PGPLOT module for Perl
----------------------

Karl Glazebrook, Anglo-Australian Observatory

kgb@aaoepp.aao.gov.au

Module Version 2.0  January 2nd, 1997

[see file CHANGES for new features in 2.0 version]

This module allows the use of the the PGPLOT graphics library from the
popular Perl scripting language. PGPLOT makes it very easy to process
and plot data using the powerful file and text manipulation facilites
built in to Perl.  Perl provides a superset of the features of the
useful UNIX utilities awk and sed and is the `Swiss-Army Chainsaw' of
UNIX programming.

Because Perl is a scripting language a program can be changed and rerun
to instantly see the effect on a plot.  This makes program development
a lot faster and much more fun than when using PGPLOT from fully
compiled languages such as C or FORTRAN. Users of MONGO and SM will be
familiar with this style of programming. Perl also allows you to create
advanced World Wide Web page features and/or routinely do system
management tasks (Perl handles regular expressions, files and sockets
with equal ease).

PGPLOT is a very popular library for plotting astronomical data. (As a
glance through any issue of ApJ or MNRAS will confirm.) I have always
found that with PGPLOT I could produced far nicer and more complex
plots than I could with MONGO but it was always harder to use because
it had to be done from C or FORTRAN. SM is a nice package, but the
language is primitive in comparison with Perl and it is not free
software.

The PGPLOT module for Perl is free software and provides a complete
Perl interface to all of the PGPLOT library functions. The current
module version is 2.0, it requires Perl 5.003 (or greater) and builds
against the 5.1.2 version of the PGPLOT C/FORTRAN library.

More information may be obtained from the 'pgperl' Web home page:

http://www.aao.gov.au/local/www/kgb/pgperl

The home ftp sites are:

ftp.aao.gov.au:/pub/pgperl/ located in Australia. 

ftp.ast.cam.ac.uk:/pub/kgb/pgperl/ located in Cambridge, U.K. 

linux.nrao.edu:/pub/packages/pgperl/ located in the U.S. 

The core module is also available from The Comprehensive Perl Archive 
(CPAN) network in the directory CPAN/modules/by-module/PGPLOT.

Installation
------------

1) First you must install the pgplot libraries. There are
   two methods:

   (i) The source can be obtained from the ftp site astro.caltech.edu
   in directory /pub/pgplot. Alternatively see the home ftp sites
   above. To build pgplot you need a FORTRAN compiler - the free
   compiler GNU-77 works just fine (versions 5.0-18 and above).

   (ii) Obtain a pre-built set of libraries from one of the home ftp
   sites above in the sub-directory pgplot-binaries/. Currently
   SunOS/Solaris/Linux-ELF/OSF1/HPUX binaries are available. Follow the
   instructions in the file README, which comes with the libraries, for
   installation.

2) Download and unpack the module. Then follow the standard Perl build
   procedure:

   perl Makefile.PL
   make
   make test
   make install

   [When you run 'make test' you will be prompted for a graphics device.
    Try /XSERVE for a X11 display.]


Problems
--------

You may experience problems if the module does not 'know' about
the FORTRAN/C interface on your architecture. Please contact me
and I will try to help. Alternatively - install GNU-77! (You gnu
it makes sense...)