This page describes how the RPW CDF files are generated by the ROC pipelines, and what are the tools required
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RPW CDF Data Standards
RPW/SOLAR ORBITER CDF DATA
The SOL-SGS-TN-0009 document from ESA gives the convention to be applied by the in situ instrument teams concerning the CDF data products. This document can be found in https://issues.cosmos.esa.int/solarorbiterwiki/display/SOSP/SOC+Documents.
RPW/ROC-SGSE CDF DATA
The conventions concerning the RPW data - format, metadata, file naming convention, versioning, etc. - produced on-ground by the ROC-SGSE can be found in the "Data format and metadata definition for the ROC-SGSE" document.
RPW CDF file creation mechanism
Every RPW CDF data files must be produced using the CDF skeleton mechanism (for more information about CDF and skeletons, visit https://cdf.gsfc.nasa.gov/).
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- The name of the skeleton file for each data set is reported in the "Data Definition Schema File" column in the ROC-SGSE and RPW data products lists.
Building CDF file name for science data
The file naming convention for the RPW CDF data files is defined in [RD1].
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RPW CDF skeleton file storing
RPW skeleton files archive is stored in the ROC DataPool Git repository: https://gitlab.obspm.fr/ROC/DataPool/tree/master/ROADS/RODP/CDF
ROC CDF Skeleton Conversion Tools
Conversion of a CDF skeleton files between ASCII, binary and Excel formats
The "maser4py" python package can be used to convert a given CDF skeleton file between the ASCII, binary and Excel formats,
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Conversion of a CDF skeleton table to the master CDF binary file
The main way to convert a CDF skeleton table to a master CDF binary file is to use the "skeletoncdf" tool of the NASA CDF standard library (https://cdf.gsfc.nasa.gov/).
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The master CDF binary file can also be generated from the skeleton table using the skeletoncdf module of the maser4py package. |
Some rules to keep in mind when editing a CDF skeleton file
About CDF variables
- All of the CDF variables shall be zVariables
- The first variable on the CDF file shall always be "Epoch" (becareful that the variable naming is case sensitive).
- Except "Epoch", all of the variables shall be named using capital letters only, shall start with a letter and shall contain alphanumeric plus underscore and hyphens characters only
- Variables of "Data" type shall be real or integer only: CDF_UINT1, CDF_UINT2, CDF_UINT4, CDF_INT1, CDF_INT2, CDF_INT4, CDF_REAL4, and CDF_REAL8.
- The variables shall always be non-fixed "Record variance" (i.e., "T")
- The "Number Elements" parameter of a given variable is always "1", except for CDF_[U]CHAR data type, where it gives the (maximal) number of characters in the string.
- A scalar variable shall always has a 0 dimension (i.e., "Dims = 0)
About variable attributes
- The "DEPEND_0" variable attribute value shall always be "Epoch".
- Depending of variable data type, the FILLVAL attribute value shall comply the ISTP guidelines (see http://spdf.gsfc.nasa.gov/istp_guide/vattributes.html#FILLVAL)
- The CDF data type of the following attributes shall match the corresponding zVariable data type: "VALIDMIN", "VALIDMAX", "SCALEMIN", "SCALEMAX", "FILLVAL".
- Make sure to always give a default value for the following attributes: "VALIDMIN", "VALIDMAX", "SCALEMIN", "SCALEMAX", "FILLVAL". If you do not know which values to give to ["VALIDMIN", "VALIDMAX"] you should use the maximal data type encoding values, but not the FILLVAL value (e.g. for a "CDF_UINT1" data type, [0, 254]). Same, if you do not know which default values for the ["SCALEMIN", "SCALEMAX"] set, you should use the ["VALIDMIN", "VALIDMAX"] values. For the FILLVAL, please use the ISTP guideline values as explained above.
About CDF header
- The DATA ENCODING shall always be "NETWORK"
- The MAJORITY shall always be "COLUMN"
- The FORMAT shall always be "SINGLE"
References
CDF Tools
Several language libraries are available to handle the CDF format.
Here are a non-exhaustive list:
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