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First published 2003-11-24, last update: 2003-12-15.
TDWG working group: Structure of Descriptive Data (SDD)
The sections and subsections of the SDD schema are shown in a tabular display and annotations are provided pointing to relations and differences with the DELTA format. See also the overview SDD for DELTA experts.
| SDD model | Notes on related DELTA features | |||
| GenerationMetadata | (No information is available in DELTA on the version of DELTA in which the file is written, and on the program that created the file.) | |||
| ProjectDefinition | Some information about the entire descriptive project (title, date, authors) may be available in
*SHOW and *COMMENT directives. No information (including copyright statement) is required, however. The *NUMBER OF CHARACTERS, *MAXIMUM NUMBER OF STATES, and *MAXIMUM NUMBER OF ITEMS directives contain some technical project information which have no equivalent in SDD. | |||
| Terminology | (= similar to CHARS file in CSIRO DELTA) | |||
| Glossary | Provides definitions for characters, states, properties, structures, etc. A related feature of DELTA is the *CHAR NOTES directive. | |||
| CodingStatus | DELTA has 3 fixed "special symbols" or "pseudo-values": "U", "-", and "V". SDD does not support an equivalent to "V" but provides additional coding status values as well as a generic extensible mechanism to define these. | |||
| StatisticalMeasures | DELTA has 5 fixed measures: minimum, undefined lower range, undefined central value, undefined upper range, maximum. SDD adds various defined ranges and central values, variance measures, sample size as well as a generic extensible mechanism to define these. | |||
| Modifiers | DELTA uses free-form comments for probability, frequency ("rarely"), degree ("strongly", "weakly"), timing ("when mature"), location ("at the base"), etc. modifiers. DELTA comments have to be translated into a second language at every place they are used. In SDD all modifiers are centrally managed and translated. Probability, frequency, and by-misinterpretation further provide an analytical description. | |||
| Characters | The single flat character list containing states is relatively similar in SDD and DELTA. The character definition in SDD contains the information from the DELTA *CHAR TYPES, *KEY STATES (= SDD Mappings) directives. Note that in contrast to DELTA, the sequence of characters in SDD is not informative and is instead defined exclusively in concept trees. This allows different character sequences for different reporting purposes. | |||
| Concept Trees | Concept trees can express basic terminological concepts (structural hierarchy, property hierarchy, methods) not available in DELTA, as well as operational hierarchies for listing characters in a character definition report, in interactive keys, or in natural language reports. They define both a hierarchy (in DELTA compare the single level hierarchies *CHAR HEADINGS for character list report, *ITEM SUBHEADINGS for natural language reporting, *DEFINE CHARACTERS for Intkey) and a sequence. In contrast to DELTA, SDD can express multiple character sequences if desired. Furthermore, when used for natural language reporting (equivalent to the CSIRO DELTA TONAT command), the format and structure of the natural language description is defined here as well (*LINK CHAR, *NEW PARAGRAPHS AT CHARACTERS, *Replace Semicolon By Comma, etc. directives) | |||
| Entities | ||||
| Classes | Classes provide the equivalent of Item Names in DELTA. In SDD taxon names are centrally defined here and are linked to external taxonomic databases. | |||
| ClassHierarchies | DELTA does not support taxonomic hierarchies in general. It does provide a special multi-item taxon mechanism with main and variant items. | |||
| Objects | If biological specimens are studied in DELTA, it is possible to add the specimen identifier or description (Collector, date, etc.) as comments in the Item Name. | |||
| Resources | DELTA has no similar feature, but the proposal for a DELTA II system contains *NUMBERED LIST and *ALPHABETIC LIST directives with a similar aim. The DELTA II proposal provides only for DELTA-internal lists, not for linking with external data providers. | |||
| Agents | No management of authors, editors, contributors, translators and their respective contributions is available in DELTA. In SDD, this is a central repository for names of persons or organization, and is used throughout the data when attributing intellectual work. | |||
| Publications | Publications are not handled in the original DELTA (but proposal were made for DELTA II). Commonly information from published sources is handled as a free-form comment in DELTA. | |||
| MediaResources | In DELTA images are directly identified through path and filename. SDD allows external references, embedded resource data, and provides for a multilingual caption. | |||
| Descriptions | (= similar to ITEMS file in CSIRO DELTA) | |||
| NaturalLanguageDescriptions | DELTA has no option to markup existing natural language descriptions. Note that this section has little to do with the DELTA option to produce formatted natural language descriptions from coded data. | |||
| CodedDescriptions | This is directly equivalent to *ITEM DESCRIPTIONS in DELTA. | |||
| Keys | DELTA provides no data structure for dichotomous/multifurcating keys that are manually created or digitized from publications. | |||
Please send your criticism or suggestions to the SDD mailing list or to the author.
Gregor Hagedorn; Vers. 1; 24. November 2003