Source code for metpy.plots.station_plot

# Copyright (c) 2016 MetPy Developers.
# Distributed under the terms of the BSD 3-Clause License.
# SPDX-License-Identifier: BSD-3-Clause
"""Create Station-model plots."""

try:
    from enum import Enum
except ImportError:
    from enum34 import Enum

import matplotlib
import numpy as np

from .wx_symbols import (current_weather, high_clouds, low_clouds, mid_clouds,
                         pressure_tendency, sky_cover, wx_symbol_font)
from ..cbook import is_string_like
from ..package_tools import Exporter

exporter = Exporter(globals())


[docs]@exporter.export class StationPlot(object): """Make a standard meteorological station plot. Plots values, symbols, or text spaced around a central location. Can also plot wind barbs as the center of the location. """ location_names = {'C': (0, 0), 'N': (0, 1), 'NE': (1, 1), 'E': (1, 0), 'SE': (1, -1), 'S': (0, -1), 'SW': (-1, -1), 'W': (-1, 0), 'NW': (-1, 1)}
[docs] def __init__(self, ax, x, y, fontsize=10, spacing=None, transform=None, **kwargs): """Initialize the StationPlot with items that do not change. This sets up the axes and station locations. The `fontsize` and `spacing` are also specified here to ensure that they are consistent between individual station elements. Parameters ---------- ax : matplotlib.axes.Axes The :class:`~matplotlib.axes.Axes` for plotting x : array_like The x location of the stations in the plot y : array_like The y location of the stations in the plot fontsize : int The fontsize to use for drawing text spacing : int The spacing, in points, that corresponds to a single increment between station plot elements. transform : matplotlib.transforms.Transform (or compatible) The default transform to apply to the x and y positions when plotting. kwargs Additional keyword arguments to use for matplotlib's plotting functions. These will be passed to all the plotting methods, and thus need to be valid for all plot types, such as `clip_on`. """ self.ax = ax self.x = x self.y = y self.fontsize = fontsize self.spacing = fontsize if spacing is None else spacing self.transform = transform self.items = {} self.barbs = None self.default_kwargs = kwargs
[docs] def plot_symbol(self, location, codes, symbol_mapper, **kwargs): """At the specified location in the station model plot a set of symbols. This specifies that at the offset `location`, the data in `codes` should be converted to unicode characters (for our :data:`wx_symbol_font`) using `symbol_mapper`, and plotted. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or font properties. If something has already been plotted at this location, it will be replaced. Parameters ---------- location : str or tuple[float, float] The offset (relative to center) to plot this parameter. If str, should be one of 'C', 'N', 'NE', 'E', 'SE', 'S', 'SW', 'W', or 'NW'. Otherwise, should be a tuple specifying the number of increments in the x and y directions; increments are multiplied by `spacing` to give offsets in x and y relative to the center. codes : array_like The numeric values that should be converted to unicode characters for plotting. symbol_mapper : callable Controls converting data values to unicode code points for the :data:`wx_symbol_font` font. This should take a value and return a single unicode character. See :mod:`metpy.plots.wx_symbols` for included mappers. kwargs Additional keyword arguments to use for matplotlib's plotting functions. .. plot:: import matplotlib.pyplot as plt import numpy as np from math import ceil from metpy.plots import StationPlot from metpy.plots.wx_symbols import current_weather, current_weather_auto from metpy.plots.wx_symbols import low_clouds, mid_clouds, high_clouds from metpy.plots.wx_symbols import sky_cover, pressure_tendency def plot_symbols(mapper, name, nwrap=12, figsize=(10, 1.4)): # Determine how many symbols there are and layout in rows of nwrap # if there are more than nwrap symbols num_symbols = len(mapper) codes = np.arange(len(mapper)) ncols = nwrap if num_symbols <= nwrap: nrows = 1 x = np.linspace(0, 1, len(mapper)) y = np.ones_like(x) ax_height = 0.8 else: nrows = int(ceil(num_symbols / ncols)) x = np.tile(np.linspace(0, 1, ncols), nrows)[:num_symbols] y = np.repeat(np.arange(nrows, 0, -1), ncols)[:num_symbols] figsize = (10, 1 * nrows + 0.4) ax_height = 0.8 + 0.018 * nrows fig = plt.figure(figsize=figsize, dpi=300) ax = fig.add_axes([0, 0, 1, ax_height]) ax.set_title(name, size=20) ax.xaxis.set_ticks([]) ax.yaxis.set_ticks([]) ax.set_frame_on(False) # Plot sp = StationPlot(ax, x, y, fontsize=36) sp.plot_symbol('C', codes, mapper) sp.plot_parameter((0, -1), codes, fontsize=18) ax.set_ylim(-0.05, nrows + 0.5) plt.show() plot_symbols(current_weather, "Current Weather Symbols") plot_symbols(current_weather_auto, "Current Weather Auto Reported Symbols") plot_symbols(low_clouds, "Low Cloud Symbols") plot_symbols(mid_clouds, "Mid Cloud Symbols") plot_symbols(high_clouds, "High Cloud Symbols") plot_symbols(sky_cover, "Sky Cover Symbols") plot_symbols(pressure_tendency, "Pressure Tendency Symbols") See Also -------- plot_barb, plot_parameter, plot_text """ # Make sure we use our font for symbols kwargs['fontproperties'] = wx_symbol_font.copy() return self.plot_parameter(location, codes, symbol_mapper, **kwargs)
[docs] def plot_parameter(self, location, parameter, formatter='.0f', **kwargs): """At the specified location in the station model plot a set of values. This specifies that at the offset `location`, the data in `parameter` should be plotted. The conversion of the data values to a string is controlled by `formatter`. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or font properties. If something has already been plotted at this location, it will be replaced. Parameters ---------- location : str or tuple[float, float] The offset (relative to center) to plot this parameter. If str, should be one of 'C', 'N', 'NE', 'E', 'SE', 'S', 'SW', 'W', or 'NW'. Otherwise, should be a tuple specifying the number of increments in the x and y directions; increments are multiplied by `spacing` to give offsets in x and y relative to the center. parameter : array_like The numeric values that should be plotted formatter : str or callable, optional How to format the data as a string for plotting. If a string, it should be compatible with the :func:`format` builtin. If a callable, this should take a value and return a string. Defaults to '0.f'. kwargs Additional keyword arguments to use for matplotlib's plotting functions. See Also -------- plot_barb, plot_symbol, plot_text """ text = self._to_string_list(parameter, formatter) return self.plot_text(location, text, **kwargs)
[docs] def plot_text(self, location, text, **kwargs): """At the specified location in the station model plot a collection of text. This specifies that at the offset `location`, the strings in `text` should be plotted. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or font properties. If something has already been plotted at this location, it will be replaced. Parameters ---------- location : str or tuple[float, float] The offset (relative to center) to plot this parameter. If str, should be one of 'C', 'N', 'NE', 'E', 'SE', 'S', 'SW', 'W', or 'NW'. Otherwise, should be a tuple specifying the number of increments in the x and y directions; increments are multiplied by `spacing` to give offsets in x and y relative to the center. text : list (or array) of strings The strings that should be plotted kwargs Additional keyword arguments to use for matplotlib's plotting functions. See Also -------- plot_barb, plot_parameter, plot_symbol """ location = self._handle_location(location) kwargs = self._make_kwargs(kwargs) text_collection = self.ax.scattertext(self.x, self.y, text, loc=location, size=kwargs.pop('fontsize', self.fontsize), **kwargs) if location in self.items: self.items[location].remove() self.items[location] = text_collection return text_collection
[docs] def plot_barb(self, u, v, **kwargs): r"""At the center of the station model plot wind barbs. Additional keyword arguments given will be passed onto matplotlib's :meth:`~matplotlib.axes.Axes.barbs` function; this is useful for specifying things like color or line width. Parameters ---------- u : array-like The data to use for the u-component of the barbs. v : array-like The data to use for the v-component of the barbs. plot_units: `pint.unit` Units to plot in (performing conversion if necessary). Defaults to given units. kwargs Additional keyword arguments to pass to matplotlib's :meth:`~matplotlib.axes.Axes.barbs` function. See Also -------- plot_parameter, plot_symbol, plot_text """ kwargs = self._make_kwargs(kwargs) # If plot_units specified, convert the data to those units plotting_units = kwargs.pop('plot_units', None) if plotting_units: if hasattr(u, 'units') and hasattr(v, 'units'): u = u.to(plotting_units) v = v.to(plotting_units) else: raise ValueError('To convert to plotting units, units must be attached to ' 'u and v wind components.') # Strip units, CartoPy transform doesn't like u = np.array(u) v = np.array(v) # Empirically determined pivot = 0.51 * np.sqrt(self.fontsize) length = 1.95 * np.sqrt(self.fontsize) defaults = {'sizes': {'spacing': .15, 'height': 0.5, 'emptybarb': 0.35}, 'length': length, 'pivot': pivot} defaults.update(kwargs) # Remove old barbs if self.barbs: self.barbs.remove() # Handle transforming our center points. CartoPy doesn't like 1D barbs # TODO: This can be removed for cartopy > 0.14.3 if hasattr(self.ax, 'projection') and 'transform' in kwargs: trans = kwargs['transform'] try: kwargs['transform'] = trans._as_mpl_transform(self.ax) except AttributeError: pass u, v = self.ax.projection.transform_vectors(trans, self.x, self.y, u, v) # Since we've re-implemented CartoPy's barbs, we need to skip calling it here self.barbs = matplotlib.axes.Axes.barbs(self.ax, self.x, self.y, u, v, **defaults) else: self.barbs = self.ax.barbs(self.x, self.y, u, v, **defaults)
def _make_kwargs(self, kwargs): """Assemble kwargs as necessary. Inserts our defaults as well as ensures transform is present when appropriate. """ # Use default kwargs and update with additional ones all_kw = self.default_kwargs.copy() all_kw.update(kwargs) # Pass transform if necessary if 'transform' not in all_kw and self.transform: all_kw['transform'] = self.transform return all_kw @staticmethod def _to_string_list(vals, fmt): """Convert a sequence of values to a list of strings.""" if not callable(fmt): def formatter(s): """Turn a format string into a callable.""" if hasattr(s, 'units'): s = np.asscalar(s) return format(s, fmt) else: formatter = fmt return [formatter(v) if np.isfinite(v) else '' for v in vals] def _handle_location(self, location): """Process locations to get a consistent set of tuples for location.""" if is_string_like(location): location = self.location_names[location] xoff, yoff = location return xoff * self.spacing, yoff * self.spacing
[docs]@exporter.export class StationPlotLayout(dict): r"""make a layout to encapsulate plotting using :class:`StationPlot`. This class keeps a collection of offsets, plot formats, etc. for a parameter based on its name. This then allows a dictionary of data (or any object that allows looking up of arrays based on a name) to be passed to :meth:`plot()` to plot the data all at once. See Also -------- StationPlot """ class PlotTypes(Enum): r"""Different plotting types for the layout. Controls how items are displayed (e.g. converting values to symbols). """ value = 1 symbol = 2 text = 3 barb = 4
[docs] def add_value(self, location, name, fmt='.0f', units=None, **kwargs): r"""Add a numeric value to the station layout. This specifies that at the offset `location`, data should be pulled from the data container using the key `name` and plotted. The conversion of the data values to a string is controlled by `fmt`. The units required for plotting can also be passed in using `units`, which will cause the data to be converted before plotting. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or font properties. Parameters ---------- location : str or tuple[float, float] The offset (relative to center) to plot this value. If str, should be one of 'C', 'N', 'NE', 'E', 'SE', 'S', 'SW', 'W', or 'NW'. Otherwise, should be a tuple specifying the number of increments in the x and y directions. name : str The name of the parameter, which is used as a key to pull data out of the data container passed to :meth:`plot`. fmt : str or callable, optional How to format the data as a string for plotting. If a string, it should be compatible with the :func:`format` builtin. If a callable, this should take a value and return a string. Defaults to '0.f'. units : pint-compatible unit, optional The units to use for plotting. Data will be converted to this unit before conversion to a string. If not specified, no conversion is done. kwargs Additional keyword arguments to use for matplotlib's plotting functions. See Also -------- add_barb, add_symbol, add_text """ self[location] = (self.PlotTypes.value, name, (fmt, units, kwargs))
[docs] def add_symbol(self, location, name, symbol_mapper, **kwargs): r"""Add a symbol to the station layout. This specifies that at the offset `location`, data should be pulled from the data container using the key `name` and plotted. Data values will converted to glyphs appropriate for MetPy's symbol font using the callable `symbol_mapper`. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or font properties. Parameters ---------- location : str or tuple[float, float] The offset (relative to center) to plot this value. If str, should be one of 'C', 'N', 'NE', 'E', 'SE', 'S', 'SW', 'W', or 'NW'. Otherwise, should be a tuple specifying the number of increments in the x and y directions. name : str The name of the parameter, which is used as a key to pull data out of the data container passed to :meth:`plot`. symbol_mapper : callable Controls converting data values to unicode code points for the :data:`wx_symbol_font` font. This should take a value and return a single unicode character. See :mod:`metpy.plots.wx_symbols` for included mappers. kwargs Additional keyword arguments to use for matplotlib's plotting functions. See Also -------- add_barb, add_text, add_value """ self[location] = (self.PlotTypes.symbol, name, (symbol_mapper, kwargs))
[docs] def add_text(self, location, name, **kwargs): r"""Add a text field to the station layout. This specifies that at the offset `location`, data should be pulled from the data container using the key `name` and plotted directly as text with no conversion applied. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or font properties. Parameters ---------- location : str or tuple(float, float) The offset (relative to center) to plot this value. If str, should be one of 'C', 'N', 'NE', 'E', 'SE', 'S', 'SW', 'W', or 'NW'. Otherwise, should be a tuple specifying the number of increments in the x and y directions. name : str The name of the parameter, which is used as a key to pull data out of the data container passed to :meth:`plot`. kwargs Additional keyword arguments to use for matplotlib's plotting functions. See Also -------- add_barb, add_symbol, add_value """ self[location] = (self.PlotTypes.text, name, kwargs)
[docs] def add_barb(self, u_name, v_name, units=None, **kwargs): r"""Add a wind barb to the center of the station layout. This specifies that u- and v-component data should be pulled from the data container using the keys `u_name` and `v_name`, respectively, and plotted as a wind barb at the center of the station plot. If `units` are given, both components will be converted to these units. Additional keyword arguments given will be passed onto the actual plotting code; this is useful for specifying things like color or line width. Parameters ---------- u_name : str The name of the parameter for the u-component for `barbs`, which is used as a key to pull data out of the data container passed to :meth:`plot`. v_name : str The name of the parameter for the v-component for `barbs`, which is used as a key to pull data out of the data container passed to :meth:`plot`. units : pint-compatible unit, optional The units to use for plotting. Data will be converted to this unit before conversion to a string. If not specified, no conversion is done. kwargs Additional keyword arguments to use for matplotlib's :meth:`~matplotlib.axes.Axes.barbs` function. See Also -------- add_symbol, add_text, add_value """ # Not sure if putting the v_name as a plot-specific option is appropriate, # but it seems simpler than making name code in plot handle tuples self['barb'] = (self.PlotTypes.barb, (u_name, v_name), (units, kwargs))
[docs] def names(self): """Get the list of names used by the layout. Returns ------- list[str] the list of names of variables used by the layout """ ret = [] for item in self.values(): if item[0] == self.PlotTypes.barb: ret.extend(item[1]) else: ret.append(item[1]) return ret
[docs] def plot(self, plotter, data_dict): """Plot a collection of data using this layout for a station plot. This function iterates through the entire specified layout, pulling the fields named in the layout from `data_dict` and plotting them using `plotter` as specified in the layout. Fields present in the layout, but not in `data_dict`, are ignored. Parameters ---------- plotter : StationPlot :class:`StationPlot` to use to plot the data. This controls the axes, spacing, station locations, etc. data_dict : dict[str, array-like] Data container that maps a name to an array of data. Data from this object will be used to fill out the station plot. """ def coerce_data(dat, u): try: return dat.to(u).magnitude except AttributeError: return dat for loc, info in self.items(): typ, name, args = info if typ == self.PlotTypes.barb: # Try getting the data u_name, v_name = name u_data = data_dict.get(u_name) v_data = data_dict.get(v_name) # Plot if we have the data if not (v_data is None or u_data is None): units, kwargs = args plotter.plot_barb(coerce_data(u_data, units), coerce_data(v_data, units), **kwargs) else: # Check that we have the data for this location data = data_dict.get(name) if data is not None: # If we have it, hand it to the appropriate method if typ == self.PlotTypes.value: fmt, units, kwargs = args plotter.plot_parameter(loc, coerce_data(data, units), fmt, **kwargs) elif typ == self.PlotTypes.symbol: mapper, kwargs = args plotter.plot_symbol(loc, data, mapper, **kwargs) elif typ == self.PlotTypes.text: plotter.plot_text(loc, data, **args)
def __repr__(self): """Return string representation of layout.""" return ('{' + ', '.join('{0}: ({1[0].name}, {1[1]}, ...)'.format(loc, info) for loc, info in sorted(self.items())) + '}')
with exporter: #: :desc: Simple station plot layout simple_layout = StationPlotLayout() simple_layout.add_barb('eastward_wind', 'northward_wind', 'knots') simple_layout.add_value('NW', 'air_temperature', units='degC') simple_layout.add_value('SW', 'dew_point_temperature', units='degC') simple_layout.add_value('NE', 'air_pressure_at_sea_level', units='mbar', fmt=lambda v: format(10 * v, '03.0f')[-3:]) simple_layout.add_symbol('C', 'cloud_coverage', sky_cover) simple_layout.add_symbol('W', 'present_weather', current_weather) #: Full NWS station plot `layout`__ #: #: __ http://oceanservice.noaa.gov/education/yos/resource/JetStream/synoptic/wxmaps.htm nws_layout = StationPlotLayout() nws_layout.add_value((-1, 1), 'air_temperature', units='degF') nws_layout.add_symbol((0, 2), 'high_cloud_type', high_clouds) nws_layout.add_symbol((0, 1), 'medium_cloud_type', mid_clouds) nws_layout.add_symbol((0, -1), 'low_cloud_type', low_clouds) nws_layout.add_value((1, 1), 'air_pressure_at_sea_level', units='mbar', fmt=lambda v: format(10 * v, '03.0f')[-3:]) nws_layout.add_value((-2, 0), 'visibility_in_air', fmt='.0f', units='miles') nws_layout.add_symbol((-1, 0), 'present_weather', current_weather) nws_layout.add_symbol((0, 0), 'cloud_coverage', sky_cover) nws_layout.add_value((1, 0), 'tendency_of_air_pressure', units='mbar', fmt=lambda v: ('-' if v < 0 else '') + format(10 * abs(v), '02.0f')) nws_layout.add_symbol((2, 0), 'tendency_of_air_pressure_symbol', pressure_tendency) nws_layout.add_barb('eastward_wind', 'northward_wind', units='knots') nws_layout.add_value((-1, -1), 'dew_point_temperature', units='degF') # TODO: Fix once we have the past weather symbols converted nws_layout.add_symbol((1, -1), 'past_weather', current_weather)