ContourPlot example 9
This example can be created using HLU C library calls, HLU FORTRAN
library calls, or NCL. It reads data from a netCDF file and creates a
series of contour plots from the data. The example shows a series of
plots of surface pressure. The names of the example codes that create
this plot are cn09c.c, cn09f.f, and cn09n.ncl.
View this animation.
This module discusses how to create the previous 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 surface pressure 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 source
The HLU C program that generates this plot is called cn09c.c.
The HLU FORTRAN program that generates this plot is called cn09f.f.
The NCL script that generates this plot is called cn09n.ncl.
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 pressure variable, PS1. 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 cn09c", "ng4ex
cn09f", or "ng4ex cn09n". A copy of the source file and resource file
will be placed in your current working directory. The source code will
be compiled and automatically run 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 cn09n.ncl,
type "ctrans cn09n.ncgm".)
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$Revision: 1.11 $ $Date: 1999/03/23 18:34:14 $