KevinThiele - Fri Sep 15 2006 - Version 1.19
Parent topic: SddContents
SDD Part 0 is a non-normative introduction to the Taxonomic Databases Working Group SDD (Structure of Descriptive Data) Standard. Its intention is to provide a background, introduction and primer to the SDD Standard, with examples. Since the SDD Standard is a work-in-progress, this document will be updated from time to time.
In September 1998 the Taxonomic Databases Working Group (TDWG) of the International Union of Biological Sciences (IUBS) established the Structure of Descriptive Data (SDD) subgroup. TDWG’s role is to facilitate and manage the development of international standards in the taxonomic domain. The SDD subgroup was established to develop an international XML-based standard for capturing and managing descriptive data for organisms.
Development of the SDD standard was initiated in response to recognition that the existing standard previously endorsed by TDWG – the DELTA data standard developed at CSIRO in Canberra from 1971 and adopted by TDWG as a descriptive data standard in 1991 – had become inadequate (FAQ: Why not continue to use DELTA?).
The SDD subgroup began discussing and scoping a standard through an email discussion group in November 1999 (see the SDD email list archives). Considerable progress has been made at face-to-face meetings amongst a small group of core contributors, in Nov. 2001 (Canberra), Oct. 2002 (Sao Paulo), Feb. 2003 (Paris), October 2003 (Lisbon), May 2004 (Berlin) and Oct. 2004 (Christchurch).
In taxonomy, descriptive data takes a number of very different forms.
Natural-language descriptions (Box 1.2.1) are semi-structured, semi-formalised descriptions of a taxon (or occasionally of an individual specimen). They may be simple, short and written in plain language (if used for a popular field guide), or long, highly formal and using specialised terminology when used in a taxonomic monograph or other treatment.
Red Knot (Calidris canutus)
from Slater, P., Slater, P. & Slater, R. (2001) The Slater Field Guide to Australian Birds (Reed New Holland: Sydney)
Dichotomous keys (Box 1.2.2) are specialised identification tools comprising fragments of descriptive data arranged in couplets forming a branching tree. Each fragment (lead) comprises a small (occasionally verbose) natural-language description.
|Key to Australian skinks in the genus Ctenotus|
|1||Dark upper lateral zone with one or more distinct series of pale spots or blotches along the body||2|
|1a||Dark upper lateral zone obscurely mottled or uniform with at most a few pale spots anteriorly||3|
|2||Fewer than 25 lamellae under the fourth toe; supralabials 7-8 (usually 7); prefrontals separated||C. arcanus|
|2a||More than 25 lamellae under the fourth toe; supralabials 8-9 (usually 8); prefrontals usually in contact||C. alleni|
|3||Pale mid-lateral stripe passes over the hindlimb to continue along the tail||C. inornatus|
|3a||Pale mid-lateral stripe extends to groin, then continues along the front edge of the hindlimb||C. coggeri|
Lucid Interchange Format (LIF) file#Lucid Interchange Format File v. 2.1
Distribution by region
Subtropical and Temperate East and South
Arid & Semi-arid (Central)
climber (woody or herbaceous)
grass- or sedge-like plant
annual, biennial or ephemeral
[..Main Data (txs)..]
*SHOW: Gentianella - character list. Last revised 16 April 1997.
Raw data descriptions (Box 1.2.4) usually comprise repeated measurements of parts of individual specimens, and are the basis from which the more abstracted descriptions in natural language and coded descriptions are derived. Few taxonomists consistently record and archive their raw data in a standardised format.
|Specimen||Spore length||Spore width||Spore colour|
The goal of the SDD standard is to allow capture, transport, caching and archiving of descriptive data in all the forms shown above, using a platform- and application-independent, international standard. Such a standard is crucial to enabling lossless porting of data between existing and future software platforms including identification, data-mining and analysis tools, and federated databases.
This Primer is structured into several streams, each describing how SDD can help you with a specific task. For each stream, the Primer describes the core elements of SDD used to capture information related to the task, and provides examples extending from simple to complex.
The four main tasks (uses) of SDD are as follows:
Choose a link above to enter one of the SDD streams.
In addition to the streams, a number of SDD elements are common to all streams. Choose a link below to find out how to:
-- Main.KevinThiele - 07 Jul 2006