Objectives

  • Set-up a cartesian projection for the Cross section
  • Configure the axis
  • Load a netCDF file, and understand the information needed by Magics.
  • Apply a shading
  • Position the legend box
  • Add a text.

You will need to download

 

 

Setting of the cartesian projection

We want to show our Cross section in the following cartesian system:

Have a look at the  subpage documentation to learn how to setup a cartesian projection .

We just have to add 2 axis (1 vertical, 1 horizontal ) to materialise it on the plot. For backward compatibility, we have only one maxis object, the orientation is defined using the parameter axis_orientation.

Useful subpage parameters

subpage_map_projection

subpage_x_axis_type
subpage_y_axis_type
subpage_x_min_latitude
subpage_x_min_longitude
subpage_x_max_latitude
subpage_x_max_longitude
subpage_y_min
subpage_y_max
from Magics.macro import *
#setting the output 
output = output(    
                output_formats = ['png'],
                output_name = "xsect_step1",
                output_name_first_page_number = "off"
        )
# Setting the cartesian view
projection = mmap(
        subpage_map_projection='cartesian',
        subpage_x_axis_type='geoline',
        subpage_y_axis_type='logarithmic',
        subpage_x_min_latitude=50.,
        subpage_x_max_latitude=30.,
        subpage_x_min_longitude=-90.,
        subpage_x_max_longitude=-60.,
        subpage_y_min=1020.,
        subpage_y_max=200.,
        )
# Vertical axis
vertical = maxis(
        axis_orientation='vertical',
        )
# Horizontal axis
horizontal = maxis(
        axis_orientation='horizontal',
        )
        
plot(output, projection, horizontal, vertical)

 

Adjusting the axis

By specialising the axis, you can improve your axis visualisation.

Have a look at the Axis Documentation  to browse the possibilities.

Now, try to improve the readability of the line by specialising the horizontal axis.

Useful axis parameters

axis_type

axis_tick_label_height
axis_tick_label_colour
axis_grid
axis_title
from Magics.macro import *
#setting the output 
output = output(    
                output_formats = ['png'],
                output_name = "xsect_step2",
                output_name_first_page_number = "off"
        )
# Setting the cartesian view
projection = mmap(
        subpage_map_projection='cartesian',
        subpage_x_axis_type='geoline',
        subpage_y_axis_type='logarithmic',
        subpage_x_min_latitude=50.,
        subpage_x_max_latitude=30.,
        subpage_x_min_longitude=-90.,
        subpage_x_max_longitude=-60.,
        subpage_y_min=1020.,
        subpage_y_max=200.,
        )
# Vertical axis
vertical = maxis(
        axis_orientation='vertical',
        axis_grid='on',
        axis_type='logarithmic',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid_colour='charcoal',
        axis_grid_line_style='dash',
        axis_title='on',
        axis_title_text='Pressure',
        axis_title_height=0.6,
        )
# Horizontal axis
horizontal = maxis(
        axis_orientation='horizontal',
        axis_type='geoline',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid='on',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_line_style='dash',
        )
plot(output, projection, horizontal, vertical)

 

 

Loading the netCDF data

In this exercise, we want to visualise a matrix stored in a netCDF file. netCDF is a very generic format, and can contain a lot of data. We will  need to set up some information in order to explain to Magics which variable to plot, and how to interpret it.

The mnetcdf data action comes with a parameter list that can be found in the  netCDF Input Page.

But first, let's see what is inside our netCDF Data 

netCDF section {
dimensions:
        levels = 85 ;
        longitude = 144 ;
        latitude = 144 ;
        p15220121030000000000001_1 = 2 ;
        p15220121030000000000001_2 = 144 ;
        orography_x_values = 144 ;
        orography_y1_values = 144 ;
        orography_y2_values = 144 ;
variables:
        double levels(levels) ;
        double longitude(longitude) ;
        double latitude(latitude) ;
        double p13820121030000000000001(levels, longitude) ;

We want to display the variable p1382012103000000000000, and inform Magics that the dimensions of the matrix are described in the 2 variables levels and longitude.

The range of the vorticity values is quite small, then we would like to apply a scaling factor of 100000.

We will then just apply a basic contouring.

Useful netCDF parameters

netcdf_filename

netcdf_value_variable
netcdf_field_scaling_factor
netcdf_y_variable
netcdf_x_variable
netcdf_x_auxiliary_variable
from Magics.macro import *
#setting the output 
output = output(    
                output_formats = ['png'],
                output_name = "xsect_step3",
                output_name_first_page_number = "off"
        )
# Setting the cartesian view
projection = mmap(
        subpage_map_projection='cartesian',
        subpage_x_axis_type='geoline',
        subpage_y_axis_type='logarithmic',
        subpage_x_min_latitude=50.,
        subpage_x_max_latitude=30.,
        subpage_x_min_longitude=-90.,
        subpage_x_max_longitude=-60.,
        subpage_y_min=1020.,
        subpage_y_max=200.,
        )
# Vertical axis
vertical = maxis(
        axis_orientation='vertical',
        axis_grid='on',
        axis_type='logarithmic',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_reference_line_style='solid',
        axis_grid_reference_thickness=1,
        axis_grid_line_style='dash',
        axis_title='on',
        axis_title_text='Pressure',
        axis_title_height=0.6,
        )
# Horizontal axis
horizontal = maxis(
        axis_orientation='horizontal',
        axis_type='geoline',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid='on',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_line_style='dash',
        )
# Definition of the netCDF data and interpretation
data = mnetcdf(netcdf_filename = "section.nc",
      netcdf_value_variable = "p13820121030000000000001",
      netcdf_field_scaling_factor = 100000.,
      netcdf_y_variable = "levels",
      netcdf_x_variable = "longitude",
      netcdf_x_auxiliary_variable = "latitude"
    )
contour = mcont()
plot(output, projection, horizontal, vertical, data, contour)

Creating a nice shading

Now, we just create a nice polygon shading.

The list of levels we want to use is : [-200., -100., -75., -50., -30., -20., -15., -13., -11., -9., -7., -5., -3., -1., 1., 3., 5.,  7., 9., 11., 13., 15., 20., 30., 50., 75., 100., 200].

and the list of colours is : ["rgb(0,0,0.3)", "rgb(0,0,0.5)", "rgb(0,0,0.7)", "rgb(0,0,0.9)", "rgb(0,0.15,1)", "rgb(0,0.3,1)", "rgb(0,0.45,1)", "rgb(0,0.6,1)", "rgb(0,0.75,1)", "rgb(0,0.85,1)", "rgb(0.2,0.95,1)", "rgb(0.45,1,1)", "rgb(0.75,1,1)", "none", "rgb(1,1,0)","rgb(1,0.9,0)", "rgb(1,0.8,0)", "rgb(1,0.7,0)", "rgb(1,0.6,0)", "rgb(1,0.5,0)", "rgb(1,0.4,0)", "rgb(1,0.3,0)", "rgb(1,0.15,0)", "rgb(0.9,0,0)", "rgb(0.7,0,0)", "rgb(0.5,0,0)", "rgb(0.3,0,0)"],

Do not forget to trun the legend on ...

You could quickly check Contour Documentation

Useful contour parameters

contour_level_selection_type

contour_level_list
contour_shade

contour_shade_method

contour_shade_colour_method

contour_shade_colour_list
legend
from Magics.macro import *
#setting the output 
output = output(    
                output_formats = ['png'],
                output_name = "xsect_step3",
                output_name_first_page_number = "off"
        )
# Setting the cartesian view
projection = mmap(
        subpage_map_projection='cartesian',
        subpage_x_axis_type='geoline',
        subpage_y_axis_type='logarithmic',
        subpage_x_min_latitude=50.,
        subpage_x_max_latitude=30.,
        subpage_x_min_longitude=-90.,
        subpage_x_max_longitude=-60.,
        subpage_y_min=1020.,
        subpage_y_max=200.,
        )
# Vertical axis
vertical = maxis(
        axis_orientation='vertical',
        axis_grid='on',
        axis_type='logarithmic',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_reference_line_style='solid',
        axis_grid_reference_thickness=1,
        axis_grid_line_style='dash',
        axis_title='on',
        axis_title_text='Pressure',
        axis_title_height=0.6,
        )
# Horizontal axis
horizontal = maxis(
        axis_orientation='horizontal',
        axis_type='geoline',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid='on',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_line_style='dash',
        )
# Definition of the netCDF data and interpretation
data = mnetcdf(netcdf_filename = "section.nc",
      netcdf_value_variable = "p13820121030000000000001",
      netcdf_field_scaling_factor = 100000.,
      netcdf_y_variable = "levels",
      netcdf_x_variable = "longitude",
      netcdf_x_auxiliary_variable = "latitude"
    )
contour = mcont(contour_highlight= "off",
    contour_hilo= "off",
    contour_label= "off",
    legend='on',
    contour_level_list= [-200., -100., -75., -50., -30., -20., 
        -15., -13., -11., -9., -7., -5., -3., -1., 1., 3., 5., 
        7., 9., 11., 13., 15., 20., 30., 50., 75., 100., 200],
    contour_level_selection_type= "level_list",
    contour_shade= "on",
    contour_shade_colour_list= ["rgb(0,0,0.3)", "rgb(0,0,0.5)", 
        "rgb(0,0,0.7)", "rgb(0,0,0.9)", "rgb(0,0.15,1)", 
        "rgb(0,0.3,1)", "rgb(0,0.45,1)", "rgb(0,0.6,1)", 
        "rgb(0,0.75,1)", "rgb(0,0.85,1)", "rgb(0.2,0.95,1)", 
        "rgb(0.45,1,1)", "rgb(0.75,1,1)", "none", "rgb(1,1,0)", 
        "rgb(1,0.9,0)", "rgb(1,0.8,0)", "rgb(1,0.7,0)", 
        "rgb(1,0.6,0)", "rgb(1,0.5,0)", "rgb(1,0.4,0)", 
        "rgb(1,0.3,0)", "rgb(1,0.15,0)", "rgb(0.9,0,0)", 
        "rgb(0.7,0,0)", "rgb(0.5,0,0)", "rgb(0.3,0,0)"],
    contour_shade_colour_method= "list",
    contour_shade_method= "area_fill")
plot(output, projection, horizontal, vertical, data, contour)

Position the legend

By default, the legend is is positioned at the top of the plot. In this  exercise we want to put see our legend on a column mode on the right of the plot.

The Information about the positional mode can be found in the Legend Documentation

Useful legend parameters

legend

legend_display_type

legend_box_mode

legend_box_x_position

legend_box_y_position

legend_box_x_length

legend_box_y_length
legend_box_blanking
legend_border
from Magics.macro import *
#setting the output 
output = output(    
                output_formats = ['png'],
                output_name = "xsect_step5",
                output_name_first_page_number = "off"
        )
# Setting the cartesian view
projection = mmap(
        subpage_map_projection='cartesian',
        subpage_x_axis_type='geoline',
        subpage_y_axis_type='logarithmic',
        subpage_x_min_latitude=50.,
        subpage_x_max_latitude=30.,
        subpage_x_min_longitude=-90.,
        subpage_x_max_longitude=-60.,
        subpage_y_min=1020.,
        subpage_y_max=200.,
        )
# Vertical axis
vertical = maxis(
        axis_orientation='vertical',
        axis_grid='on',
        axis_type='logarithmic',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_reference_line_style='solid',
        axis_grid_reference_thickness=1,
        axis_grid_line_style='dash',
        axis_title='on',
        axis_title_text='Pressure',
        axis_title_height=0.6,
        )
# Horizontal axis
horizontal = maxis(
        axis_orientation='horizontal',
        axis_type='geoline',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid='on',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_line_style='dash',
        )
# Definition of the netCDF data and interpretation
data = mnetcdf(netcdf_filename = "section.nc",
      netcdf_value_variable = "p13820121030000000000001",
      netcdf_field_scaling_factor = 100000.,
      netcdf_y_variable = "levels",
      netcdf_x_variable = "longitude",
      netcdf_x_auxiliary_variable = "latitude"
    )
contour = mcont(contour_highlight= "off",
    contour_hilo= "off",
    contour_label= "off",
    legend='on',
    contour_level_list= [-200., -100., -75., -50., -30., -20., 
        -15., -13., -11., -9., -7., -5., -3., -1., 1., 3., 5., 
        7., 9., 11., 13., 15., 20., 30., 50., 75., 100., 200],
    contour_level_selection_type= "level_list",
    contour_shade= "on",
    contour_shade_colour_list= ["rgb(0,0,0.3)", "rgb(0,0,0.5)", 
        "rgb(0,0,0.7)", "rgb(0,0,0.9)", "rgb(0,0.15,1)", 
        "rgb(0,0.3,1)", "rgb(0,0.45,1)", "rgb(0,0.6,1)", 
        "rgb(0,0.75,1)", "rgb(0,0.85,1)", "rgb(0.2,0.95,1)", 
        "rgb(0.45,1,1)", "rgb(0.75,1,1)", "none", "rgb(1,1,0)", 
        "rgb(1,0.9,0)", "rgb(1,0.8,0)", "rgb(1,0.7,0)", 
        "rgb(1,0.6,0)", "rgb(1,0.5,0)", "rgb(1,0.4,0)", 
        "rgb(1,0.3,0)", "rgb(1,0.15,0)", "rgb(0.9,0,0)", 
        "rgb(0.7,0,0)", "rgb(0.5,0,0)", "rgb(0.3,0,0)"],
    contour_shade_colour_method= "list",
    contour_shade_method= "area_fill")
legend = mlegend(legend='on', 
    legend_display_type='continuous', 
    legend_text_colour='charcoal',         
    legend_text_font_size=0.4, 
    legend_box_mode = "positional",
    legend_box_x_position = 27.00,
    legend_box_y_position = 3.00,
    legend_box_x_length = 2.00,
    legend_box_y_length = 13.00,
    legend_box_blanking = "on",
    legend_border = "on",
    legend_border_colour='charcoal')
 plot(output, projection, horizontal, vertical, data, contour, legend)

add a Title

Last thing to do here .. We add a title to the top..

Here we will use a combination of User text and automatic text ( read from the netCDF global attribute title)

To get the automatic title, you have to use the following tag <magics_title/>

Check the Text Plotting Page for more information

Useful Text parameters

text_lines

text_font_size
text_colour
text_font_style
from Magics.macro import *
#setting the output 
output = output(    
                output_formats = ['png'],
                output_name = "xsect_step6",
                output_name_first_page_number = "off"
        )
# Setting the cartesian view
projection = mmap(
        subpage_map_projection='cartesian',
        subpage_x_axis_type='geoline',
        subpage_y_axis_type='logarithmic',
        subpage_x_min_latitude=50.,
        subpage_x_max_latitude=30.,
        subpage_x_min_longitude=-90.,
        subpage_x_max_longitude=-60.,
        subpage_y_min=1020.,
        subpage_y_max=200.,
        )
# Vertical axis
vertical = maxis(
        axis_orientation='vertical',
        axis_grid='on',
        axis_type='logarithmic',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_reference_line_style='solid',
        axis_grid_reference_thickness=1,
        axis_grid_line_style='dash',
        axis_title='on',
        axis_title_text='Pressure',
        axis_title_height=0.6,
        )
# Horizontal axis
horizontal = maxis(
        axis_orientation='horizontal',
        axis_type='geoline',
        axis_tick_label_height=0.4,
        axis_tick_label_colour='charcoal',
        axis_grid='on',
        axis_grid_colour='charcoal',
        axis_grid_thickness=1,
        axis_grid_line_style='dash',
        )
# Definition of the netCDF data and interpretation
data = mnetcdf(netcdf_filename = "section.nc",
      netcdf_value_variable = "p13820121030000000000001",
      netcdf_field_scaling_factor = 100000.,
      netcdf_y_variable = "levels",
      netcdf_x_variable = "longitude",
      netcdf_x_auxiliary_variable = "latitude"
    )
contour = mcont(contour_highlight= "off",
    contour_hilo= "off",
    contour_label= "off",
    legend='on',
    contour_level_list= [-200., -100., -75., -50., -30., -20., 
        -15., -13., -11., -9., -7., -5., -3., -1., 1., 3., 5., 
        7., 9., 11., 13., 15., 20., 30., 50., 75., 100., 200],
    contour_level_selection_type= "level_list",
    contour_shade= "on",
    contour_shade_colour_list= ["rgb(0,0,0.3)", "rgb(0,0,0.5)", 
        "rgb(0,0,0.7)", "rgb(0,0,0.9)", "rgb(0,0.15,1)", 
        "rgb(0,0.3,1)", "rgb(0,0.45,1)", "rgb(0,0.6,1)", 
        "rgb(0,0.75,1)", "rgb(0,0.85,1)", "rgb(0.2,0.95,1)", 
        "rgb(0.45,1,1)", "rgb(0.75,1,1)", "none", "rgb(1,1,0)", 
        "rgb(1,0.9,0)", "rgb(1,0.8,0)", "rgb(1,0.7,0)", 
        "rgb(1,0.6,0)", "rgb(1,0.5,0)", "rgb(1,0.4,0)", 
        "rgb(1,0.3,0)", "rgb(1,0.15,0)", "rgb(0.9,0,0)", 
        "rgb(0.7,0,0)", "rgb(0.5,0,0)", "rgb(0.3,0,0)"],
    contour_shade_colour_method= "list",
    contour_shade_method= "area_fill")
legend = mlegend(legend='on', 
    legend_display_type='continuous', 
    legend_text_colour='charcoal',         
    legend_text_font_size=0.4, 
    legend_box_mode = "positional",
    legend_box_x_position = 27.00,
    legend_box_y_position = 3.00,
    legend_box_x_length = 2.00,
    legend_box_y_length = 13.00,
    legend_box_blanking = "on",
    legend_border = "on",
    legend_border_colour='charcoal')
title = mtext(
        text_lines= ['Example of Xsection to demonstrate the use of netCDF data...', 
        '<magics_title/>'],
        text_html= 'true',
        text_justification= 'left',
        text_font_size= 0.8,
        text_colour= 'charcoal',
        )

plot(output, projection, horizontal, vertical, data, contour, legend, title)

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