A “SPICE data” catalog file specifies all the SPICE kernels that need to be loaded to run a visualization for a particular mission. This is an example of a SPICE data catalog file listing CASSINI SPICE data:
{
"version": "1.0",
"name": "Cosmographia CASSINI Example",
"spiceKernels": [
"kernels/cas_1997_v15.tm",
"kernels/cas_1998_v15.tm",
"kernels/cas_1999_v15.tm",
"kernels/cas_2000_v17.tm",
"kernels/cas_2001_v18.tm",
"kernels/cas_2002_v17.tm",
"kernels/cas_2003_v17.tm",
"kernels/cas_2004_v17.tm",
"kernels/cas_2005_v18.tm",
"kernels/cas_2006_v17.tm",
"kernels/cas_2007_v15.tm",
"kernels/cas_2008_v13.tm",
"kernels/cas_2009_v10.tm",
"kernels/cas_2010_v09.tm",
"kernels/cas_2011_v08.tm",
"kernels/cas_2012_v05.tm",
"kernels/cas_2013_v02.tm"
]
}
Note that SPICE data catalogs can load SPICE meta-kernels, as shown in this example, as well as individual SPICE kernels.
The version and name attributes are set to the catalog format/content version (must be “1.0”) and the internal name of the catalog file.
The spiceKernels attribute lists the names of the SPICE kernels and/or meta-kernels to be used for the mission of interest. The total number of SPICE kernels is limited only by SPICE capabilities. Loading a large number of SPICE kernels (hundreds or thousands) lengthens loading time but normally does not affect visualization speed. Note the following:
-
Use and maintenance of this kind of catalog file tends to be easier with the use of SPICE meta-kernels rather than individual SPICE files.
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Multiple kernel/meta-kernel names in the list must be separated by commas (this follows the catalog convention for an array).
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Individual kernels and meta-kernels provided in the list must be loadable from the directory in which the catalog file resides. For meta-kernels this means that kernels included in them must use correct relative and/or absolute paths.
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When using SPICE data from the PDS’ NAIF Node archive, multiple meta-kernel versions for a mission, or for each year of a mission, may exist. In this case, use only the latest version meta-kernel for the mission or for a given year.
A more detailed description of some of the parameters in this catalog file is provided in the “CATALOG FILE SETTING UP USE OF SPICE DATA” section of the Cosmographia-SPICE User’s Guide.
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