wiki-archive/twiki/temp-gjr/BDI/SDD/DeltaComplexity.txt

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---++Complexity of DELTA

---+++Introduction

The proposed BDI.SDD_ schema has significant complexity and we believe that the complexity is necessary to store high quality data. However, we have taken great care to allow relatively simple BDI.SDD_ documents to be created. The [[PrimerHome][BDI.SDD_ primer]] explains the basics of using BDI.SDD_. 

A frequent argument we encounter is that BDI.SDD_ is more complex and difficult than DELTA. For a number of reasons we do not think this is true. One problem when comparing the complexity of <a href="http://biodiversity.bio.uno.edu/delta/">DELTA</a> and BDI.SDD_ is that the complexity of DELTA itself is difficult to assess. DELTA has a few basic directives, namely Character Type, Character List, and Item Descriptions that are minimally sufficient to start describing items. Character List, and Item Descriptions are, however, highly structured and map to several BDI.SDD_ elements.

To allow some degree of comparison I have prepared a list of DELTA directives based on the information in the latest version of the "User's Guide to the DELTA System" (Edition 4.12 by M.&nbsp;J. Dallwitz, T.&nbsp;A. Paine, and E.&nbsp;J. Zurcher, 2000). Since DELTA is originally a command-driven language, some directives contain data, whereas other directives give commands to execute methods in a specific program. The distinction is, however, weak. Many reporting directives (!*Omit Inner Comments, !*Omit Lower For Characters) are required when creating natural language descriptions or keys, and some commands (e.&nbsp;g. or *Insert Implicit Values) have to be executed to obtain meaningful data. Still other "commands" like !*Input File provide the basic functionality to find the files belonging to a project. No other program will be able to create natural language descriptions or keys without evaluating these "command"-like directives.

---+++Overview of DELTA directives

In the list below I have attempted to mark all [[DeltaDirectives][directives]] that are informative only in the context of using the CSIRO DELTA programs in gray and those that contain valuable descriptive or terminological definitions in bold face. Directives considered obsolete or deprecated by DELTA (e.&nbsp;g. !*State Codes) are marked gray as well.

<p class="small"><b>*Absolute Error</b>, <span style="color:gray">*Accept Duplicate Values</span>, <b>*Add Characters</b><!--(Note: = item specific Include Characters directive, not supported by BDI.SDD_!)-->, <b>*Alternate Comma</b>, <b>*Applicable Characters</b>, <b>*Character For Output Files</b>, <b>*Character Descriptions<!-- syn. of Char List, used by Pankey --></b>, <b>*Characters For Synonymy</b>, <b>*Character For Taxon Images</b>, <b>*Character For Taxon Names</b>, <b>*Character Headings</b>, <b>*Character Images</b>, <b>*Character Keyword Images</b>, <b>*Character List</b>, <b>*Character Notes</b>, <b>*Character Reliabilities</b>, <b>*Character Types</b>, <b>*Character Weights</b>, <b>*Chinese Format</b>, <b>*Comment</b>, <span style="color:gray">*Data Buffer Size</span>, <span style="color:gray">*Data Compression</span>, <span style="color:gray">*Data Listing</span>, <b>*Decimal Places</b>, <b>*Dependent Characters</b>, <span style="color:gray">*Disable Delta Output</span>, <span style="color:gray">*Dist Output File</span>, <b>*Emphasize Characters</b>, <b>*Emphasize Features</b>, <span style="color:gray">*End</span>, <span style="color:gray">*Error File</span>, <b>*Exclude Characters</b>, <b>*Exclude Items</b>, <b>*Heading</b>, <b>*Image Directory</b>, <b>*Implicit Values</b>, <b>*Inapplicable Characters</b>, <b>*Include Characters</b>, <b>*Include Items</b>, <span style="color:gray">*Index Headings</span>, <span style="color:gray">*Index Output File</span>, <span style="color:gray">*Index Text</span>, <span style="color:gray">*Input Delta File</span>, <span style="color:gray">*Input File</span>, <span style="color:gray">*Insert Character Sequence Numbers</span>, <span style="color:gray">*Insert Image File Name</span>, *Insert Implicit Values, <span style="color:gray">*Insert Item Sequence Numbers</span>, <span style="color:gray">*Insert Redundant Variant Attributes</span><!-- convert Variant taxa into full descriptions -->, <span style="color:gray">*Intkey Output File</span>, <b>*Item Abundances</b>, <b>*Item Descriptions</b>, <b>*Item Headings</b>, <span style="color:gray">*Item Output Files</span>, <b>*Item Subheadings</b>, <b>*Item Weights</b>, <b>*Key Character List</b>, <span style="color:gray">*Key Output File</span>, <b>*Key States</b>, <b>*Link Characters</b>, <span style="color:gray">*List Characters</span>, <span style="color:gray">*List Heading</span>, <span style="color:gray">*List Items</span>, <span style="color:gray">*Listing File</span>, <b>*Mandatory Characters</b>, <span style="color:gray">*Maximum Number Of Items</span>, <span style="color:gray">*Maximum Number Of States</span>, <b>*New Files At Items</b>, <span style="color:gray">*New Listing Page</span>, <b>*New Paragraphs At Characters</b>, <span style="color:gray">*New Print Page</span>, <span style="color:gray">*No Data Listing</span>, <b>*Nonautomatic Controlling Characters</b><!-- related to character dependency -->, <span style="color:gray">*Number Of Characters</span>, <span style="color:gray">*Number States From Zero</span>, <span style="color:gray">*Numbers Of States</span>, <span style="color:gray">*Omit Character Numbers</span>, <span style="color:gray">*Omit Comments</span>, <b>*Omit Final Comma</b>, <b>*Omit Inapplicables</b>, <b>*Omit Inner Comments</b>, <b>*Omit Lower For Characters</b>, <b>*Omit Or For Characters</b>, <b>*Omit Period For Characters</b>, <span style="color:gray">*Omit Redundant Variant Attributes</span><!-- reduce descriptions of Variant taxa to include only difference to parent -->, <b>*Omit Space Before Units</b>, <span style="color:gray">*Omit Typesetting Marks</span>, <span style="color:gray">*Output Directory</span>, <span style="color:gray">*Output File</span>, <span style="color:gray">*Output Format Html</span>, <span style="color:gray">*Output Parameters</span>, <span style="color:gray">*Output Width</span>, <span style="color:gray">*Overlay Fonts</span>, <span style="color:gray">*Page Length</span>, <b>*Percent Error</b>, <span style="color:gray">*Previous Input File</span>, <span style="color:g

Note 1: The Intkey directives at the end are normally considered Intkey command line commands rather than DELTA directives. However, the three listed provide essential functionality for DELTA. Otherwise the list of Intkey commands is incomplete, ca. 70 further Intkey commands exist. <b>*Define Characters</b> is used to define character groups for interactive identification in Intkey (and is also supported by DeltaAccess).

Note 2: DELTA directives must be all-uppercase. here they have been written in normal capitalization to improve readability.

The markup above is a personal estimate and other consumers of DELTA data may want to use other directives. However, the list of directives shown in boldface shows that DELTA as a fully usable system is quite complex as well, and necessarily so if all of interactive keys, guided key generation, and natural language descriptions shall be supported.

Furthermore, a comparison between DELTA and BDI.SDD_ should consider not only the old DELTA standard, but also the considerably more complex proposal for a new DELTA (M.&nbsp;J. Dallwitz, T.&nbsp;A. Paine, and E.&nbsp;J. Zurcher (1993 onwards, <a href="http://biodiversity.uno.edu/delta/www/proposal.htm">1999</a>, <a href="http://delta-intkey.com/www/proposal.htm">2005</a>) Proposed New Features for the DELTA System). BDI.SDD_ does address most of the issues raised in the DELTA II proposal.

*See also the overview [[DELTAandBDI.SDD][DELTA and BDI.SDD_]].*

-- Main.GregorHagedorn - 10 May 2006 (First version published outside of Wiki by Gregor Hagedorn on 20. November 2003)


%META:TOPICMOVED{by="GregorHagedorn" date="1147273199" from="SDD.DELTAComplexity" to="SDD.DeltaComplexity"}%