Global Attributes

The Global Attributes panel allow the user to view and edit the ISTP/IACG 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/IACG Guidelines (http://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.

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.

ADID Ref

This attribute stores the control authority identifier associated with the detached SFDU label. If no control authority identifier has been assigned, then the identifier associated with the ISTP/IACG Guidelines (NSSD0241) or with CDF (NSSD0110) can be used.

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: