarize themselves with the contents of this file prior to accessing subsequent volumes in the archive. The DATA and CALIBRATION volumes contain the following files in the ROOT Directory: File Name Source File Contents --------- ------ -------------------------------------------------- Aareadme.TXT ISS/CICLOPS Volume content and format information with attached PDS label Errata.TXT ISS/CICLOPS A cumulative listing of comments and updates concerning all archive volumes published to date with attached PDS label Voldesc.CAT ISS/CICLOPS A description of the contents of this volume in a PDS format readable by both humans and computers ISS/CICLOPS 2.2. Data Directory Contents and Naming The Data Directory is on both the DATA and CALIBRATION volumes and contains files related to the image or calibration datasets. The EDR images are contained on the DATA volumes (including in-flight calibration images), while the sample calibrated images and the pre-flight ground calibration images are contained on the CALIBRATION volumes. Both the DATA and CALIBRATION Volumes contain an introductory datainfo.txt file, in addition to the data files. The DATA volumes contain the EDR image data files as they are generated by the Cassini Instrument Operations (IO) team [Applicable Document #3] and provided to the ISS/CICLOPS. The ISS/CICLOPS does not make any modifications to the image data files. Some modifications are made to the early mission phase PDS detached labels in order to comply with PDS standards. The EDRs are stored within CICLOPS for use by the ISS team members and the archive volume assembly process. Each EDR image data file is accompanied by its corresponding detached PDS label file. The files are organized on the archive volumes in subdirectories in SCLK order. Each subdirectory contains 128 image files and 128 image label files, for a maximum of 256 files per subdirectory (per PDS limitations). Given the fact that ISS EDR image size varies, the total number of images per volume varies. Approximately 3,000 to 5,000 images can be found on each DVD volume. The image data files (.IMG files) are organized with both the narrow angle image and its corresponding wide-angle image in the same directory. The detached labels (.LBL files) are ordered the same as the image files. The external filename of the image data file consists of a string that incorporates information about the instrument name, spacecraft clock and version number. The instrument name is required because the spacecraft clock is not unique for simultaneous exposures. The version number is required because the same image may be built multiple times due to multiple downlinks, or multiple Telemetry Data System (TDS) queries, etc. The following naming conventions are followed: Image data filename convention: _.IMG Where: camera = 1-character instrument identifier (N=NAC, W=WAC) SCLK time = 10-digit value of spacecraft clock at time of shutter close version = version number of the file Example: W1832898283_4.IMG (Wide Angle Camera image file taken at SCLK time 1832898283, version 4) The corresponding detached label file follows the same naming convention above except with ".LBL" as the extension. Example: W1832898283_4.LBL The Data Directory on the CALIBRATION volumes contains sample calibrated image data files and the ground calibration image data files. The first ten volumes contain the ground calibration images and the ISS Calibration Report, along with volume-specific directories and files. The eleventh calibration volume contains the sample calibrated images, calibration processing software, documentation and other volume-specific directories and files. The PDS Imaging Node prepared the first ten volumes for inclusion in the ISS calibration dataset. For the ground calibration files, the narrow-angle images (NAC) and the wide-angle (WAC) images have been placed in two separate subdirectories titled nacfm and wacfm. Under each of these are sub-directories for each calibration test performed. Additionally, under these are further sub-directories identifying the time range of the image files included. The image file names are labeled by SCLK of the image event. A total of 26 NAC subdirectories exist and 21 WAC subdirectories exist. Ground calibration image data filename convention: .IMG Where: SCLK time = 6-digit value of spacecraft clock at time of shutter close Example: 121811.IMG The corresponding detached label file follows the same naming convention above except with ".LBL" as the extension. Example: 121811.LBL The sample calibrated images have been processed using the Cassini Imaging Science Subsystem Calibration (CISSCAL) software included in this archive. These sample images represent what a future user of the archive should expect to achieve when performing their own calibration processing. There are ten sample calibrated images provided in the Data directory: a wide- and narrow- angle image for each of the following target types: Saturn, Rings, Titan, Icy Satellite, and Star. The following naming conventions are followed: Sample calibration image data filename convention: __CAL.IMG Where: camera = 1-character instrument identifier (N=NAC, W=WAC) SCLK time = 10-digit value of spacecraft clock at time of shutter close version = version number of the file Example: W1369916235_1_CAL.IMG (Wide Angle Camera image file taken at SCLK time 1369916235, version 1) The corresponding detached label file follows the same naming convention above except with ".LBL" as the extension. Example: W1369916235_1_CAL.LBL 2.3. Index Directory Contents The Index Directory is found on both the DATA and CALIBRATION volumes. Files in the Index Directory on the DATA volumes are provided to help the user locate images, using a variety of keywords, found on the ISS archive volumes. [Appendix A in this document provides the complete list of keywords provided in the INDEX.TAB files contained on the DATA volumes.] Some of this keyword information comes directly from the detached PDS image EDR label; for example, keywords such as FILE_NAME, DATA_CONVERSION_TYPE, IMAGE_MID_TIME, FILTER_NAME, etc. The remaining keywords come from CICLOPS-delivered image data processing software which calculates many geometric quantities and target information (e.g., TARGET_DISTANCE, PIXEL_SCALE, PHASE_ANGLE, TWIST_ANGLE, etc.). The index file consists of fixed-length records in ASCII character format. Each line is a record containing all the keywords for a particular image on the volume. Fields in a record are delimited by commas. Non-numeric fields are enclosed in quotes and left-justified, whereas numeric fields are not enclosed by any characters and are right-justified. Multi-valued fields are enclosed in brackets and a comma separates each item in that field. The accompanying label file, INDEX.LBL, details the keyword name, data type, start byte, number of bytes, and format so that keywords can be easily looked up and the file can be properly read into a database. The DATA volumes contain the following files in the Index Directory: File Name Source File Contents --------- ------ -------------------------------------------------- Indxinfo.TXT ISS/CICLOPS A description of the contents of this directory with attached PDS label Index.TAB ISS/CICLOPS A table listing related to data products and image geometry on this volume Index.LBL ISS/CICLOPS A PDS detached label that describes INDEX.TAB The CALIBRATION volumes containing the ground calibration image files also contain an Index Directory. Also, a comma-delimited ASCII file, this index file provides one record for each image file found on the DVD volume. These ground calibration image volumes also contain a CUMINDEX.TAB and .LBL file that provides of cumulative listing for the specific file contents for all volumes created. The following files are contained in the Calibration volume Index Directory: File Name Source File Contents --------- ------ ------------------------------------------------ Indxinfo.TXT PDS Imaging Node A description of the contents of this directory, including notes on using the index files on these volumes Index.TAB PDS Imaging Node A table listing related to data products and image geometry on this volume Index.LBL PDS Imaging Node A PDS detached label that describes INDEX.TAB 2.4. Document Directory Contents The Document Directory is found on both the DATA and CALIBRATION volumes. However, the contents differ between volumes. Both Document Directories contain a Report(s) subdirectory, as well. The Document Directory on the DATA volumes contains the SIS documents related to the EDR data products and the archive volumes. These documents generally describe the contents, formats and naming conventions for the data products. DATA volumes contain following files in the Document Directories: File Name Source File Contents --------- ------ ------------------------------------------------ Docinfo.TXT ISS/CICLOPS A description of the contents of this directory Archsis.TXT ISS/CICLOPS The Archive Volume SIS (this document) as text Archsis.PDF ISS/CICLOPS The Archive Volume SIS as a PDF Archsis.LBL ISS/CICLOPS A PDS detached label that describes both ARCHSIS.TXT and ARCHSIS.PDF Edrsis.TXT ISS/CICLOPS The Experiment Data Record Tour Phase SIS as text Edrsis.PDF ISS/CICLOPS The Experiment Data Record Tour Phase SIS as a PDF Edrsis.LBL ISS/CICLOPS A PDS detached label that describes both EDRSIS.TXT and EDRSIS.PDF A Report Subdirectory contains two different data outages and gap reports. As provided by IO, these reports detail the quality assessments and quantitative summaries for the image telemetry and subsequent image data product generation. They provide detail on the status of the downlink, noting any missing or incomplete data products and the reason for the discrepancy. A preliminary version of these reports is generated for immediate analysis just after the first version of the products are generated, approximately 4-5 hours after the end of the downlink pass. Within 12 days, IO/MIPS reconciles the data through a process of identifying, explaining and tracking any missing data, where possible. Once this reconciliation process is complete, the final reports are generated, as well as the final EDR images. NOTE: no product and quality reports were generated for images prior to SCLK 1431917000. The quality report consists of one to three tables; depending on whether there are missing or incomplete products. The first table lists information about all the predicted products for the time range covered in the report. This information includes the following: FILENAME: Filename of the product. OBSERVATION_ID: Planned observation from which product originated. SEQUENCE_NUMBER: The order the image appears in the observation. COMMAND_FILE_NAME: Camera commanding file name for this product. ORDER_NUMBER: The order the image appears in the IOI file. SCETSTOP - The image stop time in UTC. If there are partial/incomplete products, a second table is given describing those products. This table consists of the following: FILENAME: Filename of the product. DATA_POL: Images truncated due to data policing. DSN_GAP: Images not received or partially received due to DSN issue. TRUNC_RO: Images truncated due to a short readout cycle. UNEXPLAINED: Incomplete images where the reason is unknown. The following columns are used to explain incomplete images: 'PARTIAL' means that an image was received, but is incomplete due to the problem at the top of that column. 'NO' means that while the image is incomplete, it is not caused by the problem characterized by that column. 'NULL' means that either analysis is not complete for that column/image, or an explanation has been given but further reconciliation will not be performed. If there are missing products, a third table is given describing those products. This table consists of the following: SCLKSTOP: Spacecraft clock time of image stop time. CAMERA: Camera taking this image, NAC or WAC. TRIGGER: Trigger number issued to camera for this image. TRIGGERTIME: Spacecraft clock of trigger execution time. OFFSET: Offset of image time from trigger execution time. PEF: Predicted Events File for this product. IOI: Filename of camera commanding file (IOI) for this product.. REASON: Reason for missing product if known. The Product Report contains statistical product generation information in paragraph form. The information includes the following: Number of FINAL and COMPLETE products Number of FINAL and INCOMPLETE products Number of incomplete products due to TRUNCATED READOUT Number of incomplete products due to DATA POLICING and DSN GAPS Number of PRELIMINARY and COMPLETE products Number of PRELIMINARY and INCOMPLETE products Number of preliminary and incomplete products due to DATA POLICING and DSN GAPS Number of MISSING products Number of missing products due to DATA POLICING and due to DSN GAPS Number of UNPREDICTED products A Quality and a Product report are generated for the NAC and WAC each for a total of four reports covering the images on the volume. The Product and Quality reports are labeled as follows: __.rpt Examples: COISS_2001_nac_quality.rpt COISS_2001_nac_product.rpt COISS_2001_wac_quality.rpt COISS_2001_wac_product.rpt Found in the DOCUMENT Directory on the CALIBRATION volumes is a Report subdirectory containing the ISS Calibration Report that provides detailed information regarding ISS calibration and the calibration algorithms used to produce the calibration data files. This is a 'must-read' document for any users wishing to thoroughly understand the ISS instrument calibration process and specifics. Report subdirectory files for the Calibration volumes include: File Name Source File Contents --------- ------ ----------------------------------------------- ISSCALRPT.HTM PDS Imaging Node ISS Calibration Report as hypertext ISSCALRPT.LBL PDS Imaging Node A PDS detached label that describes the ISS Calibration Report PDS Imaging Node The DOCUMENT Directory on the remaining CALIBRATION volumes contains documentation related to using the ISS-produced calibration processing software (see EXTRAS section 2.8 for further discussion on the ISS calibration processing software). The following files are found in the CALIBRATION volumes beginning with Volume 11: File Name Source File Contents --------- ------ -------------------------------------------- Cisscal_v3_manual.TEX ISS/CICLOPS ISS Calibration Software User Guide in LaTex Cisscal_v3_manual.PDF ISS/CICLOPS (PDF version) Cisscal_v3_manual.LBL ISS/CICLOPS (detached label) In_flight_cal.TEX ISS/CICLOPS ISS In-Flight Calibration Guide in LaTex. In_flight_cal.PDF ISS/CICLOPS (PDF version) In_flight_cal.LBL ISS/CICLOPS (detached label) Theoretical_basis.TEX ISS/CICLOPS ISS Calibration Theoretical Basis in LaTex Theoretical_basis.PDF ISS/CICLOPS (PDF version) Theoretical_basis.LBL ISS/CICLOPS (detached label) NOTE: .pdf files are known to be problematic when using LINUX Acrobat Reader. 2.5. Catalog Directory Contents The files in the Catalog Directory provide a top-level understanding of the mission, spacecraft, instruments, and data sets. This directory is found on both the DATA and CALIBRATION volumes. The Catalog Directory contains the following files: File Name Source File Contents --------- ------ ---------------------------------------------- Catinfo.TXT ISS/CICLOPS Description of the contents of this directory Jupiterds.CAT ISS/CICLOPS Jupiter data set information for the PDS catalog, including science paper references (Jupiter data set volumes only) Saturnds.CAT ISS/CICLOPS Saturn data set information for the PDS catalog, including science paper references (Saturn data set volumes only) Calds.CAT ISS/CICLOPS Calibration data set information for the PDS catalog, including reference to the ISS Calibration Report (Calibration volume only) Insthost.CAT Cassini Engineer Instrument host (i.e., spacecraft) information for the PDS catalog Issna_inst.CAT ISS/CICLOPS Instrument description reference for Narrow Angle Camera for the PDS catalog Isswa_inst.CAT ISS/CICLOPS Instrument description reference for Wide Angle Camera for the PDS catalog Mission.CAT Cassini Engineer Mission information for the PDS catalog Person.CAT ISS/CICLOPS Personnel information for the PDS catalog (Team and PDS personnel responsible for generating the archive) Projref.CAT Cassini Engineer References mentioned in INSTHOST and MISSION .cat files Issref.CAT ISS/CICLOPS References mentioned in other *.CAT files and/or pertinent to the ISS archive collection 2.6. Label Directory Contents The Label Directory contains additional 'include' files that are not packaged with the data products or elsewhere in the volume directories. Include files are files referenced by a pointer in the EDR PDS label. They contain additional metadata or descriptive information regarding the datasets. The Label Directory is found on both the DATA and CALIBRATION volumes. The following files can be found in the Label Directory: File Name Source File Contents --------- ------ ----------------------------------------------- Labinfo.TXT ISS/CICLOPS A description of the contents of this directory Tlmtab.FMT IO/MIPS Binary Telemetry Header Format Prefix.FMT IO/MIPS Binary Line Prefix Format Prefix16.FMT IO/MIPS Binary Line Prefix Format Prefix2.FMT IO/MIPS Binary Line Prefix Format Prefix3.FMT IO/MIPS Binary Line Prefix Format Vicar2.TXT IO/MIPS ASCII VICAR Label Format 2.7. CALIBRATION Directory Contents The CALIB directory is found only on volume eleven of the CALIBRATION data set. This directory contains the calibration data files produced by the ISS team. These files range in format from text files (filter transmission functions, QE functions, etc.) to VICAR image files (blemish pixel maps, bright-dark pixel pair maps, flatfields, etc.), to Tagged Image File Format (TIFF) images and assorted binary-format data files. The contents of the CALIB directory will be periodically updated throughout the life of the mission as knowledge of the instrument improves. As new files are provided, or old files are modified or deleted, explanations of changes will be added to the ERRATA.txt file. The calibration data files are divided into subdirectories based on function. All .txt files contain an attached PDS label. VICAR-format calibration files are accompanied by detached PDS labels. The CALIB subdirectories and files, as of this writing, are as follows: Subdirectory Function Description (and files) ------------ -------------------------------- Antibloom VICAR image files identifying anti-blooming pixel pairs for NAC and WAC. (abpair_mask.na, abpair_mask.wa) Bitweight Text files needed for performing bitweight correction. (wacg2m10.bwt, wacg3p25.bwt, nacg1p5.bwt, nacg3m10.bwt, wacg1m10.bwt, wacg2p25.bwt, wacg3p5.bwt, nacg2m10.bwt, nacg3p25.bwt, wacg1p25.bwt, wacg2p5.bwt) Correction Derived correction coefficients for NAC and WAC. (correctionfactors.1.old, correctionfactors_qecorr.1, wac_qe_correction.tab, nac_qe_correction.tab) Darkcurrent Dark current coefficient files and dark current VICAR image files derived from them. (Darkcurrent file names: TBD) Efficiency Various text files for calculating integrated system efficiencies. (ccdqe.dat, effic.db.old, solarflux.dat, effic.db, na_optics.dat, solarflux.dat.old, wa_optics.dat) Efficiency/Systrans Text files containing system transmissions for each filter combination, as well as a text file describing the column headings. (CAMERA-FW1-FW2.systrans, e.g. ISSNAIR2UV3.systrans) Flatfield VICAR image slope files, additional VICAR image dustring and mottle correction files, and a couple database text files. (Flatfield filenames: TBD) Offset VICAR image files for applying shutter offset, as well as explanatory text files. (nacshutter.txt, so.nacfm_plus25 so.wacfm_minus10, so.wacfm_plus5 so.nacfm_minus10, so.nacfm_plus5, so.wacfm_plus25, wacshutter.txt) In addition, the Calib directory will also feature a g-zipped TAR archive containing all the Calib subdirectories and their contents listed above. 2.8. Extras Directory Contents Found only on volume 11 of the CALIBRATION data set, this directory is reserved for elements that are beyond the scope of the PDS archive requirements and are not considered critical to understanding the dataset, but useful. The PDS places no restrictions on the contents and organization of this subdirectory other than conformance to ISO-9660/UDF standards. The Extras directory contains the source code for the Cassini Imaging Science Subsystem Calibration (CISSCAL) software. This software, developed by the Cassini Imaging team, allows the user to radiometrically and geometrically process the EDR-level images into higher level calibrated images. CISSCAL was developed using the Interactive Data Language (IDL); IDL Version 5.5 or later is required to compile and run the code. Both the CISSCAL software, and the calibration data files that are necessary to run it (found in the calib subdirectory of the eleventh volume of the Calibration data set) will be updated throughout the mission, and the updates provided on subsequent Calibration volumes as they become available. Note that, in the case that your computer system reads the ISO file system (instead of the UDF file system) of the calibration DVD volume, filenames may display as uppercase instead of the default lowercase. This will make the CISSCAL software unusable, as IDL requires lowercase filenames. To get around this issue, the entire contents of the CISSCAL subdirectory have also been provided as a g-zipped TAR archive. These archives can be decompressed using the standard 'tar' and 'gunzip' commands included with most LINUX and UNIX distributions, or with a program like WinZip for users running Windows. The following files are contained in the Extras Directory: File Name Source File Contents --------- ------ ---------------------------------- Extrinfo.TXT ISS/CICLOPS A description of the contents of this directory with attached PDS label cisscal.tar.gz ISS/CICLOPS Entire contents of CISSCAL subdirectory in a g-zipped TAR archive cassimg__bitweightcorrect.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__brightdark.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__correctionfactors.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__debias.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__define.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__dividebyareapixel.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__dividebyefficiency.proISS/CICLOPS CISSCAL source code written in IDL cassimg__dividebyexpot.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__dividebyflats.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__dntoelectrons.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__dustringcorrect.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__geomcorr.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__linearise.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__radiomcalib.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__readlabels.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__readvic.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__subtractdark.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__twelvebit.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__twohz.pro ISS/CICLOPS CISSCAL source code written in IDL cassimg__writevic.pro ISS/CICLOPS CISSCAL source code written in IDL casslabels__define.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_common.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_delut.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_gui.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_log.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_readlist.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_readspec.pro ISS/CICLOPS CISSCAL source code written in IDL linetime.pro ISS/CICLOPS CISSCAL source code written in IDL cisscal_v3_manual.pdf ISS/CICLOPS CISSCAL manual in PDF format readme.txt ISS/CICLOPS CISSCAL readme file in TXT format 3. Archive Volume Format This section describes the format of the ISS archive volumes as assembled and written on archive media by ISS/CICLOPS and then transferred to the PDS Imaging Node. Data that comprise the archive are formatted in accordance with Planetary Data System specifications [Applicable Documents 4 and 5]. It should be noted that every attempt has been made to stay consistent in case sensitivity when naming directories, subdirectories and file names. Directory file names are found in uppercase, however, mixed cases are found in file names resulting from software-specific dependences. 3.1. File Formats This section describes file formats for the types of files contained on the ISS archive volumes. 3.1.1. Document File Format Document files with the .TXT suffix exist in the Root, Index, Document, Calilb, Catalog, Label, and Extras directories. They are flat ASCII text files, which may have embedded PDS labels. PDS recommends plain text files have line length restricted to 78 characters or fewer, to accommodate printing and display on standard devices. Each line is terminated by the two- character carriage-return/linefeed sequence, (ASCII decimal character codes 13 and 10, respectively), for a maximum total line length of 80 characters. Document .TXT files may be accompanied by corresponding document files with .HTM, .TEX or .PDF suffixes in the Root and Document directories. There may be documents that contain formatting and figures that cannot be rendered as ASCII text. Therefore each document may be available in two formats, hypertext and PDF. The hypertext file contains ASCII text plus hypertext markup language (HTML) commands that enable it to be viewed in a Web browser such as Netscape Navigator or Microsoft Internet Explorer. The hypertext file may be accompanied by ancillary files such as images and style sheets that are incorporated into the document by the Web browser. The second format, PDF (Portable Document Format) is a proprietary format of Adobe Systems Incorporated that is frequently used for distributing documents. Adobe offers free software, Acrobat Reader, for viewing PDF files. Files may also be formatted in LaTeX, a TeX macro package. LaTeX is a high-quality typesetting system, with features designed for the production of technical and scientific documentation. 3.1.2. Tabular File Format Tabular files (.TAB suffix) exist in the Index Directory. Tabular files are ASCII files formatted for direct reading into many database management systems on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks ("). (Character fields are padded with spaces to keep quotation marks in the same columns of successive records.) Character fields are left justified, and numeric fields are right justified. The "start byte" and "bytes" values listed in the labels do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage-return/line feed character sequence, . This allows a table to be treated as a fixed length record file on computers that support this file type and as a text file with embedded line delimiters on those that don't. All tabular files are described by detached PDS labels. The PDS label file has the same name as the data file it describes, with the extension .LBL; for example, the file INDEX.TAB is accompanied by the detached label file INDEX.LBL in the same directory. 3.1.3. PDS Label Format All image data files in the archive have detached PDS labels. These PDS labels are object-oriented. The object to which the label refers (e.g. IMAGE, TABLE, etc.) is denoted by a statement of the form: ^object = location in which the carat 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 of the object (the first record in the file is record 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: ^IMAGE = ("N1294562651_1.IMG",3) indicates that the IMAGE object begins at record 3 of the file N1294562651_1.IMG, 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 ^object = "filename.ext" ^object = ("filename.ext",n) ^object = ("filename.ext",n ) where: n starting record or byte number of the object, counting from beginning of the file (record 1, byte 1); default is record number. indicates that number given is in units of bytes. filename upper-case file name. ext upper-case file extension. A combination of detached and attached PDS labels are found throughout the archive volumes. For further explanation of the PDS labels for each type of data product, see the Data Product SIS, edrsis.txt, in the Document directory [Applicable Document #3]. 3.1.4. Software File Format The Cassini ISS calibration software (CISSCAL) has been developed by the Cassini Imaging team using IDL software. No compiled executables are supplied. Source code is written in IDL such that Version 5.5 or later is required to run CISSCAL. The source code is machine independent and will thus run on any machine for which an appropriate version of IDL is available. 3.1.5. Catalog File Format Catalog files (suffix .CAT) exist in the Catalog and Root directories. They are text files formatted in an object-oriented structure consisting of sets of 'keyword=value' declarations. Each line must be terminated by the two- character carriage-return/linefeed sequence, (ASCII decimal character codes 13 and 10, respectively). PDS recommends catalog files have line length restricted to 72 characters or fewer, including the , to accommodate PDS data ingestion requirements set forth by their internal catalogs and databases. 3.1.6. Science Data File Formats The image processing software used to create the EDR image data files is called VICAR (Video Image Communication And Retrieval). VICAR is an entire system of software, formats, and procedures for image storage and processing and was developed and is maintained by JPL's MIPS. A full explanation of VICAR, its standards, its software and reference information can be found at website: http://www-mipl.jpl.nasa.gov/vicar/. Each image data file has a filename ending with the '.IMG' suffix, and contains several fixed-length data records. These are: the ASCII VICAR Label (or simply "image header"), the Binary Label Header (or "Binary Telemetry Header"), and the Image Line Records, which are comprised of the Binary Line Prefix plus the actual pixel data. All of these are briefly described in the paragraphs below. For more complete information about the format and content of the image data products, see the Cassini ISS Software Interface Specification (SIS) documents found in the Document directory of these volumes. These image files are reconstructed from the best available telemetry data and line-filled where necessary to produce the most complete image records possible. The ASCII VICAR Label is included to facilitate image processing and allow easy validation of products using existing VICAR software. These labels consist of a set of ASCII "keyword=value" pairs describing the important characteristics of the image. The VICAR Label is designed to be human-readable because it often is used to annotate products derived from the image, such as prints or plots. In addition, it is maintained through the various processed versions of the image to allow traceability. Also, the Label items may be extracted by software modules in order to guide automated processing procedures. The VICAR Label contains required System items (such as image size information), History items (recording processing history for the file), and optional Property items (such as items describing gain states, etc.). The Binary Label Header (also known as the Binary Telemetry Header) contains machine-readable information about the image as a whole and is populated directly from the telemetry available for the product. Many of these items are in the VICAR Label as well, but non-VICAR sites may ignore the VICAR Label and use the Binary Telemetry Header to construct their own human-readable label. This record contains 60 bytes of information and is padded with zeros to the image record length. Items in this header are copied directly from the Extended ISS Science header returned in telemetry. There is one Line Record for each image line, comprised of a 24-byte Binary Prefix followed by the 8- or 16-bit pixel data for that line. The Prefix contains information about the image line derived from telemetry. This information may vary from line to line, so is not appropriate to include in the Binary Telemetry Header. Note that for Lossy compressed images, the data are not associated with lines, so there is no way to associate a given record with a line number. In this case, the Binary Line Prefix contains information extracted from the lossy records received. 4. Archive Volume Generation 4.1. Data Transfer Methods and Archive Volume Creation Once an image is transmitted back to the Deep Space Network (DSN) and sent on to the Telemetry Data System (TDS) JPL, it is reformatted by the IO/MIPS from a series of data packets back into a two dimensional image. In the reformatting process, the upper 1s in 16-bit unconverted, uncompressed data are converted to 0s. Images that had been compressed, either lossless or lossy, are automatically decompressed in the reconstitution process before being sent to ISS/CICLOPS where they are ingested into the Archive Database, from which this archive is built. Preliminary (quick-look) versions of images are generated immediately and distributed for instrument performance analysis. IO then performs reconciliation, if there is missing data in the preliminary versions, in an attempt to make more complete products. Once reconciliation is performed (within two weeks from downlink time), a final version of the image is produced. Only final image versions are archived on these volumes. If images have been converted down to 8-bits by the LUT, a reverse LUT is applied to them to restore them to their approximate full 12-bit values. (This is an option in the Cassini ISS Calibration (CISSCAL) software that is supplied in this archive.) There is no way to restore an image previously converted to the 8 lowest bits back to 12-bits unless one is confident of smooth gradients throughout the image. Further modifications can take place to clean them and convert them to physical units in the process of calibration. Images are put on the archive volumes exactly as they are received from IO/MIPS. The only processing that is done is to auto-navigate the images and assemble the archive volumes. Automated software is used to generate the archive disks by selecting the appropriate range of images, gathering the static documentation, and generating the INDEX.TAB file from the auto-navigation results. Auto-navigation software (Autonav) was developed to perform the large task of image pointing refinement (c-smithing) for the hundreds of thousands of images taken by the ISS cameras. Autonav uses an array of object detection algorithms in conjunction with the most recent spacecraft position and orientation kernels to navigate the images. The output of Autonav for any particular navigated image is a single, discrete c-kernel for the image mid time. These c-smithed c-kernels are packaged up in larger time periods and delivered to the Cassini project's database and JPL's NAIF node. Though the success rate of Autonav is high, it is not 100% successful. The code was structured to minimize the number of false-positive navigations. So, in many cases, some images that seem navigable, will fail to meet the success thresholds built into Autonav. In order to validate Autonav results, a tool was developed to allow a final reviewer to quickly visually scan through Autonav results and look for false-positive navigations and approve those that look correctly navigated. Also, a c-kernel compare tool is used to compare the auto-navigated c-kernels against the ACS reconstructed c-kernels and flag large discrepancies between the two for further investigation. However, all of these thresholds and verification steps do not absolutely prevent Autonav from producing false results, so future users are warned to exercise caution with respect to these results. Autonav results, when accurate, will greatly improve the accuracy of the geometric quantities calculated for the INDEX.TAB file. One DVD copy is sent to the PDS Imaging Node, at JPL and one is retained within CICLOPS. The PDS Imaging Node creates two additional DVD copies for dissemination, validation and retention by the PDS Central Node and the National Space Science Data Center (NSSDC). Archive volume submissions are recorded and tracked through the use of the Cassini Archive Tracking System (CATS). 4.2. Validation Methods Validation is the method by which data sets and volumes are verified to be in accordance with the standards identified in the Planetary Data System Standards Reference document [Applicable Document #5]. Validation is considered to have 2 aspects: 1) quality scientific usability and 2) technical compliance to PDS standards. In order to ensure PDS-compliant products, the archive volumes are validated by a collaborative effort between the ISS/CICLOPS team, the Imaging and Central Nodes of the PDS, and non-Cassini imaging scientists. The ISS/CICLOPS team is responsible for producing PDS-compliant archive volumes, while the PDS personnel are responsible for ensuring that the archive volume(s) meet PDS standards. Validation is performed on each volume by PDS using their validation tools. ISS/CICLOPS-developed operational volume verification tools and procedures are also utilized prior to delivery to PDS Imaging Node. Together these verification checks ensure PDS-compliant archive volumes. Scientific usability is assessed through the ISS science team's normal and routine use of the mission imaging data sets in their science analysis. Additionally imaging scientists not associated with the Cassini project participate in the archive volume peer review process where they verify the "science" content of the data set, the completeness of the documentation, and the scientific validity (i.e., the integrity and usability) of the data. A peer review of sample volumes is conducted by PDS. These reviews serve to validate the volume for proper structure, format, completeness, and science usability. Any deficiencies in the reviewed archive volume found are corrected and resolved. When all correctable errors have been resolved, production of the archive volumes proceeds and further validation is performed on a spot check basis by the both the PDS and the ISS/CICLOPS team. Non-correctable errors (e.g., an error in the downlink data file) is described in the evolving errata file, ERRATA.TXT, included on each archive volume in the Root Directory 4.3. Data Product Sizes and Delivery Rates All ISS standard product archive volumes will be delivered to the PDS Imaging Node consistent with the quarterly archive delivery schedule presented in the Cassini Huygens Program Archive Plan for Science Data (PD 699-069; JPL D-15976). Table 2 below summarizes expected sizes and production rates for the ISS Standard Products. Table 2 - Standard Product Sizes and Delivery Rates Data Set ID Product Production Rate Expected Expected Size* #products data vol ------------------------------- ------- --------------- --------- --------- CO-CAL-ISSNA/ISSWA-2-CAL-V1.0 Varies Quarterly rls TBD TBD CO-E/V/J-ISSNA/ISSWA-2-EDR-V1.0 1.5 Mb 140 images/day 32,000 32 Gb CO-S-ISSNA/ISSWA-2-EDR-V1.0 1.5 Mb 300 images/day 440,000 660 Gb *average image size is used for calculation For more information about the Cassini data products release schedule, see Appendix B of the Cassini/Huygens Program Archive Plan for Science Data [Applicable Document 2]. 4.4. Archive Media Characteristics All ISS standard product archive volumes have a Digital Versatile Disk (DVD-R) format that is produced in UDF-Bridge format (Universal Disc Format) with ISO 9660 level 2. Backup and Duplicates Following transfer of the assembled physical archive DVD volumes from the ISS/CICLOPS to the PDS Imaging Node, the virtual volumes are stored on magnetic media by the ISS/CICLOPS at least through the generation of the archive media. 4.5. Labeling and Identification The Cassini ISS identification and labeling schemes are divided according to Jupiter (cruise), Saturn (tour) and Calibration. Naming conventions and labeling schemes are: DATA_SET_ID: CO_E/V/J_ISSNA/ISSWA_2_EDR_V1.0 CO_S_ISSNA/ISSWA_2_EDR_V1.0 CO_CAL_ISSNA/ISSWA_2_EDR_V1.0 DATA_SET_NAME: CASSINI ORBITER EARTH/VENUS/JUPITER ISSNA/ISSWA 2 EDR V1.0 CASSINI ORBITER SATURN ISSNA/ISSWA 2 EDR VERSION 1.0 CASSINI ORBITER CALIBRATION ISSNA/ISSWA 2 EDR VERSION 1.0 STANDARD_DATA_PRODUCT_ID: ISS_E/V/JEDR ISS_SEDR ISS_CAL VOLUME_SERIES_NAME: MISSION TO SATURN VOLUME_ID: COISS_xxxx (where first x = 1 for Jupiter, 2 for Saturn, 0 for calibration) (where next xxx = sequential numbering of volumes starting with 001) VOLUME_NAME: CASSINI ISS EARTH/VENUS/JUPITER EDR SCLK 1294561143 to SCLK 1451040707 CASSINI ISS SATURN EDR SCLK 1454725799 to SCLKXXXXX CASSINI ISS CALIBRATION FILES VOLUME_SET_ID: USA_NASA_PDS_COISS_xxxx (where first x = 1 for Jupiter, 2 for Saturn, 0 for calibration) (where next xxx = sequential numbering of volumes) VOLUME_SET_NAME: CASSINI ISS EXPERIMENT DATA RECORDS AND CALIBRATION FILES VOLUME_VERSION_ID: VERSION x (where x represents each volume version numbered sequentially starting with the original volume as 1) VOLUMES: XXX (where xxx represents the total number of volumes in the Cassini ISS Experiment Data Records and Calibration Files volume set) The following table provides examples of this scheme: Mission Volume_Set_ID Volume_ID Volume_Name Phase ------- ----------------------- ---------- ------------------------------- All USA_NASA_PDS_COISS_Onnn COISS_0nnn Cassini ISS Calibration Files Jupiter USA_NASA_PDS_COISS_1nnn COISS_1nnn Cassini ISS Earth/Venus/Jupiter Experiment Data Record Saturn USA_NASA_PDS_COISS_2nnn COISS_2nnn Cassini ISS Saturn Experiment Data Record 5. Support Staff and Cognizant Persons Carolyn Porco ISS Team Lead Leslie Pieri ISS Archive Lead Josh Riley ISS/CICLOPS Ops Team Deputy/Downlink Engineer Ben Knowles ISS/CICLOPS Calibration & Archiving Engineer Charles Avis ISS Instrument Operations Task Lead Diane Conner Cassini Project Archive Coordinator Steve Adams PDS Central Node Cassini Data Engineer John Diehl PDS Imaging Node Representative 6. Appendices Appendix A provides a table listing all keywords found in the ISS archive volume INDEX.TAB files. Included in the table, in addition to the keyword, is the source of the value and the valid values as determined within the ISS archive generation process. Additionally, included are the PDS valid values as defined by PDS. Discrepancies may exist. In those cases, it should be noted that the PDS label, as generated by IO/MIPS, is not modified in the ISS archive generation process and, hence, these keywords are identified exactly as they are generated for the detached PDS label accompanying the EDR. As a guideline, all valid values identified by "inf" and "-inf" can be replaced with corresponding max and min values allowed for corresponding data type. For example, if the DATA TYPE is "real", you can replace all "inf" values with "1e+32" and all "-inf" with "-1e32". A bracket,"[" or "]", means that value is inclusive. A parenthesis, "(" or ")" means that value is excluded. For example, [-90, 90] is the equivalent of value >= -90 AND value <= -90. (-90, 90) is the equivalent of value > -90 AND value < -90. APPENDIX A - ISS KEYWORDS TABLE (see ARCHSIS.PDF)