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Concept

This section is a bit of a hodgepodge right now but it attempts to provide some insight into the concept of the Label Template Design Tool (LTDTool) and how it is intended to be utilzed. Although there are a couple of Node-specific tools that generate labels from templates, there is not a generic tool that can be used by all of the Nodes. The intent of this tool is to generate a template that could work in those tools and be generic enough to work in other environments. Some representative templates have been provided with the tool, but it is up to the user to create and design their template and to determine which elements should have substitution variables and which should have static values. Substitution variables can be represented as follows:

PRODUCT_ID                  = "${PRODUCT_ID}"

START_TIME                  = ${START_TIME}
      

In the example above the PRODUCT_ID element variable is quoted whether the resulting value requires quotation or not. For the START_TIME element, the variable is not quoted because date/tim e values may not be quoted according to the PDS standards. This goes for numeric values as well assuming the data type of the element has not been defined as a character string.

Inputs/Outputs

The following diagram details the inputs and outputs for LTDTool:

The inputs and outputs for the tool are described below.

Inputs

Although the tool will let the user read in just about any file to initiate a design session, the suggested inputs include PDS data products labels or previously created label templates. The current release does not perform any sort of file recognition, so it is up to the user to provide appropriate inputs. The user may also copy content from another application and paste it into the Template Editor pane as a form of input.

The tool also allows the user to import multiple PDS compliant data dictionaries. The assumption is that the user will load one instance of the Planetary Science Data Dictionary (PSDD) and any number of local data dictionaries appropriate for the design session. In this case, the tool will validate the contents of the data dictionary files. If an error occurs parsing the data dictionary file, the user will be notified. The Data Dictionary Listing pane will display the combined list of objects, elements or both (depending on the tab selected) for all of the data dictionaries imported.

The imported data dictionaries serve two purposes. The first is to provide a reference for adding objects and elements to the template in the current design session. The second is to be passed as an input to the validation function. This enables the validation function to compare the objects and elements found in the template against definitions contained in the imported data dictionaries.

Outputs

Alt hough not meant for public consumption, the tool stores the following files in the project directory (when a project is saved):

  • Working Label Template

    This file contains the saved contents of the Template Editor pane.

  • Working Data Dictionary

    This file contains any object or elements definitions that have been added or modified during the current design session.

  • Tool Preferences

    This files contains any preferences specified by the user during the current design session (i.e., file specifications for the imported data dictionaries).

The main product of this tool is the label template itself. The tool allows the user to export the label template, for the current design session, to a file and directory specified by the user. For the current release, the working label template in the project directory is essentially the same file that is exported via the Export Template function. This may not be the case in future releases.

A secondary product of this tool is the working data dictionary. The tool allows the user to export the working data dictionary, for the current design session, to a file and directory specified by the user. For the current release, the working data dictionary in the project directory is essentially the same file that is exported via the Export WDD function. This may not be the case in future releases. The purpose of the WDD is described in the Working Data Dictionary section.

The tool stores one more file that is not detailed in the diagram above. This file is a properties file named .ltdt and is stored in the user's home directory. This file contains the names of the projects and their directory loations.

Working Data Dictionary

The intent of the Working Data Dictionary (WDD) is to enable the user to augment either the Planetary Science Data Dictionary (PSDD) or a Local Data Dictionary (LDD) to accomodate a label template that is being designed for a new data product. Designers of label templates are encouraged to utilize the object and elements defined in the PSDD or any LDDs, but it is expected for example that new elements or at least new values for a defined element may be necessary when designing a new label template. Users should be aware that any new or modified definitions captured in the WDD during a design session will need to be submitted to and approved by the PDS Standards body. Hence the need for the function to export a WDD to a file. The subsections below detail the data dictionary related changes that are allowed to be captured in the WDD.

New Object or Element

New object or element definitions intended for the PSDD or an LDD may be created and stored in the WDD. A minimal definition would be required for each object or element:

  • Object Related Attributes:
    • Object Name

      The name of the object must be less than 61 characters in length consisting of < namespace > : < name > . Both the namespace and name components must contain all capital letters, numbers or underscores. Objects defined in the PSDD have an implied namespace of PSDD .

    • Object Type

      The valid values are SPECIFIC and GENERIC .

    • Required and optional sub-objects

      Any required or optional sub-objects must be defined in one of the imported data dictionaries in order for validation to work properly.

    • Required and optiona l elements

      Any required or optional sub-objects must be defined in one of the imported data dictionaries in order for validation to work properly.

    • Description

      A description of the object in free-form text.

  • Element Related Attributes:
    • Element Name

      The name of the element must be less than 61 characters in length consisting of < namespace > : < name > . Both the namespace and name components must contain all capital letters, numbers or underscores. Elements defined in the PSDD have an implied namespace of PSDD .

    • Standard Value Type

      The valid values are DYNAMIC , NONE , RANGE , STATIC and SUGGESTED .

    • Standard Value Set

      A comma separated list of values corresponding to the defined general data type.

    • Minimum / Maximum

      The minimum and maximum values for number-based general data types.

    • Minimum Length / Maximum Length

      The minimum and maximum lengths for character-based general data types.

    • General Data Type

      The valid values are CHARACTER , CONTEXTDEPENDENT , DATE , IDENTIFIER , INTEGER , NONDECIMAL and REAL .

    • Unit ID

      The unit designation (e.g., KM, DEG, NONE, etc.).

    • Description

      A description of the element in free-form text.

New objects are assumed to be specific objects instead of generic objects. For more information on object and element definitions and data dictionaries in general see the Planetary Science Data Dictionary Document .

Modified Object or Element

Modified object or element definitions intended for the PSDD or an LDD may be updated and stored in the WDD. The following modifications are allowed:

  • New optional sub-object for an object
  • New optional element for an object
  • An optional element designated as a required element for an object
  • New value or extended value range for an element

Once an object or element modification has been saved to the WDD, that object or element will appear in the Data Dictionary Listing pane twice. One entry will be the original definition and the other will be the modified definition. They can be identified by the source specified in the Definition Details pane. When the validation function is performed on the label template, the definition in the WDD will override the original definition.

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Curator: Emily.S.Law

NASA Official: William Knopf

Last Updated: 24 March 2008

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