Perl interface to the (deprecated) netCDF 2 API
XS Perl Makefile Other

README.md

NetCDF Perl

Greetings! This file briefly describes the Unidata netCDF Perl package.

Table of Contents

Notice of Deprecation

The netCDF Perl package is no longer being actively maintained by the Unidata program center. Unidata will continue to provide support for Unidata netCDF Perl.

Introduction

The netCDF Perl package is a perl extension module for scientific data access via the netCDF API.

The netCDF Perl package is a perl extension for accessing netCDF datasets based on version 2 of the netCDF package (netCDF-2). For example, the following netCDF-2 actions:

  1. Open dataset "foo.nc";

  2. Write a 2 x 3 array of double-precision values into the starting corner of the first variable; and

  3. Close the dataset.

can be accomplished by the following C fragment:

        int     ncid = ncopen("foo.nc", NC_WRITE);
        int     varid = 0;
        long    start[2], count[2];
        double  values[6];

        ncid = ncopen("foo.nc", NC_WRITE);

        start[0] = 0;
        start[1] = 0;
        count[0] = 2;
        count[1] = 3;

        values[0] = 0.0;
        values[1] = 1.0;
        values[2] = 2.0;
        values[3] = 3.0;
        values[4] = 4.0;
        values[5] = 5.0;

        ncvarput(ncid, varid, start, count, values);

        ncclose(ncid);

or by this equivalent perl fragment:

        use NetCDF;

        $ncid = NetCDF::open("foo.nc", NetCDF::WRITE);
        $varid = 0;
        @start = (0, 0);
        @count = (2, 3);
        @values = (0, 1, 2, 3, 4, 5);
        NetCDF::varput($ncid, $varid, \@start, \@count, \@values);
        NetCDF::close($ncid);

There are perl-callable functions for all appropriate functions of the netCDF-2 API.

netCDF-2 vs. netCDF-3

Currently, the netCDF Perl extension module is implemented using version 2 of the netCDF API (netCDF-2). On 1997-05-16, version 3 of the netCDF package was released (netCDF-3). This newer version, however, contains a netCDF-2 backward compatibility interface. Thus, with a few minor changes already made, netCDF Perl works with netCDF-3 as well as netCDF-2.

Users should be aware, however, that the netCDF Perl user-interface is based on netCDF-2. In particular, the netCDF Perl documentation doesn't describe the netCDF Perl interface in detail but instead describes the differences between it and the netCDF-2 interface. The intention was that users would use the netCDF Perl and netCDF-2 documentation together in order to program using netCDF Perl.

With the deprecation of the netCDF-2 interface, this has become slightly problematical -- but not unworkable. The solution is to ensure the availability of the netCDF-2 documentation.

The Unidata netCDF library web site contains user guides, manual pages, information on the various versions of netCDF, and more.

Availability

Unidata netCDF Perl

In addition to the source here on GitHub, Unidata netCDF Perl is freely available for download at: ftp://ftp.unidata.ucar.edu/pub/netcdf-perl/

Other Sources

Note: The following are third-party and have not been verified or validated by the Unidata Program Center.

RedHat RPM & ncmanipulate
Alan Iwi's source and binary RPMs for RedHat Linux and ncmanipulate module to manipulate NetCDF files.

Fedora Installation
Fedora provides a package called "netcdf-perl".

PDL::NetCDF
Doug Hunt's perl interface which uses the PDL (perl data language) extension.

Installation

See the file INSTALL in the top-level directory of the netCDF Perl distribution for instructions on how to incorporate netCDF Perl into your perl utility.

Note: You will need write access to your installed perl(1) libraries in order to install netCDF Perl.

The netCDF Perl manual page details how to use the NetCDF Perl package.

Read the list of known problems with the netCDF Perl package.

Support & Mailing List

Requesting Support

Request support from Unidata netCDF Perl developers: support-netcdf-perl@unidata.ucar.edu

You can also view current and past netCDF perl support questions answered by Unidata developers.

Defunct Mailing List

Perl had a community mailing list associated with it at one time. The mailing list is no longer active, but the list archive is still available for reference.

Known Problems

netCDFPerl doesn't install under OSF/1

make install might fail to install the netCDFPerl package under OSF/1. This might be due to a bug in make(1). The solution is to move the line

.PRECIOUS: Makefile

in the file perl/Makefile to after the all target.