Tephi reference documentation¶

The tephi module provides tephigram plotting of pressure, temperature and wind barb data.

Warning

This is a beta release module and is liable to change.

In this module:

loadtxt

Locator

Tephigram

tephi.loadtxt(*filenames, **kwargs)¶

Load one or more text files of pressure, temperature, wind speed and wind direction value sets.

Each line should contain, at minimum, a single pressure value (mb or hPa), and a single temperature value (degC), but may also contain a dewpoint value (degC), wind speed (knots) and wind direction value (degrees from north).

Note that blank lines and comment lines beginning with a ‘#’ are ignored.

For example:

>>> import os.path
>>> import tephi

>>> winds = os.path.join(tephi.DATA_DIR, 'barbs.txt')
>>> columns = ('pressure', 'dewpoint', 'wind_speed', 'wind_direction')
>>> data = tephi.loadtxt(winds, column_titles=columns)
>>> pressure = data.pressure
>>> dews = data.dewpoint
>>> wind_speed = data.wind_speed
>>> wind_direction = data.wind_direction

See also

numpy.loadtxt().

Args:

filenames: one or more filenames.

Kwargs:

column_titles:
List of iterables, or None. If specified, should contain one title string for each column of data per specified file. If all of multiple files loaded have the same column titles, then only one tuple of column titles need be specified.
delimiter:
The string used to separate values. This is passed directly to np.loadtxt(), which defaults to using any whitespace as delimiter if this keyword is not specified.
dtype:
The datatype to cast the data in the text file to. Passed directly to np.loadtxt().

Returns:: A collections.namedtuple() instance containing one tuple, named with the relevant column title if specified, for each column of data in the text file loaded. If more than one file is loaded, a sequence of namedtuples is returned.

Determine the fixed step axis tick locations when called with a tick range.

class tephi.Locator(step)¶

Determine the fixed step axis tick locations when called with a tick range.

Generate a tephigram of one or more pressure and temperature data sets.

class tephi.Tephigram(figure=None, isotherm_locator=None, dry_adiabat_locator=None, anchor=None)¶
Generate a tephigram of one or more pressure and temperature data sets.
plot(data, **kwargs)¶
Plot the environmental lapse rate profile of the pressure and temperature data points.

The pressure and temperature data points are transformed into potential temperature and temperature data points before plotting.

By default, the tephigram will automatically center the plot around all profiles.

Warning

Pressure data points must be in units of mb or hPa, and temperature data points must be in units of degC.

Args:

data: pressure and temperature pair data points.

Note

All keyword arguments are passed through to matplotlib.pyplot.plot().

For example:
import matplotlib.pyplot as plt
from tephi import Tephigram

tpg = Tephigram()
data = [[1006, 26.4], [924, 20.3], [900, 19.8],
        [850, 14.5], [800, 12.9], [755, 8.3]]
profile = tpg.plot(data, color='red', linestyle='--',
                   linewidth=2, marker='o')
barbs = [(10, 45, 900), (20, 60, 850), (25, 90, 800)]
profile.barbs(barbs)
plt.show()
(Source code, png, hires.png, pdf)

For associating wind barbs with an environmental lapse rate profile, see barbs().