Graphs

Example 27 - graph plot

import cf, cfplot as cfp
f=cf.read('/opt/graphics/cfplot_data/ggap.nc')[1]
g=f.collapse('X: mean')
cfp.lineplot(g.subspace(pressure=100), marker='o', color='blue',\
             title='Zonal mean zonal wind at 100mb')

Other valid markers are:

‘.’ point

‘,’ pixel

‘o’ circle

‘v’ triangle_down

‘^’ triangle_up

‘<’ triangle_left

‘>’ triangle_right

‘1’ tri_down

‘2’ tri_up

‘3’ tri_left

‘4’ tri_right

‘8’ octagon

‘s’ square

‘p’ pentagon

‘*’ star

‘h’ hexagon1

‘H’ hexagon2

‘+’ plus

‘x’ x

‘D’ diamond

‘d’ thin_diamond

Example 28 - Line and legend plot

import cf, cfplot as cfp
f=cf.read('/opt/graphics/cfplot_data/ggap.nc')[1]
g=f.collapse('X: mean')
xticks=[-90,-75,-60,-45,-30,-15,0,15,30,45,60,75,90]
xticklabels=['90S','75S','60S','45S','30S','15S','0','15N','30N','45N','60N','75N','90N']
xpts=[-30, 30, 30, -30, -30]
ypts=[-8, -8, 5, 5, -8]

cfp.gset(xmin=-90, xmax=90, ymin=-10, ymax=50)
cfp.gopen()
cfp.lineplot(g.subspace(pressure=100), marker='o', color='blue',\
             title='Zonal mean zonal wind', label='100mb')
cfp.lineplot(g.subspace(pressure=200), marker='D', color='red',\
             label='200mb', xticks=xticks, xticklabels=xticklabels,\
             legend_location='upper right')
cfp.plotvars.plot.plot(xpts,ypts, linewidth=3.0, color='green')
cfp.plotvars.plot.text(35, -2, 'Region of interest', horizontalalignment='left')
cfp.gclose()

In this example a plot with user specified axes is made. The new axis labelling and legend must be added in the final call to lineplot. All previous calls to lineplot must have set the label attribute so that the line labels are ready for making the legend. A text box and some text are added to a region of interest. The cfp.plotvars.plot object contains the plot and will accept normal Matplotlib plotting commands.

Valid locations for the legend_location keyword are:

‘right’

‘center left’

‘upper right’

‘lower right’

‘best’

‘center’

‘lower left’

‘center right’

‘upper left’

‘upper center’

‘lower center’

When making a call to lineplot the following parameters overide any predefined CF defaults:

title=None - plot title

xunits=None - x units

yunits=None - y units

xname=None - x name

yname=None - y name

xticks=None - x ticks

xticklabels=None - x tick labels

yticks=None - y ticks

yticklabels - y tick labels

Example 29 - Global average annual temperature

In this example we subset a time data series of global temperature, area mean the data, convert to Celsius and plot a linegraph.

When using gset to set the limits on the plotting axes and a time axis pass time strings to give the limits i.e. cfp.gset(xmin = ‘1980-1-1’, xmax = ‘1990-1-1’, ymin = 285, ymax = 295)

The correct date format is ‘YYYY-MM-DD’ or ‘YYYY-MM-DD HH:MM:SS’ - anything else will give unexpected results.

import cf, cfplot as cfp
f=cf.read('/opt/graphics/cfplot_data/tas_A1.nc')[0]
temp=f.subspace(time=cf.wi(cf.dt('1900-01-01'), cf.dt('1980-01-01')))
temp_annual=temp.collapse('T: mean', group=cf.Y())
temp_annual_global=temp_annual.collapse('area: mean', weights='area')
temp_annual_global.Units -= 273.15
cfp.lineplot(temp_annual_global, title='Global average annual temperature', color='blue')

Example 30 - Two axis plotting

In this example we plot two x-axes, one with zonal mean zonal wind data and one with temperature data. Somewhat confusingly the option for a twin x-axis is twiny=True. This is a Matplotlib keyword which has been adopted within teh cf-plot code.

import cf, cfplot as cfp
tol=cf.RTOL(1e-5)
f=cf.read('/opt/graphics/cfplot_data/ggap.nc')[1]
u=f.collapse('X: mean')
u1=u.subspace(Y=-61.12099075)
u2=u.subspace(Y=0.56074494)

g=cf.read('/opt/graphics/cfplot_data/ggap.nc')[0]
t=g.collapse('X: mean')
t1=t.subspace(Y=-61.12099075)
t2=t.subspace(Y=0.56074494)

cfp.gopen()
cfp.gset(-30, 30, 1000, 0)
cfp.lineplot(u1,color='r')
cfp.lineplot(u2, color='r')

cfp.gset(190, 300, 1000, 0, twiny=True)
cfp.lineplot(t1,color='b')
cfp.lineplot(t2, color='b')

cfp.gclose()