Global Attributes
The Global Attributes panel allow the user to view and edit the ISTP/SPDF
defined global attributes of the file. Global attributes are used
to provide information about the data set as an entity. Together with variables
and variable attributes, the global attributes make the data correctly
and independently usable by someone not connected with the instrument team,
and hence, a good archive product. Global attributes are catagorized
as those which are required for ISTP guideline compliance and those that
are merely recommended. The definition of each global attribute is
contained in the ISTP/SPDF Guidelines
(see https://spdf.gsfc.nasa.gov/istp_guide/gattributes.html).
Required Attributes
Project
This attribute identifies the name of the project and indicates ownership.
For ISTP missions and investigations, the value used is "ISTP>International
Solar-Terrestrial Physics". For the Cluster mission, the value is "STSP
Cluster>Solar Terrestrial Science Programmes, Cluster". Other acceptable
values are "IACG>Inter-Agency Consultative Group", "CDAWxx>Coordinated
Data Analysis Workshop xx", "SPDS>Space Physics Data System", and "NSSDC>National
Space Science Data Center Archived Data". Others may be defined in future.
This attribute can be multi-valued if the data has been supplied to more
than one project.
Source Name
This attribute identifies the mission or investigation that contains the
sensors. For ISTP, this is the mission name for spacecraft missions or
the investigation name for ground-based or theory investigations. Both
a long name and a short name are provided. This attribute should be single
valued.
Descriptor
This attribute identifies the name of the instrument or sensor that collected
the data. Both a long name and a short name are given. An example for ISTP
is "EPI>Energetic Particles and Ion Composition". The short name should
be limited to from 2 to 4 characters for consistency with ISTP. This attribute
should be single valued.
Data Type
This attribute identifies the data type of the CDF data set. Both a long
name and a short name are given. For ISTP exchangeable data products the
values are "Kn>Key Parameter" for approximately minute averaged survey
data, and "Hn>High Resolution data" for certified data of higher resolution
than Key Parameters.$n$ can run from 0 to 9 to allow for more than one
kind of data product. For Cluster/CSDS this can either be "SP>Summary Parameter"
or "PP>Prime Parameter". Other possible data types may be defined in future.
If any of these data sets are modified or used to produce derived products,
the data type should be, e.g., "Mn>Modified Data n", where n is from 0
to 9.
File Naming Convention
This attribute value describes the file naming convention that is used in
naming CDF files. The user may select from a number of different conventions
involving the source, datatype, descriptior, and date/time values.
PI Name
This attribute value should include first initial and last name.
PI Affiliation
This attribute value should include a recognizable abbreviation.
Discipline
This attribute describes both the science discipline and subdiscipline.
More than one entry is allowed.
Mission Group
This attribute has a single value and is used to facilitate making choices
of source through CDAWeb (https://cdaweb.gsfc.nasa.gov/).
Data Version
This attribute identifies the version of a particular CDF data file for
a given date, e.g., the file
GE_K0_MGF_19920923_V01 is the first version of data for 1992 September
23. Each time this particular data file is reproduced - for recalibration
or other reasons - the Data_version is incremented by 1. Data_version always
starts at `1'.
Instrument Types
This attribute is used to facilitate making choices of instrument type
through CDAWeb. More than one entry is allowed.
Logical Source Description
This attribute contains a more readable description of the cryptic
Logical_source
attribute.
Descriptive Text
This attribute is an NSSDC standard global attribute which is a text description
of the experiment whose data is included in the CDF. A reference to a journal
article(s) or to a World Wide Web page describing the experiment is essential,
and constitutes the minimum requirement. A written description of the data
set is also desirable. This attribute can have as many entries as necessary
to contain the desired information.
Recommended Attributes
Acknowledgement
Text string at PI disposal allowing for information on expected acknowledgment
if data is citable.
Rules of Use
Text containing information on, {\it e.g.} citability and PI access restrictions.
This may point to a World Wide Web page specifying the rules of use.
SPASE ID
Unique dataset identifier assigned by http://www.spase-group.org/, of the
form spase://VSPO/"UNIQUE_ID", where "UNIQUE_ID" is the ID assigned to
the SPASE resource record for the dataset in the SPASE system. The SPASE
resource record provides metadata about the dataset, including pointers
to locations holding the data.
Time Resolution
Specifies time resolution of the file, e.g., "3 seconds".
Generated by
This attribute allows for the generating data center/group to be identified.
Generation Date
Date stamps the creation of the file using the syntax yyyymmdd, e.g., "19920923".
This is distinct from the date in "validate" below which records the times
of later validation processes.
Link Text
This attribute stores text describing on-line data available at PI or CoI
web sites. This attribute is used in conjunction with "LINK_TITLE" and
"HTTP_LINK". There can be up to 5 entries for each - there MUST be a corresponding
entry of "LINK_TITLE" and "HTTP_LINK" for each "LINK_TEXT" entry. CDAWeb
will then link to the URL given by "HTTP_LINK" using the "LINK_TITLE" and
the description in "LINK_TEXT", on the CDAWeb Data Explorer page.
For example
"LINK_TEXT" = 3-sec MGF magnetic field 1 Sep
1993 through 30 Sep 1997 available at
"LINK_TITLE" = ISAS DARTS
"HTTP_LINK" = http://www.darts.isas.ac.jp/spdb/index.html
will give the following link:
3-sec MGF magnetic field 1 Sep 1993 through 30 Sep 1997 available at
ISAS
DARTS
Link Title
This attribute stores the title of the web site holding on-line data available
at PI or CoI web sites. This attribute is used in conjunction with "LINK_TEXT"
and "HTTP_LINK". There can be up to 5 entries for each - there MUST be
a corresponding entry of "LINK_TEXT" and "HTTP_LINK" for each "LINK_TITLE"
entry. CDAWeb will then link to the URL given by "HTTP_LINK" using the
"LINK_TITLE" and the description in "LINK_TEXT", on the CDAWeb Data Explorer
page.
HTTP Link
This attribute stores the URL for the PI or CoI web site holding on-line
data. This attribute is used in conjunction with "LINK_TEXT" and "LINK_TITLE".
There can be up to 5 entries for each - there MUST be a corresponding entry
of "LINK_TEXT" and "LINK_TITLE" for each "HTTP_LINK" entry. CDAWeb will
then link to the URL given by "HTTP_LINK" using the "LINK_TITLE" and the
description in "LINK_TEXT", on the CDAWeb Data Explorer page.
ModificationHistory
This attribute is an NSSDC standard global attribute which is used to denote
the history of modifications made to the CDF data set. The attribute should
contain a description of all significant changes to the data set. This
attribute is not directly tied to Data_version, but each version produced
will contain the relevant modifications. This attribute can have as many
entries as necessary to contain the desired information.
See also:
-
Space Physics Guidelines for CDF
(see https://spdf.gsfc.nasa.gov/sp_use_of_cdf.html).
-
CDA Web (https://cdaweb.gsfc.nasa.gov/).