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M.J. Dallwitz, T.A. Paine, and E.J. Zurcher
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The DELTA System is an integrated set of programs based on the DELTA format. The facilities available include the generation and typesetting of descriptions and conventional keys, conversion of DELTA data for use by classification programs, and the construction of Intkey packages for interactive identification and information retrieval.



-INSTALLATION AND USAGE: offline, interactive key (intkey) can run as helper application online. 

-FORMATS: native format: text, convertible to binary - importing format: DELTA is the native format - exporting format: Nexus. Data matrix can be copied to Excel and thence to CSV.

-KNOWLEDGE REPRESENTATION: possible to represent quantitative data (up to 5 values, e.g. (3-)5-7-10(-15), representing extreme values, "normal" values, and measure of central tendency. Interpretation (e.g. percentiles for the "normal" values) could stated informally by the author. Other information recordable as comments - manage polymorphism - missing data: only by comments - manage misinterpretation in prototype form.

-MEDIA SUPPORT: possibility to add pictures of the taxa, link to any external source that can be handled by file-type associations, e.g. Web files, Word documents, possibility to add videos and sounds.

-FUNCTIONALITIES: editing, natural-language descriptions, interactive identification, coventional keys, phenic analysis. Phylogenetic analysis via export to Nexus and Hennig86 formats. Not possible to read and to edit the same knowledge base from several computer concurrently. Doesn't manage uncertainty. History of identification: history of steps. Multi-access key. Possibility to have access to a complete descriptive card of the identified taxon.

-USER INTERFACE: online help available in Intkey - languages: intkey only (English, French, German, Portuguese, Spanish) - loading time: download and install Intkey 1 minute, whole DELTA package~2 minutes - launch time: 2 seconds - dynamic community: DELTA-L mailing list. See link at - possible future developments: No.

System Requirements: 

The programs run under Windows 98, Windows NT 4.0, and later versions of these systems, without any special requirements. The programs also run under Windows 95, provided that version 2 or later of Microsoft’s ‘rich-edit’ control is available (riched20.dll in the Windows ‘system’ folder). This was not distributed with Windows 95, but will be present if you have installed MS Office 97 or later, MS Word 97 or later, or MS Word Viewer 97/2000. The latter is available free of charge at Click on ‘Downloads’, search for ‘Word Viewer’, and click on ‘Word 97/2000 Viewer’. When installed, Intkey requires about 2MB of disk space, and the full DELTA System about 8MB.

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