PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2013-05-06 INTERCHANGE_FORMAT = ASCII NOTE = "Introduction to CHEMCAM EDR Data" END_OBJECT = TEXT END Mars Science Laboratory (MSL) ChemCam EDR Data Archive 1. Introduction This archive contains data acquired by the Mars Science Laboratory (MSL) ChemCam instrument. Specifically, this archive includes version 1 of the EDR, CODMAC Level 2, data products. Also in this volume there is documentation of the data format used along with the calibration plan, where much information about the instrument can be found. 2. File Formats This section describes the format of MSL EDR Archive Volumes. Data that comprise the Archive will be formatted in accordance with Planetary Data System standards. 2.1. File Formats This section describes file formats for the kinds of files contained on Archive Volumes. 2.1.1. Document File Formats Document files with the .TXT suffix exist in the ROOT, DATA, INDEX, CATALOG, DOCUMENT, LABEL, CALIB and EXTRAS directories. They are ASCII files which may have embedded PDS labels. Lines in a .TXT file end with a carriage return character (ASCII 13) and a line feed character (ASCII 10). This allows the files to be readable under various operating systems. Some documents in the DOCUMENT contain formatting and figures that cannot easily be rendered as ASCII text. Therefore each document is given in PDF 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. Some type of ASCII text versions of these documents will also be included, possibly using HTML or XML, in order to meet the PDS requirement that documents must be archived as ASCII text. 2.1.2. Tabular File Format Tabular files (.TAB or .CSV suffix) exist in the INDEX and CALIB directory. Tabular files are ASCII files formatted for direct reading into many database management systems on various computers. Every MSL tabular file is described by a detached PDS label with the same name as the data file it describes, and the extension .LBL. For example, the file INDEX.TAB is accompanied by the detached label file INDEX.LBL in the same directory. 2.1.2.1 INDEX Directory All fields for tabular files in the INDEX directory are separated by commas. (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" listed in the labels indicate the starting position in bytes of each field in a record; the field length "bytes" does not include the commas between 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 text file with embedded line delimiters on those that do not. 2.1.2.2 CALIB Directory CALIB data files are stored as ASCII tables with file names ending in CSV. The tables are in comma-separated-value format, meaning that fields in a row are separated by commas, and the fields are not padded with spaces to be the same length in each row. Hence the lengths of rows in a table may vary. Each table is accompanied by a detached PDS label with the same name but the extension LBL, which describes the format and content of the table. PDS labels are ASCII text files that may be read in a text editor. The last two bytes of each record contain the ASCII carriage return and line feed characters. 2.1.3. PDS Label Format All data files in the MSL EDR archive have PDS labels detached in a separate file. For examples of PDS labels for each type of data product, see the Data Product SIS in the DOCUMENT directory. A PDS label provides descriptive information about the associated file. The PDS label is an object-oriented structure consisting of sets of 'keyword=value' declarations. 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 where to find the object. 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 in the file. For example: ^HEADER = ("F01.IMG",1) ^IMAGE = ("F01.IMG",1025 ) indicates that the IMAGE object begins at byte 1025 of the file F01.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 = ("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 up to 28 character, alphanumeric upper-case file name, ext is the 3 character upper-case file extension Lines of text in detached labels end with a carriage return character (ASCII 13) and a line feed character (ASCII 10). This allows the files to be readable under various operating systems. Note that the RECORD_TYPE keyword located in the first five lines of the PDS label has the value UNDEFINED because the label points to multiple data types. 2.1.4. Catalog File Format Catalog files (suffix .CAT) exist in the ROOT and CATALOG directories. They are text files formatted in an object-oriented structure consisting of sets of 'keyword=value' declarations, so that they are readable by humans and by software. All lines terminated with carriage return and line feed characters. 2.1.5 EDR File Format ChemCam EDR data files are stored as binary tables with file names ending in DAT. Each one is accompanied by a detached PDS label with the same name but the extension LBL, which describes the format and content of the binary table. PDS labels are text files. The label file may include a pointer to a format file, with a name ending in FMT. (For example, such a pointer might be ^STRUCTURE = "CCAM_LIBS_ANCILLARY_V4.FMT".) Format files are fragments of labels that are intended to be read by software as if they were inserted into the label where the pointer statement is located. They describe details of the binary table's column structure. Format files are located in the LABEL directory. In this way long column definitions are stored in only one place and do not have to be repeated in every data product's label. For more information about the format and content of the data products, see the discussions in the MSL Data Product and Archive Volume SISs located in the DOCUMENT directory. MSL EDR Data Products are viewable with NASAView, the PDS' standard viewing tool. 3. Archive Contents Files in this archive are organized into a series of subdirectories below the top-level directory. The archive organization and the contents of each directory are described below. Top-level Directory ------------------- AAREADME.TXT The file you are currently reading. ERRATA.TXT This text file contains a listing of comments and updates concerning the archive volume. VOLDESC.CAT This text file contains a description of the volume contents as a PDS catalog object. It is a required file on PDS archive volumes. DATA Directory -------------- The DATA directory contains MSL ChemCam (EDR) data products. See MSL_CAMERA_SIS.PDF and MSL_EDR_VOLSIS.PDF for details. INDEX Directory --------------- The INDEX directory contains PDS index files for this archive. An index file is an ASCII table with each record (or line) in the table containing information about a single data product in archive. Files in the Index directory are provided to help the user locate products on the archive volume. See the file INDXINFO.TXT for additional details. DOCUMENT Directory ------------------ The DOCUMENT directory contains contains documentation to help the user understand and use the archive data. See DOCINFO.TXT for a description of the files in the DOCUMENT directory. CATALOG Directory ----------------- The files in the Catalog directory provide a top-level understanding of the mission, spacecraft, instruments, and data set. The files in this directory become part of the PDS Catalog to provide background information for the user searching for data. Their format and contents are further specified in the PDS Standards Reference. See the file CATINFO.TXT for details. CALIB Directory ------------------ The CALIB directory contains calibration data from LIBS data from various environments. EXTRAS Directory --------------- The EXTRAS directory contains other materials that the user may find helpful, but that are beyond the scope of the required elements of the archive. 4. Whom to Contact for Information For questions concerning this volume set, contact: OPGS Representative: Rafael Alanis, Jet Propulsion Laboratory, Rafael.Alanis@jpl.nasa.gov ChemCam Science Team Archive Representative: Dorothea DeLapp, Los Alamos National Labortory, ddelapp@lanl.gov or Olivier Gasnault, INSTITUT DE RECHERCHE EN ASTROPHYSIQUE ET PLANETOLOGIE (IRAP), olivier.gasnault@irap.omp.eu PDS Geosciences Node Representative: Susan Slavney, Washington University, Susan.Slavney@wustl.edu. For general information related to the PDS, contact: Planetary Data System, PDS Operator M/S 202-101 Jet Propulsion Laboratory 4800 Oak Grove Drive Pasadena, CA 91109-8099 (818) 354-4321 WWW Site: http://pds.jpl.nasa.gov/ E-mail: pds_operator@jpl.nasa.gov