ContourPlot example 6
This example demonstrates how to read data from a netCDF file and
create a series of contour plots from the data. This example can be
created using HLU C library calls, HLU FORTRAN library calls, or NCL
commands. The names of the example codes are cn06c.c, cn06f.f, and
View this animation.
This module discusses how to create this plot using HLU function calls
and NCL. This module also shows how to read netCDF data from a file
and produce a series of contour plots. This example reads a subset of
temperature data from a netCDF file, creates a contour plot of the
data, and then repeats this process to produce several frames in a
sequence of time steps. There is no resource file for this example,
as all the resources are set in the source code.
A detailed discussion of how this example works appears in its
The HLU C program that generates this plot is called cn06c.c.
The HLU FORTRAN program that generates this plot is called cn06f.f.
The NCL script that generates this plot is called
The data for this plot is from a netCDF file called contour.cdf.
This example data file contains several geophysical variables including
a four-dimensional temperature variable, T. A subset of this variable is
read from the netCDF file along with latitude and longitude coordinate
variables for each time step.
The data file is located in your NCAR Graphics data directory in a
subdirectory called "cdf". You can get the name of the data directory
by typing "ncargpath data" at your shell prompt. If you have netCDF
installed on your system, then you can change directory to where the
netCDF file resides and type "ncdump -h contour.cdf" to view the
header information for this data file.
The examples are installed in the following locations:
The netCDF data file is installed in the following location:
You can copy this example and run it by typing "ng4ex cn06c", "ng4ex
cn06f", or "ng4ex cn06n". A copy of the source file will be placed in
your current working directory and run automatically for you. You
must have the netCDF library
installed on your system in order to compile the C or FORTRAN version
of this example.
You can view the output NCGM file using the NCAR Graphics ctrans
utility. (For example, to view the file generated from cn06n.ncl, type
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$Revision: 1.13 $ $Date: 1999/03/23 18:34:13 $