Finding the Data You Want

1. Search Options

  • Use OPUS to search for specific Cassini VIMS data products using a wide range of criteria including enhanced geometric metadata produced at the Rings node. The enhanced geometric metadata includes information appropriate to planet and satelllite searches as well as enhanced ring geometry.

    • Search results include data files, tables of associated metadata, and JPG previews for each observation. User selected data files can be bundled as tar.gz files for easy downloading.
  • The Access Data tab, for each volume gives the time interval covered by the volume and provides a link to the volume.

  • You can use the Volume_ID, coupled with subdirectory and file names (browse the data directories), or the INDEX.TAB files to find specific data (see below).

2. Interpreting the VOLUME_ID

The volume ID takes the form COVIMS_XXXX, where:

COVIMS is the PDS abbreviation for Cassini Orbiter, Visual and Infrared Mapping Spectrometer

XXXX = sequential numbering of volumes starting with 0001

3. The Volume index Files

Each volume has an index subdirectory containing these files:

  • indxinfo.txt: summarizes the structure and contents of the files in the INDEX subdirectory.

Users are encouraged to read an indxinfo.txt before working with the files in the index subdirectory.

  • index.tab: an ASCII table file with one row for each data file on the volume. For Cassini UVIS, each index table approximately 45 columns. This example is from disk COUVIS_0001. (Warning: 4.3 Mbytes!)

  • index.lbl: the detached PDS label file for the INDEX.TAB file. This is a text file giving names and definitions of all the columns in the index.

  • CUMINDEX.TAB: a cumulative version of INDEX.TAB, encompassing all prior volumes.

  • CUMINDEX.LBL: a detached PDS label for the cumulative index.

4. Useful Keywords for Ring searches

Columns in the index file that may be particularly useful to ring scientists include those for:

RINGS_FLAG, TARGET_NAME, TARGET_DISTANCE, MAXIMUM_RING_RADIUS, MINIMUM_RING_RADIUS, RING_CENTER_LATITUDE, RING_CENTER_LONGITUDE, RING_EMISSION_ANGLE, RING_INCIDENCE_ANGLE, and OBSERVATION_ID

The OBSERVATION_ID is a string constructed from the instrument ID, the orbit number, the target code, a description of the observation, and instance number. For example, VIMS_000RI_RINGMOS103_PRIME is some of the data taken by VIMS during orbit 000 to produce a radial mosaic of the rings.

Searching the index file for the substring RI_ will identify general ring observations. Observations devoted to a specific ring (A through G) may be indicated by RA_, RB_, RC, RD_, RE_, RF_, and RG_ respectively