CCSD3ZF0000100000001NJPL3IF0PDS200000001 = SFDU_LABEL RECORD_TYPE = STREAM OBJECT = TEXT NOTE = "Introduction to this CD-ROM volume." END_OBJECT END Voyagers to the Outer Planets Volume 16 - Jupiter Selected Images in Range 16024.02 - 16212.34 in Compressed Format Selected Images in Range 16024.02 - 16212.34 in Browse Format This Compact Disk Read-Only Memory (CD-ROM) volume is one of the set of volumes containing all images taken by NASA's twin Voyager spacecraft during their encounters with the planet Jupiter. The set of volumes which comprise the complete Jupiter image data set begins with volume 13 of the "Voyagers to the Outer Planets" collection and proceeds chronologically through the data set. The earlier volumes in the collection contain: a complete Uranus image data set (volumes 1-3) a set of selected Saturn images (volumes 4-5) a set of selected Jupiter images (volumes 6-8) a complete Neptune image data set (volumes 9-12) The images on volumes 6-8 (selected image data) will be repeated somewhere on the complete image data set volumes. The image data will be unchanged, but corrections may have been made to descriptive information (in the label or the Index Table) such as TARGET or NOTE. In the case of corrected TARGET values, a repeated image may show up in a different directory than it did on volumes 6-8. The images are full resolution (800 pixels by 800 scan lines) digital images returned by the Voyager cameras. No additional processing has been performed to enhance the images. The images are compressed to permit us to pack more data onto each volume, but the images can be restored to their full resolution using algorithms described in documentation on this disk. Image decompression software in several programming languages is also included on the disk. Sub-sampled "Browse" images consist of every fourth pixel of every fourth scan line, producing an image of 200 pixels by 200 scan lines. Browse images allow rapid location of images of interest, prior to retrieving and decompressing the compressed version of the image to get the full 800 pixel by 800 scan line resolution. Only a few files, including this one, are located in this volume's main directory. The file, VOLDESC.SFD, contains general information similar to what is in this file but in a format that is easier for computer programs to access. All other files are located in directories below the main directory. The directory named DOCUMENT contains a document file named VOLINFO.TXT that describes in detail the organization of this disk, as well as the format and content of the Voyager images. It is highly recommended that the VOLINFO document be read before trying to process image files. Also in the DOCUMENT directory is a file called ANOMALY.TXT which describes both missing data and known anomalies. The directory named INDEX contains a file IMGINDEX.TAB which is an index to the images on this volume. The index table is human and machine readable. While you can locate images by simply searching through the index yourself, the table has been designed so that it can be easily loaded into most database managers for fast and efficient searching. The file named INDXINFO.TXT in the INDEX directory describes the index table in detail. The directory named SOFTWARE contains source and executable versions of image decompression software written in Fortran, C and VAX Macro assembly language. There are executable decompression programs for use with Macintosh, IBM PC, UNIX and VAX/VMS systems. The file named SOFTINFO.TXT in the SOFTWARE directory briefly describes the software. More detailed information is found in the .TXT files stored with the software modules in the MAC, PC, UNIX and VAX subdirectories. The compressed image files are contained in directories named after the principal target of the image. The image directories present on this Jupiter volume are: JUPITER - Images of Jupiter AMALTHEA - Images of satellite Amalthea CALLISTO - Images of satellite Callisto EUROPA - Images of satellite Europa GANYMEDE - Images of satellite Ganymede IO - Images of satellite Io THEBE - Images of satellite Thebe CALIB - Unshuttered images in the DARK subdirectory If there are more than about 100 images of a target on a volume, the images are further divided into subdirectories based upon their image number. Each image subdirectory has a name of the form CnnnnXXX, where nnnn is the first four digits of the seven-digit image number. All images of the target with image numbers that have those first four digits will appear in the subdirectory. See the document in file VOLINFO.TXT for further information about image numbers. The Browse image files are arranged into directories using the scheme outlined above for compressed images. The only difference is that all of the Browse image directories are located under the directory named BROWSE. Within the BROWSE directory for example, is a subdirectory named GANYMEDE that contains all of the Browse format images of the satellite GANYMEDE. Most files on this disk have a label encoded in the Object Description Language (ODL). A file's ODL label is readable by both humans and computers, and it provides a formal description of the format and content of the file. For most files the ODL label appears at the beginning of the file (this is the case for the file that you are currently reading). All image files have such an embedded ODL label preceding the data in the file. For files where labels can't be easily included, a separate label file is provided that contains the ODL label and a pointer to the file that the label describes. These external label files all have a .LBL file extension. An example of an external label is the file IMGINDEX.LBL in the INDEX directory which contains the ODL label for the index file IMGINDEX.TAB. The LABEL directory contains two files with external ODL labels that describe the format and content of the engineering information that is contained within each image file. The Object Description Language is described in the document file VOLINFO.TXT in the DOCUMENT directory.