"""
Class for creating plots on a geographic map using a Radar object and Basemap.
"""
import warnings
import numpy as np
try:
from mpl_toolkits.basemap import Basemap
_BASEMAP_AVAILABLE = True
except ImportError:
_BASEMAP_AVAILABLE = False
from ..exceptions import MissingOptionalDependency
from .common import parse_ax_fig, parse_cmap, parse_vmin_vmax
from .radardisplay import RadarDisplay
[docs]class RadarMapDisplayBasemap(RadarDisplay):
"""
A display object for creating plots on a geographic map from data in a
Radar object.
This class is still a work in progress. Some functionality may not work
correctly. Please report any problems to the Py-ART GitHub Issue Tracker.
Parameters
----------
radar : Radar
Radar object to use for creating plots.
shift : (float, float)
Shifts in km to offset the calculated x and y locations.
Attributes
----------
plots : list
List of plots created.
plot_vars : list
List of fields plotted, order matches plot list.
cbs : list
List of colorbars created.
origin : str
'Origin' or 'Radar'.
shift : (float, float)
Shift in meters.
loc : (float, float)
Latitude and Longitude of radar in degrees.
fields : dict
Radar fields.
scan_type : str
Scan type.
ranges : array
Gate ranges in meters.
azimuths : array
Azimuth angle in degrees.
elevations : array
Elevations in degrees.
fixed_angle : array
Scan angle in degrees.
proj : Proj
Object for performing cartographic transformations specific to the
geographic map plotted.
basemap : Basemap
Last plotted basemap, None when no basemap has been plotted.
"""
def __init__(self, radar, shift=(0.0, 0.0)):
"""Initialize the object."""
# check that basemap is available
if not _BASEMAP_AVAILABLE:
raise MissingOptionalDependency(
"Basemap is required to use RadarMapDisplayBasemap but is not "
+ "installed"
)
warnings.warn(
"RadarMapDisplayBasemap is deprecated in favor of "
+ "RadarMapDisplay. Basemap is still optional to use, "
+ "but there will be no support if an error appears.",
DeprecationWarning,
)
# initalize the base class
RadarDisplay.__init__(self, radar, shift=shift)
# additional attributes needed for plotting on a basemap.
self.basemap = None
self._x0 = None # x axis radar location in map coords (meters)
self._y0 = None # y axis radar location in map coords (meters)
return
def _check_basemap(self):
"""Check that basemap is not None, raise ValueError if it is."""
if self.basemap is None:
raise ValueError("no basemap plotted")
[docs] def plot_ppi_map(
self,
field,
sweep=0,
mask_tuple=None,
vmin=None,
vmax=None,
cmap=None,
norm=None,
mask_outside=False,
title=None,
title_flag=True,
colorbar_flag=True,
colorbar_label=None,
colorbar_orient="vertical",
ax=None,
fig=None,
lat_lines=None,
lon_lines=None,
projection="lcc",
area_thresh=10000,
min_lon=None,
max_lon=None,
min_lat=None,
max_lat=None,
width=None,
height=None,
lon_0=None,
lat_0=None,
resolution="h",
shapefile=None,
edges=True,
gatefilter=None,
basemap=None,
filter_transitions=True,
embellish=True,
ticks=None,
ticklabs=None,
raster=False,
alpha=None,
edgecolors="face",
**kwargs
):
"""
Plot a PPI volume sweep onto a geographic map.
Additional arguments are passed to Basemap.
Parameters
----------
field : str
Field to plot.
sweep : int, optional
Sweep number to plot.
Other Parameters
----------------
mask_tuple : (str, float)
Tuple containing the field name and value below which to mask
field prior to plotting, for example to mask all data where
NCP < 0.5 set mask_tuple to ['NCP', 0.5]. None performs no masking.
vmin : float
Luminance minimum value, None for default value.
Parameter is ignored is norm is not None.
vmax : float
Luminance maximum value, None for default value.
Parameter is 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 tilt 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.
colorbar_flag : bool
True to add a colorbar with label to the axis. False leaves off
the colorbar.
ticks : array
Colorbar custom tick label locations.
ticklabs : array
Colorbar custom tick labels.
colorbar_label : str
Colorbar label, None will use a default label generated from the
field information.
colorbar_orient : 'vertical' or 'horizontal'
Colorbar orientation.
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.
lat_lines, lon_lines : array or None
Locations at which to draw latitude and longitude lines.
None will use default values which are resonable for maps of
North America.
projection : str
Map projection supported by basemap. The use of cylindrical
projections (mill, merc, etc) is not recommended as they
exhibit large distortions at high latitudes. Equal area
(aea, laea), conformal (lcc, tmerc, stere) or equidistant
projection (aeqd, cass) work well even at high latitudes.
The cylindrical equidistant projection (cyl) is not supported as
coordinate transformations cannot be performed.
area_thresh : float
Coastline or lake with an area smaller than area_thresh in
km^2 will not be plotted.
min_lat, max_lat, min_lon, max_lon : float
Latitude and longitude ranges for the map projection region in
degrees.
width, height : float
Width and height of map domain in meters.
Only this set of parameters or the previous set of parameters
(min_lat, max_lat, min_lon, max_lon) should be specified.
If neither set is specified then the map domain will be determined
from the extend of the radar gate locations.
lon_0, lat_0 : float
Center of the map domain in degrees. If the default, None is used
the latitude and longitude of the radar will be used.
shapefile : str
Filename for a ESRI shapefile as background (untested).
resolution : 'c', 'l', 'i', 'h', or 'f'.
Resolution of boundary database to use. See Basemap documentation
for details.
gatefilter : GateFilter
GateFilter instance. None will result in no gatefilter mask being
applied to data.
filter_transitions : bool
True to remove rays where the antenna was in transition between
sweeps from the plot. False will include these rays in the plot.
No rays are filtered when the antenna_transition attribute of the
underlying radar is not present.
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.
embellish: bool
True by default. Set to false to supress drawing of coastlines
etc.. Use for speedup when specifying shapefiles.
basemap: Basemap instance
If None, create basemap instance using other keyword info.
If not None, use the user-specifed basemap instance.
raster : bool
False by default. Set to true to render the display as a raster
rather than a vector in call to pcolormesh. Saves time in plotting
high resolution data over large areas. Be sure to set the dpi
of the plot for your application if you save it as a vector format
(i.e., pdf, eps, svg).
alpha : float or None
Set the alpha tranparency of the radar plot. Useful for
overplotting radar over other datasets.
edgecolor : str
Set the behavior of the edges of the pixels, by default
it will color them the same as the pixels (faces).
**kwargs : additional keyword arguments to pass to pcolormesh.
"""
# parse parameters
ax, fig = parse_ax_fig(ax, fig)
vmin, vmax = parse_vmin_vmax(self._radar, field, vmin, vmax)
cmap = parse_cmap(cmap, field)
if lat_lines is None:
lat_lines = np.arange(30, 46, 1)
if lon_lines is None:
lon_lines = np.arange(-110, -75, 1)
if lat_0 is None:
lat_0 = self.loc[0]
if lon_0 is None:
lon_0 = self.loc[1]
# get data for the plot
data = self._get_data(field, sweep, mask_tuple, filter_transitions, gatefilter)
x, y = self._get_x_y(sweep, edges, filter_transitions)
# mask the data where outside the limits
if mask_outside:
data = np.ma.masked_outside(data, vmin, vmax)
# create the basemap if not provided
if type(basemap) != Basemap:
using_corners = None not in [min_lon, min_lat, max_lon, max_lat]
if using_corners:
basemap = Basemap(
llcrnrlon=min_lon,
llcrnrlat=min_lat,
urcrnrlon=max_lon,
urcrnrlat=max_lat,
lat_0=lat_0,
lon_0=lon_0,
projection=projection,
area_thresh=area_thresh,
resolution=resolution,
ax=ax,
**kwargs
)
else: # using width and height
# map domain determined from location of radar gates
if width is None:
width = (x.max() - x.min()) * 1000.0
if height is None:
height = (y.max() - y.min()) * 1000.0
basemap = Basemap(
width=width,
height=height,
lon_0=lon_0,
lat_0=lat_0,
projection=projection,
area_thresh=area_thresh,
resolution=resolution,
ax=ax,
**kwargs
)
# The cylindrical equidistant projection does not support conversions
# from geographic (lon/lat) to map projection (x/y) coordinates and
# therefore cannot be used.
if basemap.projection == "cyl":
raise ValueError("The cylindrical equidistant projection is not supported")
# add embelishments
if embellish is True:
basemap.drawcoastlines(linewidth=1.25)
basemap.drawstates()
basemap.drawparallels(lat_lines, labels=[True, False, False, False])
basemap.drawmeridians(lon_lines, labels=[False, False, False, True])
self.basemap = basemap
self._x0, self._y0 = basemap(self.loc[1], self.loc[0])
# plot the data and optionally the shape file
# we need to convert the radar gate locations (x and y) which are in
# km to meters as well as add the map coordiate radar location
# which is given by self._x0, self._y0.
if norm is not None: # if norm is set do not override with vmin/vmax
vmin = vmax = None
pm = basemap.pcolormesh(
self._x0 + x * 1000.0,
self._y0 + y * 1000.0,
data,
vmin=vmin,
vmax=vmax,
cmap=cmap,
norm=norm,
alpha=alpha,
edgecolors=edgecolors,
**kwargs
)
if raster:
pm.set_rasterized(True)
if shapefile is not None:
basemap.readshapefile(shapefile, "shapefile", ax=ax)
if title_flag:
self._set_title(field, sweep, title, ax)
# add plot and field to lists
self.plots.append(pm)
self.plot_vars.append(field)
if colorbar_flag:
self.plot_colorbar(
mappable=pm,
label=colorbar_label,
orient=colorbar_orient,
field=field,
fig=fig,
ax=ax,
ticks=ticks,
ticklabs=ticklabs,
)
return
[docs] def plot_point(
self,
lon,
lat,
symbol="ro",
label_text=None,
label_offset=(None, None),
**kwargs
):
"""
Plot a point on the current map.
Additional arguments are passed to basemap.plot.
Parameters
----------
lon : float
Longitude of point to plot.
lat : float
Latitude of point to plot.
symbol : str
Matplotlib compatible string which specified the symbol of the
point.
label_text : str, optional.
Text to label symbol with. If None no label will be added.
label_offset : [float, float]
Offset in lon, lat degrees for the bottom left corner of the label
text relative to the point. A value of None will use 0.01 de
"""
self._check_basemap()
lon_offset, lat_offset = label_offset
if lon_offset is None:
lon_offset = 0.01
if lat_offset is None:
lat_offset = 0.01
self.basemap.plot(lon, lat, symbol, latlon=True, **kwargs)
if label_text is not None:
# basemap does not have a text method so we must determine
# the x and y points and plot them on the basemap's axis.
x_text, y_text = self.basemap(lon + lon_offset, lat + lat_offset)
self.basemap.ax.text(x_text, y_text, label_text)
[docs] def plot_line_geo(self, line_lons, line_lats, line_style="r-", **kwargs):
"""
Plot a line segments on the current map given values in lat and lon.
Additional arguments are passed to basemap.plot.
Parameters
----------
line_lons : array
Longitude of line segment to plot.
line_lats : array
Latitude of line segment to plot.
line_style : str
Matplotlib compatible string which specifies the line style.
"""
self._check_basemap()
self.basemap.plot(line_lons, line_lats, line_style, latlon=True, **kwargs)
[docs] def plot_line_xy(self, line_x, line_y, line_style="r-", **kwargs):
"""
Plot a line segments on the current map given radar x, y values.
Additional arguments are passed to basemap.plot.
Parameters
----------
line_x : array
X location of points to plot in meters from the radar.
line_y : array
Y location of points to plot in meters from the radar.
line_style : str, optional
Matplotlib compatible string which specifies the line style.
"""
self._check_basemap()
self.basemap.plot(
self._x0 + line_x, self._y0 + line_y, line_style, latlon=False, **kwargs
)
[docs] def plot_range_ring(
self, range_ring_location_km, npts=360, line_style="k-", **kwargs
):
"""
Plot a single range ring on the map.
Additional arguments are passed to basemap.plot.
Parameters
----------
range_ring_location_km : float
Location of range ring in km.
npts: int
Number of points in the ring, higher for better resolution.
line_style : str
Matplotlib compatible string which specified the line
style of the ring.
"""
# The RadarDisplay.plot_range_rings uses a col parameter to specify
# the line color, deal with this here.
if "col" in kwargs:
color = kwargs.pop("col")
kwargs["c"] = color
self._check_basemap()
angle = np.linspace(0.0, 2.0 * np.pi, npts)
xpts = range_ring_location_km * 1000.0 * np.sin(angle)
ypts = range_ring_location_km * 1000.0 * np.cos(angle)
self.plot_line_xy(xpts, ypts, line_style=line_style, **kwargs)