CCSD3ZF0000100000001NJPL3IF0PDS200000001 = SFDU_LABEL RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 SPACECRAFT_NAME = MAGELLAN TARGET_NAME = VENUS OBJECT = TEXT PUBLICATION_DATE = 1992-02-01 BYTES = 80 NOTE = "Magellan GxDR CD-ROM" END_OBJECT = TEXT END MAGELLAN GxDR CD-ROM 1. Introduction Overall, the collection of Magellan CD-ROMs contains three data sets. One is the GxDR data set, consisting of MIT Altimetric and Radiometric Global Data Records: the Global Topography Data Record (GTDR), Global Emissivity Data Record (GEDR), Global Slope Data Record (GSDR), and Global Reflectivity Data Record (GREDR). Another data set contains the Altimetry and Radiometry Composite Data Record (ARCDR) from MIT. The third data set is the MIDR (Mosaic Image Data Record) a collection of high-resolution radar backscatter images from JPL. This CD-ROM contains MIT Altimetric and Radiometric Global Data Record and associated documentation. The complete data set includes GTDR, GREDR, GSDR, and GEDR, i.e. global images of Venus in which the data values represent topography, radar reflectivity, meter-scale surface slope, and microwave emissivity. For each data type, the planet is presented in four map projections: sinusoidal, Mercator, and north and south polar stereographic. In addition, the sinusoidal topography image (GTDR) is accompanied by a "radius error" image. The volume also contains documentation and index files to support access and use of the images. The Mercator and sinusoidal images cover the entire planet. The sinusoidal images are centered on each pole and extend to +-33 degrees latitude in the corners. The mapping scale is the same for each image--each sinusoidal pixel subtends 360/8192 deg., or about 4.641 kilometers, and this is also true for equatorial pixels in the Mercator images and for polar pixels in the stereographic images. This is explained more fully in the DSMAP.LBL file in the [LABEL] directory. All data formats are based on the Planetary Data System Data Preparation Workbook ("PDS Data Preparation Workbook, D-7669. May 1991.) and are similar to the formats used in generating the Voyager CD-ROM set ("Voyagers to the Outer Planets", volumes 1-8, Planetary Data System, JPL, 1989). 2. Disk Format The disk has been formatted so that a variety of computer systems (e.g. IBM PC, Macintosh, Sun, VAX) may access the data. Specifically, the disk is formatted according to the ISO 9660 level 1 Interchange Standard, and file attributes are specified by Extended Attribute Records (XARs). For computer software that fully supports XARs, access to the CD-ROM volume will be straightforward; the disk will appear to the user to be identical to a file system of directories, sub- directories, and data files. Some computer systems that do not support XARs will ignore them; others will append the XAR to the beginning of the file. In the latter case the user must ignore the first 512 bytes of the file. For further information, refer to the ISO 9660 Standard Document: RF# ISO 9660-1988, 15 April 1988. 3. File Formats Each GxDR is divided into two arrays of 32 framelets (in sinusoidal and Mercator map projections) arranged in four rows and eight columns, and two arrays of 4 framelets (in north and south polar stereographic projections) arranged in two rows and two columns. The GTDR contains a fifth array of 32 framelets holding the "radius error image" (in a sinusoidal map projection). The framelets are numbered in increasing order from left to right, top to bottom. Each framelet is stored in a separate file. A framelet is 1024 lines by 1024 samples. The GREDR, GSDR, and the GTDR radius error image use one byte per sample, whereas the GEDR and the remaining GTDR images, with their greater dynamic range, use two bytes per pixel. The framelet files contain embedded VICAR2 labels and have detached PDS labels. The framelet files and supplementary data files for each GxDR are stored in a separate subdirectory. Additional general information about each product is found in the [LABEL] directory. The *.LBL files in that directory contain the PDS catalog information for the Magellan Mission, the spacecraft, the radar instrument, and the data sets. Further information on GxDR products can also be obtained from the Magellan Software Interface Specification (SIS) document "Global Altimetry and Radiometry Data Record", MIT-MGN- GxDR, version 2.1, October 21, 1991. A copy of this document is located in the [DOCUMENT] directory of this disk, in the file named GXDR.TXT. Browse versions of the GxDRs are provided for quick inspection of the images. The browse version of each GxDR is found in the sub- directory for that GxDR. The file name for the browse image is BROWSE.IMG. Each browse image of a 32-framelet image is 512 lines by 1024 samples, and was created by averaging groups of 8x8 pixels in the original 4096x8192 GxDR frame. Each browse image of a 4-framelet image is 1024 lines by 1024 samples and was created by averaging groups of 2x2 pixels in the original 2048x2048 GxDR frame. Browse images contain embedded VICAR2 labels and have detached PDS labels. Files in the [SOFTWARE] directory are intended to be used in specific environments -- MS-DOS, MacOS, and UNIX/X11. They are not necessarily useful, or even readable, within other operating systems. All document files and detached label files contain 80-byte fixed- length records, with a carriage return character (ASCII 13) in the 79th byte and a line feed character (ASCII 10) in the 80th byte. This allows the files to be read by the MacOS, DOS, Unix, and VMS operating systems. All tabular files are also described by PDS labels, either embedded at the beginning of the file or detached. If detached, the PDS label file has the same name as the data file it describes, with the extension .LBL; for example, the file GCONTENT.TAB is accompanied by the detached label file GCONTENT.LBL in the same directory. The detached labels for MIDRs and GxDRs also contain PDS-defined map projection keywords that provide information needed to extract latitude and longitude values from given line and sample locations. Tabular files are formatted so that they may be read directly 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 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 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. 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. In an embedded label, the location is an integer representing the starting record number of the object (the first record in the file is record 1). In a detached label, the location denotes the name of the file containing the object, along with the starting record or byte number if there is more than one object. For example, ^IMAGE_HEADER = ("F02.IMG",1) ^IMAGE = ("F02.IMG",3) indicates that the IMAGE object begins at record 3 of the file F02.IMG, in the same directory as the detached label file. Below is a list of the possible formats for the ^object definition. ^object = n ^object = n ^object = ("filename.ext") ^object = ("filename.ext",n) ^object = ("[dirlist]filename.ext",n) ^object = ("filename.ext",n) ^object = ("[dirlist]filename.ext",n) where n is the starting record or byte number of the object, counting from the beginning of the file (record 1, byte 1). indicates that the number given is in units of bytes. filename is the upper-case file name, before the decimal point. ext is the upper-case file name, after the decimal point. dirlist is a period-delimited path-list of parent directories, in upper case, that specifies the object file directory. The list begins on directory level below the root directory of the CD-ROM. '[dirlist]' may be omitted when the object being described is located either in the same directory as the detached label or in a sub-directory named 'LABEL', located one level below the CD-ROM root directory. 4. CD-ROM Contents The files on this CD-ROM are organized in one top-level directory with several subdirectories. The following table shows the structure and content of these directories. In the table, directory names are enclosed in square brackets ([]), upper-case letters indicate an actual directory or file name, and lower-case letters indicate the general form of a set of directory or file names. FILE CONTENTS |- AAREADME.TXT This text file. | |- GCUMCOMM.TXT A description of known errors and anomalies in | this and ALL previous Magellan GxDR CD-ROM | disks. | |- VOLDESC.SFD A description of the contents of this CD-ROM | volume in a format readable by both human and | computers. | |- [INDEX] A directory containing index files which describe | | products published so far or on this volume. | | | |- GCONTENT.LBL A PDS label describing GCONTENT.TAB. | | | |- GCONTENT.TAB A table of GxDR frames in terms of their directory | | name and extent in latitude and longitude. | | | |- GCUMDIR.TAB The contents of all previous GxDR products | | published so far, including the GxDR on this | | volume. | | | |- GCUMDIR.LBL A PDS label describing GCUMDIR.TAB. | | | |- GEO.TAB A table of IAU-defined Venus geologic features. | | | |- GEO.LBL A PDS label describing GEO.TAB. | | |- [LABEL] A directory containing catalog information | | describing the GxDR magellan data products that | | will be submitted to PDS. The information is in | | the form of catalog templates that will be | | submitted to PDS for loading into the PDS central | | node catalog. | | | |- CATALOG.LBL PDS high-level experiment-description templates. | | | |- DSMAP.LBL PDS high-level data set templates describing | | cartographic projections and references to them. | | | |- GEDRDS.LBL PDS high-level dataset templates for GEDRs. | | | |- GREDRDS.LBL PDS high-level dataset templates for GREDRs. | | | |- GSDRDS.LBL PDS high-level dataset templates for GSDRs. | | | |- GTDRDS.LBL PDS high-level dataset templates for GTDRs. | |- [DOCUMENT] On production discs, this directory will contain | | document files (extension name "TXT") describing | | products, missions, organization, etc. | | | |- GXDR.TXT A machine-readable version of the MIT-MGN-GxDR | SIS document describing the format and contents | of the original data files supplied from MIT to | the Magellan project on magnetic tape. | |- [SOFTWARE] This directory contains useful software for | | displaying the images on this and other Magellan | | image disks. | | | |- [PC] This directory contains software for MS-DOS | | | | | |- IMDISP.EXE An executable MS-DOS binary command file for | | | enhancing and displaying images on an IBM-PC | | | computer (or compatible) with color display. | | | | | |- IMDISP.TXT An ASCII file describing the MS-DOS IMDISP command. | | | | | |- SOFTWARE.TXT A short description of the IMDISP program. | | | |- [MAC] This directory contains software for MAC-OS | | | | | |- IMAGE.HQX A compressed Apple Macintosh archive file that | | | contains the IMAGE application and its | | | documentation. Use the public-domain "BINHEX" and | | | "Stuffit" Macintosh program to unpack the archive. | | | | | |- SOFTWARE.TXT A short description of the IMAGE program. | | | |- [UNIX] | | | | | |- SOFTWARE.TXT A short description of the XMGNDISP program. | | | | | |- XMGNDISP.C C-language source code for the xmgndisp application, | | | a UNIX command that displays Magellan images in | | | version 11 of the X window system. It uses only the | | | standard Xlib routines and has been tested in the | | | following environments: | | | Hardware: MicroVAX, DecStation, Sun-SPARC | | | OS: Ultrix 4.1, SunOS 4.0.3, SunOS 4.1.1 | | | GUI: X11R3, X11R4, OSF/Motif, OpenWindows 2 | | | Window managers: olwm, mwm, twm | | | | | |- XMGNDISP.MAN UNIX manual file that documents MGNDISP. | | | | | |- XMGNDISP.TXT ASCII version of XMGNDISP.MAN. | |- [xxxxx] Four sub-directories corresponding to the four | | GxDR data types: | | | | xxxxx = GEDR (global emissivity data record) | | xxxxx = GREDR (global reflectivity data record) | | xxxxx = GSDR (global slope data record) | | xxxxx = GTDR (global topographic data record) | | | |- [yyy] four sub-directories (5 for GTDR) containing data | | | in various map projections: | | | | | | yyy = MERC Mercator projection | | | yyy = NORTH North Polar Stereographic projection | | | yyy = SINUS Sinusoidal projection | | | yyy = SOUTH South Polar Stereographic projection | | | yyy = ERROR Radius error data in sinusoidal | | | projection (for GTDR only). | | | | | |- BROWSE.IMG A 1/8 scaled (for SINUS, MERC, and ERROR) or | | | a 1/2 scaled (for NORTH and SOUTH) | | | version of the original image. | | | | | |- BROWSE.LBL A PDS label describing BROWSE.IMG. | | | | | |- PALETTE.LBL A PDS label describing PALETTE.LBL. | | | | | |- PALETTE.TAB A table of RGB color values to assist in viewing | | | or printing the image in BROWSE.IMG. For 'BYTE' | | | data (i.e. GREDR, and GSDR, and the radius error | | | GTDR image, this table will also be appropriate | | | for the image framelets themselves.) | | | | | |- FRAME.LBL A PDS label describing FRAME.TAB. | | | | | |- FRAME.TAB A table describing the range of latitude and | | | longitude within each image framelet. | | | | | |- Fff.IMG A 1024x1024-pixel image framelet file, where | | | ff is the framelet number. | | | | | |- Fff.LBL PDS labels describing the corresponding Fff.IMG. | | | | | |- HIST.LBL A PDS label describing HIST.TAB. | | | | | |- HIST.TAB A binary histogram of pixel values in the complete | | | image frame. 5. Recommended CD-ROM Drives and Driver Software VAX/VMS Drive: Digital Equipment Corporation (DEC) RRD40 or RRD50 Driver: DEC VFS CD-ROM driver V4.7 or V5.2 and up. Note: The driver software may be obtained from Jason Hyon at JPL. It is necessary to use this driver to access the XARs on the CD-ROM. VAX/Ultrix Drive: DEC RRD40 or RRD50 Driver: Supplied with Ultrix 3.1 Note: Internet users can obtain a copy of the "cdio" software package via anonymous ftp from the "space.mit.edu" server in the file named "src/cdio.shar". Contact Peter Ford for details (see below). IBM PC Drive: Toshiba, Hitachi, Sony, or compatible. Driver: Microsoft MSCDEX version 2.2. Note: The latest version of MSCDEX (released in February 1990) is generally available. Contact Jason Hyon for assistance in locating a copy. Apple Macintosh Drive: Apple CD SC (Sony) or Toshiba Driver: Apple CD-ROM driver Note: The Toshiba drive requires a separate driver, which may be obtained from Toshiba. Sun Micro (SunOS 4.0.x and earlier) Drive: Delta Microsystems SS-660 (Sony) Driver: Delta Microsystems driver or SUN sr.o Driver Note: For questions concerning this driver, contact Denis Down at Delta Microsystems, 415-449-6881. Sun Micro (SunOS 4.0.x and later) Drive: Sun Microsystems Driver: SunOS sr.o driver Note: A patch must be made to SunOS before the Sun driver can access any CD-ROM files containing Extended Attribute Records, e.g. most of the files on this disk. A copy of this patch is available to Internet users via anonymous ftp from the "space.mit.edu" server in the file named "src/SunOS.4.x.CD-ROM.patch". 6. Whom to Contact for Information For questions about how to read the CD-ROM: Jason J. Hyon MS 525-3610 Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109 818-306-6054 Electronic mail addresses: Internet: jjh345@mipl3.jpl.nasa.gov NASAmail: JHYON SPAN: MIPL3::JJH345 X.400: (ID:JHYON,PRMD:NASAMAIL,ADMD:TELEMAIL,C:USA) For questions concerning the MIT products and documentation: Peter G. Ford Center for Space Research Building 37-601 Massachusetts Institute of Technology Cambridge, MA 02139 617-253-6485 Electronic mail addresses: Internet: pgf@space.mit.edu NASAmail: PFORD SPAN: JPLPDS::PFORD X.400: (ID:PFORD,PRMD:NASAMAIL,ADMD:TELEMAIL,C:USA) 7. Cognizant Persons Mike Martin (JPL), Gail Woodward (JPL), Peter Ford (MIT), Robert Mehlman (UCLA), and Jason Hyon (JPL) designed the PDS labels and the tables. Florence Moss (JPL) and Jason Hyon developed the software to generate the PDS labels and tables. Raymond Arvidson and Gail Woodward created the catalog templates, with help from Pam Woncik (JPL), Mary Dale-Bannister (Washington University), and Susan Slavney (Washington University). The data and documentation were generated at MIT by Peter Ford, Gordon Pettengill, Fang Liu, and Joan Quigley from data supplied by the Magellan Project. Judy Mankin and Bob Canada at DADC designed the cover of this CD-ROM. This disk was produced by Jason Hyon.