UMASS-Boston Electronic Field Guide Project UMASS-Boston
Electronic Field Guide Project

Multimedia  Polychotomous Keys

A key author provides a representation of a polychotomous key in a data structure we call a "Property List Decorated Tree"(PLD Tree). At each node, a PLD Tree has a list of key-value pairs from which applications can produce information in a form suitable to themselves or produce queries to databases, the responses to which provide the input to the application's information production. The key can be input in XML more useful to biologists in an Excel spreadsheet which our software converts to the XML form. At interior nodes, a typical key might have key-value pairs that designate diagnostic characters (properties which allow a decision as to which tree to follow) and references to media files that illustrate the choices. At leaf nodes, a key might have a property that simply denotes a taxon name denoting the identification produced by the path to node, or (more interestingly) it might support a query into a database known to, or discoverable by, an application processing the key. In our use of such keys, these queries produce descriptive taxon pages.

You can see detailed instructions on how to create such a key.

Most of the keys in the current application are derived from several Excel keys, produced by William Haber, our collaborator in Costa Rica. To produce a key, Haber gave us several excel files corresponding to each key that he wanted to generate. An example of such a key can be found at Excel file. Normally, this file is what the biologist would produce at the start. Because Excel has limited data structuring capability, authors place the key-value pairs in Excel comments attached to a cell associated with the node. This file is saved in Excel's native XML format, then transformed with a Java program into an XML file conforming to our PLD specification (i.e. valid for an XML schema of our design). On the browser the user gets to choose which form of key they prefer to use.

An application processing a key is free to do what it wishes with the information in the PLD Tree. Here the application generates html, pdf, wml and Visual Keys represented as a tree browser, using a java applet. For some of these representations, upon arrival at a taxon, the user can request the backend(s) to offer a descriptive taxon page. In addition, where the backends support some form of a character-by-state search we also provide that.

Programming for this application was by Jacob K. Asiedu

Robert A. Morris, PI ram[at]cs[dot]umb[dot]edu
Robert D. Stevenson, CO-Pi
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