1.0 Why use netCDF for CD ROM 3.0 of WOCE Global Data set?
All of the WOCE Global Data is now in netCDF format. This data format has many advantages. The most important of which is that it is a self describing, meaning that software packages can directly read the data and determine its structure, the variables names and essential metadata such as the units. This self describing aspect of netCDF file format means that the information needed to ensure accurate work (i.e. reducing the incidence of errors) is available with the data itself. Secondly, it means that programs describe below can read a netCDF file and generate the code needed to read the file whether it be Fortran, C/C++, JAVA or PERL. Thirdly, plotting and analysis packages (e.g. Ferret, IDL, MATLAB) can directly read the netCDF files for plotting or analysis. In many of these packages the axes can be labeled without intervention from the user
Although there is an initial learning curve for the inexperienced netCDF user, high efficiency in reading netCDF files and multiple data can be readily achieved as shown in the examples below. These savings translate to more time for analyzing data and addressing the synthesis of the WOCE Global Data.
I have assumed that netCDF libraries have already been installed on your system. They can be obtained from www.unidata.ucar.edu/Software.html or www.unidata.ucar.edu/packages/netcdf/index.html and are available for Unix, Windows and Macintosh based systems. This site also contains excellent description of the Fortran (also Fortran 90), JAVA and PERL interfaces for netCDF files. Freely available and commercial software that uses netCDF for input are also listed at these sites and includes products such as Ferret, GMT and GrADs and commercial products such as MATLAB, NCAR Graphics, IDL and others. Here we focus on reading netCDF files with ncBrowse, Matlab, IDL, Fortran, C, ncdump, and Ferret.
The WOCE Global Data V3 are now in a
compliant format. This means that the variables names associated
with the data, the attributes of the data and the time convention follow a
common standard for all the different data types within the WOCE Global Data
set, and also are common to other data sets that are used by the oceanographic
and meteorology communities.