Click here to download this notebook.

Raw data comparison

[2]:

from casys.readers import CLSTableReader

from casys import CasysPlot, DateHandler, Field, NadirData, PlotParams

NadirData.enable_loginfo()

Compare Sla with latitude

Select your data source

[3]:

# Reader definition
table_name = "TABLE_C_J3_B_GDRD"
start = DateHandler("2019-06-01 05:30:00")
end = DateHandler("2019-06-03 05:30:00")

reader = CLSTableReader(
    name=table_name,
    date_start=start,
    date_end=end,
    time="time",
    longitude="LONGITUDE",
    latitude="LATITUDE",
)

# Data container definition
ad = NadirData(source=reader)

Define your diagnostic fields

[4]:

sla = Field(
    name="sla",
    source="ORBIT.ALTI - RANGE.ALTI - MEAN_SEA_SURFACE.MODEL.CNESCLS15",
    unit="m",
)
latitude = ad.fields["LATITUDE"]

Set up your diagnostic

Using the add_raw_comparison method:

[5]:

ad.add_raw_comparison(name="Sla / Latitude", x=latitude, y=sla)

Compute it

[6]:

ad.compute()

2025-05-14 11:00:04 INFO    Reading ['LATITUDE', 'sla']
2025-05-14 11:00:05 INFO    Computing done.

Visualize it

[7]:

raw_comp_sla_lat_plot = CasysPlot(data=ad, data_name="Sla / Latitude")

raw_comp_sla_lat_plot.show()

[7]:

../_images/examples_example_basic_raw_data_comparison_14_0.png

Compare SWH Ku band and C band (2D comparison)

[8]:

var_range_std_ku = Field(
    name="range_std_ku", source="IIF(FLAG_VAL.ALTI==0, RANGE_STD.ALTI,DV)", unit="m"
)
var_range_std_c = Field(
    name="range_std_c", source="IIF(FLAG_VAL.ALTI==0, RANGE_STD.ALTI.B2,DV)", unit="m"
)
ad.add_raw_comparison(
    name="SWH Ku Band / SWH C Band", x=var_range_std_c, y=var_range_std_ku
)
ad.compute()

2025-05-14 11:00:05 INFO    Reading ['range_std_c', 'range_std_ku']
2025-05-14 11:00:06 INFO    Computing done.

[9]:

ku_c_comp_plot = CasysPlot(
    data=ad, data_name="SWH Ku Band / SWH C Band", plot_params=PlotParams(line_style="")
)

ku_c_comp_plot.show()

[9]:

../_images/examples_example_basic_raw_data_comparison_17_0.png

Compare SWH Ku band with C Band along longitude (3D comparison)

[10]:

ad.add_raw_comparison(
    name="SWH Ku Band / SWH C Band / LATITUDE",
    x=latitude,
    y=var_range_std_c,
    z=var_range_std_ku,
)
ad.compute()

2025-05-14 11:00:06 INFO    Computing done.

2D visualization

[11]:

ku_c_comp_plot = CasysPlot(
    data=ad,
    data_name="SWH Ku Band / SWH C Band / LATITUDE",
)

ku_c_comp_plot.show()

[11]:

../_images/examples_example_basic_raw_data_comparison_21_0.png

3D visualization

[12]:

ku_c_comp_plot = CasysPlot(
    data=ad,
    data_name="SWH Ku Band / SWH C Band / LATITUDE",
    plot="3d",
)

ku_c_comp_plot.show()

[12]:

../_images/examples_example_basic_raw_data_comparison_23_0.png

Additional information about along track comparison can be found on this page.