Suitability of DELTA for fruit/seed key; use on Macs

Mike Dallwitz miked at
Tue Dec 13 08:10:48 CET 1994

- From: Susan Mazer

> I am currently working on a photographic field guide to the fruits and 
> seeds of about 1500 Peruvian lowland rainforest species, and I'm 
> interested in the possibility of using Delta to produce a dichotomous 
> key to allow the field identification of these taxa.
> Is this an appropriate/possible application of Delta?
> Is Delta now available for use on Macintosh computers, or only for 
> DOS?
> Where can I look into the purchase of the program?

This is an appropriate application of DELTA, though I strongly suggest 
that you develop an INTKEY (interactive identification) package instead 
of (or at least in addition to) conventional keys. INTKEY could 
comfortably handle 1500 species in a single 'key'.

Our DELTA programs are only available for MS-DOS. A MS-Windows version 
of INTKEY is almost ready for release. The programs will run on DOS and 
Windows emulators on a Mac. We recently did some tests on a Power Mac 
7100/66AV with 16MB of RAM. The speed in DOS/Windows emulation is 
roughly 15% that of a 50MHz 486. The substantially lower speed is no 
problem for most INTKEY operations, which complete almost 
instantaneously. However, the time taken for operations which involve 
scanning the whole data matrix might be regarded as inconvenient. On 
John Lawrence's beetle-larvae data (180 characters, 385 taxa), a check 
of the main DELTA data files took 167sec, and the INTKEY BEST command 
took 145sec in DOS and 120sec in Windows. (Bear in mind, however, that 
you don't need to wait for BEST to complete before choosing a 

The DELTA programs, and several data sets, are available by gopher or 
anonymous ftp from the following Internet hosts. (directory: /pub/delta) (directory: /delta)

The file Index.txt (note the upper-case I) contains a list of the 
available programs and data. To view this file during an ftp session, 
give the ftp commands 'get Index.txt' and '! more < Index.txt'. Most of 
the subdirectories of delta contain a file Download.1st which contains 
information about downloading and installing the files in that 
subdirectory. Files other than .1st, .txt, and .ps must be transmitted 
in binary mode (set by the ftp command 'binary').

The programs are supplied with documentation files, sample data, and a 
list of references. The conditions of use are in a file DELTA.USE, and 
the prices in DELTA.REG. These files are within the self-extracting 
archive file DELTA1 at .EXE.

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Mike Dallwitz
CSIRO Division of Entomology, GPO Box 1700, Canberra ACT 2601, Australia
Internet md at  Phone +61 6 246 4075  Fax +61 6 246 4000

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