"""
A class for plotting grid objects with a basemap.
"""
import warnings
import numpy as np
import matplotlib.pyplot as plt
try:
from mpl_toolkits.basemap import Basemap
from mpl_toolkits.basemap import pyproj
_BASEMAP_AVAILABLE = True
except ImportError:
_BASEMAP_AVAILABLE = False
from . import common
from ..exceptions import MissingOptionalDependency
from ..core.transforms import _interpolate_axes_edges
[docs]class GridMapDisplayBasemap(object):
"""
A class for creating plots from a grid object on top of a Basemap.
Parameters
----------
grid : Grid
Grid with data which will be used to create plots.
debug : bool
True to print debugging messages, False to supress them.
Attributes
----------
grid : Grid
Grid object.
debug : bool
True to print debugging messages, False to supressed them.
basemap : Basemap
Last plotted basemap, None when no basemap has been plotted.
mappables : list
List of ContourSet, etc. which have been plotted, useful
when adding colorbars.
fields : list
List of fields which have been plotted.
"""
def __init__(self, grid, debug=False):
""" initalize the object. """
# check that basemap is available
if not _BASEMAP_AVAILABLE:
raise MissingOptionalDependency(
"Basemap is required to use GridMapDisplay but is not " +
"installed")
# set attributes
self.grid = grid
self.debug = debug
self.mappables = []
self.fields = []
self.origin = 'origin'
self.basemap = None
[docs] def plot_basemap(
self, lat_lines=None, lon_lines=None, resolution='l',
area_thresh=10000, auto_range=True, min_lon=-92, max_lon=-86,
min_lat=40, max_lat=44, ax=None, **kwargs):
"""
Plot a basemap.
Parameters
----------
lat_lines, lon_lines : array or None
Locations at which to draw latitude and longitude lines.
None will use default values which are reasonable for maps of
North America.
auto_range : bool
True to determine map ranges from the latitude and longitude
limits of the grid. False will use the min_lon, max_lon, min_lat,
and max_lat parameters for the map range.
min_lat, max_lat, min_lon, max_lon : float
Latitude and longitude ranges for the map projection region in
degrees. These parameter are not used if auto_range is True.
resolution : 'c', 'l', 'i', 'h', or 'f'.
Resolution of boundary database to use. See Basemap documentation
for details.
area_thresh : int
Basemap area_thresh parameter. See Basemap documentation.
ax : axes or None.
Axis to add the basemap to, if None the current axis is used.
kwargs: Basemap options
Options to be passed to Basemap. If projection is not specified
here it uses proj='merc' (mercator).
"""
# make basemap
self._make_basemap(resolution, area_thresh, auto_range,
min_lon, max_lon, min_lat, max_lat, ax, **kwargs)
# parse the parameters
if lat_lines is None:
lat_lines = np.arange(30, 46, 1)
if lon_lines is None:
lon_lines = np.arange(-110, -75, 1)
self.basemap.drawcoastlines(linewidth=1.25)
self.basemap.drawstates()
self.basemap.drawparallels(
lat_lines, labels=[True, False, False, False])
self.basemap.drawmeridians(
lon_lines, labels=[False, False, False, True])
[docs] def plot_grid(
self, field, level=0,
vmin=None, vmax=None, norm=None, cmap=None,
mask_outside=False, title=None, title_flag=True,
axislabels=(None, None), axislabels_flag=False,
colorbar_flag=True, colorbar_label=None,
colorbar_orient='vertical', edges=True,
ax=None, fig=None, ticks=None, ticklabs=None, **kwargs):
"""
Plot the grid onto the current basemap.
Additional arguments are passed to Basemaps's pcolormesh function.
Parameters
----------
field : str
Field to be plotted.
level : int
Index corresponding to the height level to be plotted.
vmin, vmax : float
Lower and upper range for the colormesh. If either parameter is
None, a value will be determined from the field attributes (if
available) or the default values of -8, 64 will be used.
Parameters are ignored is norm is not None.
norm : Normalize or None, optional
matplotlib Normalize instance used to scale luminance data. If not
None the vmax and vmin parameters are ignored. If None, vmin and
vmax are used for luminance scaling.
cmap : str or None
Matplotlib colormap name. None will use the default colormap for
the field being plotted as specified by the Py-ART configuration.
mask_outside : bool
True to mask data outside of vmin, vmax. False performs no
masking.
title : str
Title to label plot with, None to use default title generated from
the field and level parameters. Parameter is ignored if title_flag
is False.
title_flag : bool
True to add a title to the plot, False does not add a title.
axislabels : (str, str)
2-tuple of x-axis, y-axis labels. None for either label will use
the default axis label. Parameter is ignored if axislabels_flag is
False.
axislabels_flag : bool
True to add label the axes, False does not label the axes.
colorbar_flag : bool
True to add a colorbar with label to the axis. False leaves off
the colorbar.
colorbar_label : str
Colorbar label, None will use a default label generated from the
field information.
colorbar_orient : 'vertical' or 'horizontal'
Colorbar orientation.
edges : bool
True will interpolate and extrapolate the gate edges from the
range, azimuth and elevations in the radar, treating these
as specifying the center of each gate. False treats these
coordinates themselved as the gate edges, resulting in a plot
in which the last gate in each ray and the entire last ray are not
not plotted.
ax : Axis
Axis to plot on. None will use the current axis.
fig : Figure
Figure to add the colorbar to. None will use the current figure.
ticks : array
Colorbar custom tick label locations.
ticklabs : array
Colorbar custom tick labels.
"""
# parse parameters
ax, fig = common.parse_ax_fig(ax, fig)
vmin, vmax = common.parse_vmin_vmax(self.grid, field, vmin, vmax)
cmap = common.parse_cmap(cmap, field)
basemap = self.get_basemap()
data = self.grid.fields[field]['data'][level]
# mask the data where outside the limits
if mask_outside:
data = np.ma.masked_invalid(data)
data = np.ma.masked_outside(data, vmin, vmax)
# plot the grid
lons, lats = self.grid.get_point_longitude_latitude(edges=edges)
if norm is not None: # if norm is set do not override with vmin/vmax
vmin = vmax = None
pm = basemap.pcolormesh(
lons, lats, data, vmin=vmin, vmax=vmax, cmap=cmap, norm=norm,
latlon=True, **kwargs)
self.mappables.append(pm)
self.fields.append(field)
if title_flag:
if title is None:
ax.set_title(self.generate_grid_title(field, level))
else:
ax.set_title(title)
if axislabels_flag:
self._label_axes_grid(axislabels, ax)
if colorbar_flag:
self.plot_colorbar(
mappable=pm, label=colorbar_label, orientation=colorbar_orient,
field=field, ax=ax, fig=fig, ticks=ticks, ticklabs=ticklabs)
return
[docs] def plot_crosshairs(
self, lon=None, lat=None, line_style='r--', linewidth=2, ax=None):
"""
Plot crosshairs at a given longitude and latitude.
Parameters
----------
lon, lat : float
Longitude and latitude (in degrees) where the crosshairs should
be placed. If None the center of the grid is used.
line_style : str
Matplotlib string describing the line style.
linewidth : float
Width of markers in points.
ax : axes or None.
Axis to add the crosshairs to, if None the current axis is used.
"""
# parse the parameters
ax = common.parse_ax(ax)
lon, lat = common.parse_lon_lat(self.grid, lon, lat)
basemap = self.get_basemap()
# add crosshairs.
x_lon, y_lon = basemap(
np.array([lon, lon]),
np.array([basemap.latmin, basemap.latmax]))
x_lat, y_lat = basemap(
np.array([basemap.lonmin, basemap.lonmax]),
np.array([lat, lat]))
ax.plot(x_lon, y_lon, line_style, linewidth=linewidth)
ax.plot(x_lat, y_lat, line_style, linewidth=linewidth)
return
[docs] def plot_latitude_slice(self, field, lon=None, lat=None, **kwargs):
"""
Plot a slice along a given latitude.
For documentation of additional arguments see
:py:func:`plot_latitudinal_level`.
Parameters
----------
field : str
Field to be plotted.
lon, lat : float
Longitude and latitude (in degrees) specifying the slice. If
None the center of the grid is used.
"""
# parse parameters
_, y_index = self._find_nearest_grid_indices(lon, lat)
self.plot_latitudinal_level(field=field, y_index=y_index, **kwargs)
[docs] def plot_latitudinal_level(
self, field, y_index,
vmin=None, vmax=None, norm=None, cmap=None,
mask_outside=False, title=None, title_flag=True,
axislabels=(None, None), axislabels_flag=True, colorbar_flag=True,
colorbar_label=None, colorbar_orient='vertical', edges=True,
ax=None, fig=None, ticks=None, ticklabs=None, **kwargs):
"""
Plot a slice along a given latitude.
Additional arguments are passed to Basemaps's pcolormesh function.
Parameters
----------
field : str
Field to be plotted.
y_index : float
Index of the latitudinal level to plot.
vmin, vmax : float
Lower and upper range for the colormesh. If either parameter is
None, a value will be determined from the field attributes (if
available) or the default values of -8, 64 will be used.
Parameters are ignored is norm is not None.
norm : Normalize or None, optional
matplotlib Normalize instance used to scale luminance data. If not
None the vmax and vmin parameters are ignored. If None, vmin and
vmax are used for luminance scaling.
cmap : str or None
Matplotlib colormap name. None will use the default colormap for
the field being plotted as specified by the Py-ART configuration.
mask_outside : bool
True to mask data outside of vmin, vmax. False performs no
masking.
title : str
Title to label plot with, None to use default title generated from
the field and lat,lon parameters. Parameter is ignored if
title_flag is False.
title_flag : bool
True to add a title to the plot, False does not add a title.
axislabels : (str, str)
2-tuple of x-axis, y-axis labels. None for either label will use
the default axis label. Parameter is ignored if axislabels_flag is
False.
axislabels_flag : bool
True to add label the axes, False does not label the axes.
colorbar_flag : bool
True to add a colorbar with label to the axis. False leaves off
the colorbar.
colorbar_label : str
Colorbar label, None will use a default label generated from the
field information.
colorbar_orient : 'vertical' or 'horizontal'
Colorbar orientation.
edges : bool
True will interpolate and extrapolate the gate edges from the
range, azimuth and elevations in the radar, treating these
as specifying the center of each gate. False treats these
coordinates themselved as the gate edges, resulting in a plot
in which the last gate in each ray and the entire last ray are not
not plotted.
ax : Axis
Axis to plot on. None will use the current axis.
fig : Figure
Figure to add the colorbar to. None will use the current figure.
ticks : array
Colorbar custom tick label locations.
ticklabs : array
Colorbar custom tick labels.
"""
# parse parameters
ax, fig = common.parse_ax_fig(ax, fig)
vmin, vmax = common.parse_vmin_vmax(self.grid, field, vmin, vmax)
cmap = common.parse_cmap(cmap, field)
data = self.grid.fields[field]['data'][:, y_index, :]
# mask the data where outside the limits
if mask_outside:
data = np.ma.masked_invalid(data)
data = np.ma.masked_outside(data, vmin, vmax)
# plot the grid
x_1d = self.grid.x['data'] / 1000.
z_1d = self.grid.z['data'] / 1000.
if edges:
if len(x_1d) > 1:
x_1d = _interpolate_axes_edges(x_1d)
if len(z_1d) > 1:
z_1d = _interpolate_axes_edges(z_1d)
xd, yd = np.meshgrid(x_1d, z_1d)
if norm is not None: # if norm is set do not override with vmin/vmax
vmin = vmax = None
pm = ax.pcolormesh(
xd, yd, data, vmin=vmin, vmax=vmax, norm=norm, cmap=cmap, **kwargs)
self.mappables.append(pm)
self.fields.append(field)
if title_flag:
if title is None:
ax.set_title(common.generate_latitudinal_level_title(
self.grid, field, y_index))
else:
ax.set_title(title)
if axislabels_flag:
self._label_axes_latitude(axislabels, ax)
if colorbar_flag:
self.plot_colorbar(
mappable=pm, label=colorbar_label, orientation=colorbar_orient,
field=field, ax=ax, fig=fig, ticks=ticks, ticklabs=ticklabs)
return
[docs] def plot_longitude_slice(self, field, lon=None, lat=None, **kwargs):
"""
Plot a slice along a given longitude.
For documentation of additional arguments see
:py:func:`plot_longitudinal_level`.
Parameters
----------
field : str
Field to be plotted.
lon, lat : float
Longitude and latitude (in degrees) specifying the slice. If
None the center of the grid is used.
"""
x_index, _ = self._find_nearest_grid_indices(lon, lat)
self.plot_longitudinal_level(field=field, x_index=x_index, **kwargs)
[docs] def plot_longitudinal_level(
self, field, x_index,
vmin=None, vmax=None, norm=None, cmap=None,
mask_outside=False, title=None, title_flag=True,
axislabels=(None, None), axislabels_flag=True, colorbar_flag=True,
colorbar_label=None, colorbar_orient='vertical', edges=True,
ax=None, fig=None, ticks=None, ticklabs=None, **kwargs):
"""
Plot a slice along a given longitude.
Additional arguments are passed to Basemaps's pcolormesh function.
Parameters
----------
field : str
Field to be plotted.
x_index : float
Index of the longitudinal level to plot.
vmin, vmax : float
Lower and upper range for the colormesh. If either parameter is
None, a value will be determined from the field attributes (if
available) or the default values of -8, 64 will be used.
Parameters are ignored is norm is not None.
norm : Normalize or None, optional
matplotlib Normalize instance used to scale luminance data. If not
None the vmax and vmin parameters are ignored. If None, vmin and
vmax are used for luminance scaling.
cmap : str or None
Matplotlib colormap name. None will use the default colormap for
the field being plotted as specified by the Py-ART configuration.
mask_outside : bool
True to mask data outside of vmin, vmax. False performs no
masking.
title : str
Title to label plot with, None to use default title generated from
the field and lat,lon parameters. Parameter is ignored if
title_flag is False.
title_flag : bool
True to add a title to the plot, False does not add a title.
axislabels : (str, str)
2-tuple of x-axis, y-axis labels. None for either label will use
the default axis label. Parameter is ignored if axislabels_flag is
False.
axislabels_flag : bool
True to add label the axes, False does not label the axes.
colorbar_flag : bool
True to add a colorbar with label to the axis. False leaves off
the colorbar.
colorbar_label : str
Colorbar label, None will use a default label generated from the
field information.
colorbar_orient : 'vertical' or 'horizontal'
Colorbar orientation.
edges : bool
True will interpolate and extrapolate the gate edges from the
range, azimuth and elevations in the radar, treating these
as specifying the center of each gate. False treats these
coordinates themselved as the gate edges, resulting in a plot
in which the last gate in each ray and the entire last ray are not
not plotted.
ax : Axis
Axis to plot on. None will use the current axis.
fig : Figure
Figure to add the colorbar to. None will use the current figure.
ticks : array
Colorbar custom tick label locations.
ticklabs : array
Colorbar custom tick labels.
"""
# parse parameters
ax, fig = common.parse_ax_fig(ax, fig)
vmin, vmax = common.parse_vmin_vmax(self.grid, field, vmin, vmax)
cmap = common.parse_cmap(cmap, field)
data = self.grid.fields[field]['data'][:, :, x_index]
# mask the data where outside the limits
if mask_outside:
data = np.ma.masked_invalid(data)
data = np.ma.masked_outside(data, vmin, vmax)
# plot the grid
y_1d = self.grid.y['data'] / 1000.
z_1d = self.grid.z['data'] / 1000.
if edges:
if len(y_1d) > 1:
y_1d = _interpolate_axes_edges(y_1d)
if len(z_1d) > 1:
z_1d = _interpolate_axes_edges(z_1d)
xd, yd = np.meshgrid(y_1d, z_1d)
if norm is not None: # if norm is set do not override with vmin/vmax
vmin = vmax = None
pm = ax.pcolormesh(
xd, yd, data, vmin=vmin, vmax=vmax, cmap=cmap, norm=norm, **kwargs)
self.mappables.append(pm)
self.fields.append(field)
if title_flag:
if title is None:
ax.set_title(common.generate_longitudinal_level_title(
self.grid, field, x_index))
else:
ax.set_title(title)
if axislabels_flag:
self._label_axes_longitude(axislabels, ax)
if colorbar_flag:
self.plot_colorbar(
mappable=pm, label=colorbar_label, orientation=colorbar_orient,
field=field, ax=ax, fig=fig, ticks=ticks, ticklabs=ticklabs)
return
[docs] def plot_colorbar(
self, mappable=None, orientation='horizontal', label=None,
cax=None, ax=None, fig=None, field=None, ticks=None,
ticklabs=None):
"""
Plot a colorbar.
Parameters
----------
mappable : Image, ContourSet, etc.
Image, ContourSet, etc to which the colorbar applied. If None the
last mappable object will be used.
field : str
Field to label colorbar with.
label : str
Colorbar label. None will use a default value from the last field
plotted.
orient : str
Colorbar orientation, either 'vertical' [default] or 'horizontal'.
cax : Axis
Axis onto which the colorbar will be drawn. None is also valid.
ax : Axes
Axis onto which the colorbar will be drawn. None is also valid.
fig : Figure
Figure to place colorbar on. None will use the current figure.
ticks : array
Colorbar custom tick label locations.
ticklabs : array
Colorbar custom tick labels.
"""
if fig is None:
fig = plt.gcf()
if mappable is None:
if len(self.mappables) == 0:
raise ValueError('mappable must be specified.')
else:
mappable = self.mappables[-1]
if label is None:
if len(self.fields) == 0:
raise ValueError('field must be specified.')
field = self.grid.fields[self.fields[-1]]
if 'long_name' in field and 'units' in field:
label = field['long_name'] + '(' + field['units'] + ')'
else:
label = ''
# plot the colorbar and set the label.
cb = fig.colorbar(mappable, orientation=orientation, ax=ax, cax=cax)
if ticks is not None:
cb.set_ticks(ticks)
if ticklabs is not None:
cb.set_ticklabels(ticklabs)
cb.set_label(label)
return
def _make_basemap(
self, resolution='l', area_thresh=10000, auto_range=True,
min_lon=-92, max_lon=-86, min_lat=40, max_lat=44, ax=None,
**kwargs):
"""
Make a basemap.
Parameters
----------
auto_range : bool
True to determine map ranges from the latitude and longitude limits
of the grid. False will use the min_lon, max_lon, min_lat, and
max_lat parameters for the map range.
min_lat, max_lat, min_lon, max_lon : float
Latitude and longitude ranges for the map projection region in
degrees. These parameter are not used if auto_range is True.
resolution : 'c', 'l', 'i', 'h', or 'f'.
Resolution of boundary database to use. See Basemap documentation
for details.
area_thresh : int
Basemap area_thresh parameter. See Basemap documentation.
ax : axes or None.
Axis to add the basemap to, if None the current axis is used.
kwargs : Basemap options
Options to be passed to Basemap. If projection is not specified
here it uses proj='merc' (mercator).
"""
# parse the parameters
ax = common.parse_ax(ax)
# determine map region
if auto_range:
max_lat = self.grid.point_latitude['data'][0].max()
max_lon = self.grid.point_longitude['data'][0].max()
min_lat = self.grid.point_latitude['data'][0].min()
min_lon = self.grid.point_longitude['data'][0].min()
if self.debug:
print("Maximum latitude: ", max_lat)
print("Maximum longitude: ", max_lon)
print("Minimum latitude: ", min_lat)
print("Minimum longitute: ", min_lon)
# determine plot center
lat_0 = self.grid.origin_latitude['data'][0]
lon_0 = self.grid.origin_longitude['data'][0]
default_args = {
'lat_0': lat_0, 'lon_0': lon_0, 'lat_ts': lat_0,
'projection': 'merc', 'area_thresh': area_thresh,
'resolution': resolution, 'ax': ax}
using_corners = (None not in [min_lon, min_lat, max_lon, max_lat])
if using_corners:
default_args['llcrnrlon'] = min_lon
default_args['llcrnrlat'] = min_lat
default_args['urcrnrlon'] = max_lon
default_args['urcrnrlat'] = max_lat
else:
# determine width and height of the plot
x = self.grid.x['data'][0]
y = self.grid.y['data'][0]
default_args['width'] = (x.max() - x.min())
default_args['height'] = (y.max() - y.min())
for key in default_args.keys():
if key not in kwargs:
kwargs[key] = default_args[key]
# plot the basemap
self.basemap = Basemap(**kwargs)
return self.basemap
def _find_nearest_grid_indices(self, lon, lat):
"""
Find the nearest x, y grid indices for a given latitude and longitude.
"""
# A similar method would make a good addition to the Grid class itself
lon, lat = common.parse_lon_lat(self.grid, lon, lat)
grid_lons, grid_lats = self.grid.get_point_longitude_latitude()
diff = (grid_lats - lat)**2 + (grid_lons - lon)**2
y_index, x_index = np.unravel_index(diff.argmin(), diff.shape)
return x_index, y_index
##########################
# Plot adjusting methods #
##########################
def _get_label_x(self):
""" Get default label for x units. """
return 'East West distance from ' + self.origin + ' (km)'
def _get_label_y(self):
""" Get default label for y units. """
return 'North South distance from ' + self.origin + ' (km)'
def _get_label_z(self):
""" Get default label for z units. """
return 'Distance Above ' + self.origin + ' (km)'
def _label_axes_grid(self, axis_labels, ax):
""" Set the x and y axis labels for a grid plot. """
x_label, y_label = axis_labels
if x_label is None:
x_label = self._get_label_x()
if y_label is None:
y_label = self._get_label_y()
ax.set_xlabel(x_label)
ax.set_ylabel(y_label)
def _label_axes_longitude(self, axis_labels, ax):
""" Set the x and y axis labels for a longitude slice. """
x_label, y_label = axis_labels
if x_label is None:
x_label = self._get_label_y()
if y_label is None:
y_label = self._get_label_z()
ax.set_xlabel(x_label)
ax.set_ylabel(y_label)
def _label_axes_latitude(self, axis_labels, ax):
""" Set the x and y axis labels for a latitude slice. """
x_label, y_label = axis_labels
if x_label is None:
x_label = self._get_label_x()
if y_label is None:
y_label = self._get_label_z()
ax.set_xlabel(x_label)
ax.set_ylabel(y_label)
##########################
# name generator methods #
##########################
[docs] def generate_filename(self, field, level, ext='png'):
"""
Generate a filename for a grid plot.
Generated filename has form:
grid_name_field_level_time.ext
Parameters
----------
field : str
Field plotted.
level : int
Level plotted.
ext : str
Filename extension.
Returns
-------
filename : str
Filename suitable for saving a plot.
"""
return common.generate_grid_filename(self.grid, field, level, ext)
[docs] def generate_grid_title(self, field, level):
"""
Generate a title for a plot.
Parameters
----------
field : str
Field plotted.
level : int
Verical level plotted.
Returns
-------
title : str
Plot title.
"""
return common.generate_grid_title(self.grid, field, level)
[docs] def generate_longitudinal_level_title(self, field, level):
"""
Generate a title for a plot.
Parameters
----------
field : str
Field plotted.
level : int
Longitudinal level plotted.
Returns
-------
title : str
Plot title.
"""
return common.generate_longitudinal_level_title(
self.grid, field, level)
[docs] def generate_latitudinal_level_title(self, field, level):
"""
Generate a title for a plot.
Parameters
----------
field : str
Field plotted.
level : int
Longitudinal level plotted.
Returns
-------
title : str
Plot title.
"""
return common.generate_latitudinal_level_title(
self.grid, field, level)
##########################
# get methods #
##########################
[docs] def get_basemap(self):
""" get basemap of the plot """
if self.basemap is None:
self._make_basemap()
return self.basemap