Source code for pyart.graph.radarmapdisplay_basemap

Class for creating plots on a geographic map using a Radar object and Basemap.


import warnings

import numpy as np
    from mpl_toolkits.basemap import Basemap
except ImportError:

from .radardisplay import RadarDisplay
from .common import parse_ax_fig, parse_vmin_vmax, parse_cmap
from ..exceptions import MissingOptionalDependency

[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, 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, embelish=True, ticks=None, ticklabs=None, raster=False, alpha=None, **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. 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. embelish: 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. """ # 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 =, 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. if height is None: height = (y.max() - y.min()) * 1000. 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 embelish 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., self._y0 + y * 1000., data, vmin=vmin, vmax=vmax, cmap=cmap, norm=norm, alpha=alpha) 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, 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), 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., 2.0 * np.pi, npts) xpts = range_ring_location_km * 1000. * np.sin(angle) ypts = range_ring_location_km * 1000. * np.cos(angle) self.plot_line_xy(xpts, ypts, line_style=line_style, **kwargs)