Each set of examples starts with a minimal script (for example, "uv300_wind_1.ncl"), and then subsequent scripts ("uv300_wind_2.ncl", "uv300_wind_3.ncl", etc.) build on the previous ones to create a more complex plot.
The following examples show how to use NCL to draw contours of data on
a
All of the "uv300_n.ncl" and "uv300_wind_n.ncl" scripts, and the
"uv300.nc" NetCDF file are in this
uv300_ncl_demo.tar file.
uv300_1.ncl: This example shows how to
create a contour plot of zonal winds on a rectilinear grid.
No plot options are set here, which gives you all the default settings (black line contour plot, land filled in gray, "informational" contour level label at the bottom).
uv300_2.ncl: This example is identical
to the previous one, except options are set to turn on color fill and
increase the size of the plot.
uv300_wind_1.ncl: This example
shows how to create a vector plot of divergent winds. Minimal options
are set to control the length of the vectors, since the default values
are not ideal.
uv300_wind_2.ncl: This example is
identical to the previous one, except options are set to turn on curly
vectors and to change the left subtitle at the top of the plot.
uv300_wind_4.ncl: This example
shows how to overlay vectors on a contour/map plot.
The key to overlaying plots that involve maps is to make the map plot the first argument to the overlay procedure (this is called the "base" plot ). The second argument of overlay should be a non-map plot, but must still be in the same lat/lon space as the base plot.
The following NEMO (Nucleus for
European Modelling of the Ocean) examples show how to use NCL to draw
contours of data on a
The NEMO file was provided with permission by Clotilde Dubois of
Météo-France.
All of the "nemo_n.ncl" scripts and the NEMO NetCDF file are
in this
nemo_ncl_demo.tar.gz
gzipped tar file.
nemo_1.ncl: This example shows how to
create a line contour plot of temperature data on a NEMO grid.
Options are set to zoom in on the area of interest, and to
indicate the lat/lon locations of the data.
nemo_2.ncl: This example is identical to
the previous one, except options are set to turn on color fill and to
double the number of contour levels.
nemo_3.ncl: This example is identical to
the previous one, except options are set to use higher-resolution map outlines,
change the color of the land and ocean, and add a main title.
The
following CAM-SE
examples show how to use NCL to draw contours of data on
an
All of the "camse_n.ncl" scripts and the subsetted CAM-SE NetCDF file
are in this
camse_ncl_demo.tar.gz
gzipped tar file.
camse_1.ncl: This example shows how to
create a line contour plot of temperature data on a CAM-SE grid. The
only options set are to indicate the lat/lon positions of the data,
and to maximize the size of the plot in the PNG file.
camse_2.ncl: This example is identical
to the previous one, except options are set to turn on color fill.
camse_3.ncl: This example is similar
to the previous one, except options are set to use raster contours,
which can be rendered faster than the default smoothed contours.
Raster contours can look blocky if you have a low-resolution grid, but you can smooth them by setting cnRasterSmoothingOn to True.
The color map is also changed in this example, using the "WhiteBlueGreenYellowRed" color table from NCL's collection of predefined color tables.
camse_4.ncl: This example is similar
to the previous one, except the contours are drawn over a Robinson
map projection, and a function was added to create a different color map.
