polar_1.ncl:
Default black and white plot.
gsn_csm_contour_map_polar is
the plot interface that creates a cylindrical equidistant plot.
cnLineLabelPlacementMode = "constant", is one of the
three methods
for controlling contour labels. the constant method is the only one in
which the label becomes part of the line.
There are four title strings you can use to label a plot. The
gsnLeftString is
automatically labeled with the long_name of the data, and
gsnRightString is
labeled with the units of the data. These can both be overwritten, or
turned off (by setting them to ""). There is also
gsnCenterString
and the plot title
tiMainString.
res@mpMinLatF and
res@mpMaxLatF are used to limit the extent of the plot
in the southern and northern hemisphere respectively.
gsnPolar allows you to choose a hemisphere. The default is the nothern hemisphere.
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polar_2.ncl:
Adds color and a local time axis.
cnFillOn = True, turns on a color plot.
gsnSpreadColors is
a special resource that tell the plot template to use the full range of
the colormap.
There are many built-in
colormaps
to choose from and many ways of specifying the
color of a plot.
ZeroNegDashLineContour is the special
shea_util.shtml function that will take contours and make the
zero line double thickness, and the negative lines dashed. There
are many other
contour effects you can use.
gsnPolarUT and gsnPolarTime turn on the local time on a polar plot.
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polar_3.ncl:
Manually sets contour levels, turns on contour labels, and puts the
min/max of the data on the plot.
cnLevelSelectionMode = "ManualLevels"
cnMinLevelValF
cnMaxLevelValF
cnLevelSpacingF
are the resources that manually sets the contour levels.
The NCL built-in functions
min and
max allow you to take the min and max of the data.
cnLineLabelsOn = True will turn on the contour line labels. These are turned off
by default on color plots.
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polar_4.ncl:
Demonstrates a panel plot. There are too many nuances associated with
panelling. Please review the CCSM panel example page for details.
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polar_5.ncl:
Demonstrates plotting data on magnetic coordinates
The function mag2latlon (found in
hao_cobntrib.ncl takes data
on magnetic coordinates and changes the named dimensions fixes
the units of the coordinate variables so that the NCL gsn_csm plot
interfaces do not produce error messages.
It is necessary to turn off the cyclic point by setting
gsnAddCyclic to False. The gsn templates automatically add a cyclic point, and
data on the magnetic coordinates already has one.
mpGridAndLimbOn turns on the grid lines.
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polar_6.ncl:
Adds vectors and explicit contour levels.
To effectively view the variable in this example, it was necessary to
explicitly set the contour intervals. This is done with
cnLevelSelectionMode = "Explicit" and providing
values to
cnLevels.
This example draws vectors on top of scalars. For a complete description
of the vector resources used, and other vector options, please check out
the
CCSM vector page
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polar_7.ncl:
Demonstrates interpolating the data to height before plotting.
hao_contrib.ncl contains
the function "zplev_to_height" which we use to interpolate to height
in the
master scripts. Note that this function
requires the create of a logical variable to which you attach the height
value. In the master scripts this variable is also used for other
things.
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