add mpl_args and stroke_width

src/metpy/plots/declarative.py

@@ -56,13 +56,14 @@ def lookup_map_feature(feature_name):
     return feat.with_scale(scaler)
 
 
-def plot_kwargs(data):
+def plot_kwargs(data, args):
     """Set the keyword arguments for MapPanel plotting."""
     if hasattr(data.metpy, 'cartopy_crs'):
         # Conditionally add cartopy transform if we are on a map.
         kwargs = {'transform': data.metpy.cartopy_crs}
     else:
         kwargs = {}
+    kwargs.update(args)
     return kwargs
 
 
@@ -102,8 +103,17 @@ def __dir__(self):
             lambda name: not (name in dir(HasTraits) or name.startswith('_')),
             dir(type(self))
         )
-
-    mpl_args = Union([Dict(), Int(), Float(), Unicode()])
+
+    mpl_args = Dict(allow_none=True)
+    mpl_args.__doc__ = """Supply a dictionary of valid Matplotlib keyword arguments to modify
+    how the plot variable is drawn.
+
+    Using this attribute you must choose the appropriate keyword arguments (kwargs) based on
+    what you are plotting (e.g., contours, color-filled contours, image plot, etc.). This is
+    available for all plot types (ContourPlot, FilledContourPlot, RasterPlot, ImagePlot,
+    BarbPlot, ArrowPlot, PlotGeometry, and PlotObs). Note that for the PlotObs, the kwargs
+    are those to specify the StationPlot object.
+    """
 
 
 class Panel(MetPyHasTraits):
@@ -938,20 +948,17 @@ def _build(self):
         """Build the plot by calling any plotting methods as necessary."""
         x_like, y_like, imdata = self.plotdata
 
-        kwargs = plot_kwargs(imdata)
+        kwargs = plot_kwargs(imdata, self.mpl_args)
 
         # If we're on a map, we use min/max for y and manually figure out origin to try to
         # avoid upside down images created by images where y[0] > y[-1], as well as
         # specifying the transform
         kwargs['extent'] = (x_like[0], x_like[-1], y_like.min(), y_like.max())
         kwargs['origin'] = 'upper' if y_like[0] > y_like[-1] else 'lower'
+        kwargs.setdefault('cmap', self._cmap_obj)
+        kwargs.setdefault('norm', self._norm_obj)
 
-        self.handle = self.parent.ax.imshow(
-            imdata,
-            cmap=self._cmap_obj,
-            norm=self._norm_obj,
-            **kwargs
-        )
+        self.handle = self.parent.ax.imshow(imdata, **kwargs)
 
 
 @exporter.export
@@ -995,11 +1002,12 @@ def _build(self):
         """Build the plot by calling any plotting methods as necessary."""
         x_like, y_like, imdata = self.plotdata
 
-        kwargs = plot_kwargs(imdata)
+        kwargs = plot_kwargs(imdata, self.mpl_args)
+        kwargs.setdefault('linewidths', self.linewidth)
+        kwargs.setdefault('colors', self.linecolor)
+        kwargs.setdefault('linestyles', self.linestyle)
 
-        self.handle = self.parent.ax.contour(x_like, y_like, imdata, self.contours,
-                                             colors=self.linecolor, linewidths=self.linewidth,
-                                             linestyles=self.linestyle, **kwargs)
+        self.handle = self.parent.ax.contour(x_like, y_like, imdata, self.contours, **kwargs)
         if self.clabels:
             self.handle.clabel(inline=1, fmt='%.0f', inline_spacing=8,
                                use_clabeltext=True, fontsize=self.label_fontsize)
@@ -1020,11 +1028,11 @@ def _build(self):
         """Build the plot by calling any plotting methods as necessary."""
         x_like, y_like, imdata = self.plotdata
 
-        kwargs = plot_kwargs(imdata)
+        kwargs = plot_kwargs(imdata, self.mpl_args)
+        kwargs.setdefault('cmap', self._cmap_obj)
+        kwargs.setdefault('norm', self._norm_obj)
 
-        self.handle = self.parent.ax.contourf(x_like, y_like, imdata, self.contours,
-                                              cmap=self._cmap_obj, norm=self._norm_obj,
-                                              **kwargs)
+        self.handle = self.parent.ax.contourf(x_like, y_like, imdata, self.contours, **kwargs)
 
 
 @exporter.export
@@ -1042,11 +1050,11 @@ def _build(self):
         """Build the raster plot by calling any plotting methods as necessary."""
         x_like, y_like, imdata = self.plotdata
 
-        kwargs = plot_kwargs(imdata)
+        kwargs = plot_kwargs(imdata, self.mpl_args)
+        kwargs.setdefault('cmap', self._cmap_obj)
+        kwargs.setdefault('norm', self._norm_obj)
 
-        self.handle = self.parent.ax.pcolormesh(x_like, y_like, imdata,
-                                                cmap=self._cmap_obj, norm=self._norm_obj,
-                                                **kwargs)
+        self.handle = self.parent.ax.pcolormesh(x_like, y_like, imdata, **kwargs)
 
 
 @exporter.export
@@ -1221,7 +1229,11 @@ def _build(self):
         """Build the plot by calling needed plotting methods as necessary."""
         x_like, y_like, u, v = self.plotdata
 
-        kwargs = plot_kwargs(u)
+        kwargs = plot_kwargs(u, self.mpl_args)
+        kwargs.setdefault('color', self.color)
+        kwargs.setdefault('pivot', self.pivot)
+        kwargs.setdefault('length', self.barblength)
+        kwargs.setdefault('zorder', 2)
 
         # Conditionally apply the proper transform
         if 'transform' in kwargs and self.earth_relative:
@@ -1232,7 +1244,7 @@ def _build(self):
         self.handle = self.parent.ax.barbs(
             x_like[wind_slice], y_like[wind_slice],
             u.values[wind_slice], v.values[wind_slice],
-            color=self.color, pivot=self.pivot, length=self.barblength, zorder=2, **kwargs)
+            **kwargs)
 
 
 @exporter.export
@@ -1283,7 +1295,10 @@ def _build(self):
         """Build the plot by calling needed plotting methods as necessary."""
         x_like, y_like, u, v = self.plotdata
 
-        kwargs = plot_kwargs(u)
+        kwargs = plot_kwargs(u, self.mpl_args)
+        kwargs.setdefault('color', self.color)
+        kwargs.setdefault('pivot', self.pivot)
+        kwargs.setdefault('scale', self.arrowscale)
 
         # Conditionally apply the proper transform
         if 'transform' in kwargs and self.earth_relative:
@@ -1294,7 +1309,7 @@ def _build(self):
         self.handle = self.parent.ax.quiver(
             x_like[wind_slice], y_like[wind_slice],
             u.values[wind_slice], v.values[wind_slice],
-            color=self.color, pivot=self.pivot, scale=self.arrowscale, **kwargs)
+            **kwargs)
 
         # The order here needs to match the order of the tuple
         if self.arrowkey is not None:
@@ -1569,9 +1584,12 @@ def _build(self):
         scale = 1. if self.parent._proj_obj == ccrs.PlateCarree() else 100000.
         point_locs = self.parent._proj_obj.transform_points(ccrs.PlateCarree(), lon, lat)
         subset = reduce_point_density(point_locs, self.reduce_points * scale)
+        kwargs = self.mpl_args
+        kwargs.setdefault('clip_on', True)
+        kwargs.setdefault('transform', ccrs.PlateCarree())
+        kwargs.setdefault('fontsize', self.fontsize)
 
-        self.handle = StationPlot(self.parent.ax, lon[subset], lat[subset], clip_on=True,
-                                  transform=ccrs.PlateCarree(), fontsize=self.fontsize)
+        self.handle = StationPlot(self.parent.ax, lon[subset], lat[subset], **kwargs)
 
         for i, ob_type in enumerate(self.fields):
             field_kwargs = {}
@@ -1669,6 +1687,17 @@ class PlotGeometry(MetPyHasTraits):
     the sequence of colors as needed. Default value is black.
     """
 
+    stroke_width = Union([Instance(collections.abc.Iterable), Float()], default_value=[1],
+                   allow_none=True)
+    stroke_width.__doc__ = """Stroke width(s) for polygons and lines.
+
+    A single integer or floating point value or collection of values representing the size of
+    the stroke width. If a collection, the first value corresponds to the first Shapely
+    object in `geometry`, the second value corresponds to the second Shapely object, and so on.
+    If `stroke_width` is shorter than `geometry`, `stroke_width` cycles back to the beginning,
+    repeating the sequence of values as needed. Default value is 1.
+    """
+
     marker = Unicode(default_value='.', allow_none=False)
     marker.__doc__ = """Symbol used to denote points.
 
@@ -1847,27 +1876,38 @@ def _build(self):
                                 else self.label_edgecolor)
         self.label_facecolor = (['none'] if self.label_facecolor is None
                                 else self.label_facecolor)
+        kwargs = self.mpl_args
 
         # Each Shapely object is plotted separately with its corresponding colors and label
-        for geo_obj, stroke, fill, label, fontcolor, fontoutline in zip(
-                self.geometry, cycle(self.stroke), cycle(self.fill), cycle(self.labels),
-                cycle(self.label_facecolor), cycle(self.label_edgecolor)):
+        for geo_obj, stroke, strokewidth, fill, label, fontcolor, fontoutline in zip(
+                self.geometry, cycle(self.stroke), cycle(self.stroke_width), cycle(self.fill),
+                cycle(self.labels), cycle(self.label_facecolor), cycle(self.label_edgecolor)):
             # Plot the Shapely object with the appropriate method and colors
             if isinstance(geo_obj, (MultiPolygon, Polygon)):
-                self.parent.ax.add_geometries([geo_obj], edgecolor=stroke,
-                                              facecolor=fill, crs=ccrs.PlateCarree())
+                kwargs.setdefault('edgecolor', stroke)
+                kwargs.setdefault('linewidths', strokewidth)
+                kwargs.setdefault('facecolor', fill)
+                kwargs.setdefault('crs', ccrs.PlateCarree())
+                self.parent.ax.add_geometries([geo_obj], **kwargs)
             elif isinstance(geo_obj, (MultiLineString, LineString)):
-                self.parent.ax.add_geometries([geo_obj], edgecolor=stroke,
-                                              facecolor='none', crs=ccrs.PlateCarree())
+                kwargs.setdefault('edgecolor', stroke)
+                kwargs.setdefault('linewidths', strokewidth)
+                kwargs.setdefault('facecolor', 'none')
+                kwargs.setdefault('crs', ccrs.PlateCarree())
+                self.parent.ax.add_geometries([geo_obj], **kwargs)
             elif isinstance(geo_obj, MultiPoint):
+                kwargs.setdefault('color', fill)
+                kwargs.setdefault('marker', self.marker)
+                kwargs.setdefault('transform', ccrs.PlateCarree())
                 for point in geo_obj.geoms:
                     lon, lat = point.coords[0]
-                    self.parent.ax.plot(lon, lat, color=fill, marker=self.marker,
-                                        transform=ccrs.PlateCarree())
+                    self.parent.ax.plot(lon, lat, **kwargs)
             elif isinstance(geo_obj, Point):
+                kwargs.setdefault('color', fill)
+                kwargs.setdefault('marker', self.marker)
+                kwargs.setdefault('transform', ccrs.PlateCarree())
                 lon, lat = geo_obj.coords[0]
-                self.parent.ax.plot(lon, lat, color=fill, marker=self.marker,
-                                    transform=ccrs.PlateCarree())
+                self.parent.ax.plot(lon, lat, **kwargs)
 
             # Plot labels if provided
             if label:

tests/plots/test_declarative.py

@@ -32,7 +32,7 @@ def test_declarative_image():
 
     img = ImagePlot()
     img.data = data.metpy.parse_cf('IR')
-    img.colormap = 'Greys_r'
+    img.mpl_args = {'cmap': 'Greys_r'}
 
     panel = MapPanel()
     panel.title = 'Test'
@@ -376,7 +376,7 @@ def test_declarative_layers_plot_options():
     contour.level = 700 * units.hPa
     contour.contours = 5
     contour.linewidth = 1
-    contour.linecolor = 'grey'
+    contour.mpl_args = {'colors': 'grey'}
 
     panel = MapPanel()
     panel.area = 'us'
@@ -614,6 +614,32 @@ def test_colorfill():
     return pc.figure
 
 
+@pytest.mark.mpl_image_compare(remove_text=True, tolerance=0.009)
+def test_colorfill_args():
+    """Test that we can use ContourFillPlot."""
+    data = xr.open_dataset(get_test_data('narr_example.nc', as_file_obj=False))
+
+    contour = FilledContourPlot()
+    contour.data = data
+    contour.level = 700 * units.hPa
+    contour.field = 'Temperature'
+    contour.colormap = 'coolwarm'
+    contour.colorbar = 'vertical'
+    contour.mpl_args = {'alpha': 0.6}
+
+    panel = MapPanel()
+    panel.area = (-110, -60, 25, 55)
+    panel.layers = []
+    panel.plots = [contour]
+
+    pc = PanelContainer()
+    pc.panel = panel
+    pc.size = (12, 8)
+    pc.draw()
+
+    return pc.figure
+
+
 @pytest.mark.mpl_image_compare(remove_text=True, tolerance=0.02)
 def test_colorfill_with_image_range(cfeature):
     """Test that we can use ContourFillPlot with image_range bounds."""
@@ -783,7 +809,8 @@ def test_declarative_barb_options():
     barb.field = ['u_wind', 'v_wind']
     barb.skip = (10, 10)
     barb.color = 'blue'
-    barb.pivot = 'tip'
+    barb.pivot = 'middle'
+    barb.mpl_args = {'pivot': 'tip'}
     barb.barblength = 6.5
 
     panel = MapPanel()
@@ -812,7 +839,8 @@ def test_declarative_arrowplot():
     arrows.field = ['u_wind', 'v_wind']
     arrows.skip = (10, 10)
     arrows.color = 'blue'
-    arrows.pivot = 'mid'
+    arrows.pivot = 'tip'
+    arrows.mpl_args = {'pivot': 'mid'}
     arrows.arrowscale = 1000
 
     panel = MapPanel()
@@ -1285,6 +1313,39 @@ def test_declarative_sfc_obs(ccrs):
     return pc.figure
 
 
+@pytest.mark.mpl_image_compare(remove_text=True, tolerance=0.025)
+def test_declarative_sfc_obs_args(ccrs):
+    """Test making a surface observation plot with mpl arguments."""
+    data = pd.read_csv(get_test_data('SFC_obs.csv', as_file_obj=False),
+                       infer_datetime_format=True, parse_dates=['valid'])
+
+    obs = PlotObs()
+    obs.data = data
+    obs.time = datetime(1993, 3, 12, 12)
+    obs.time_window = timedelta(minutes=15)
+    obs.level = None
+    obs.fields = ['tmpf']
+    obs.colors = ['black']
+    obs.mpl_args = {'fontsize': 12}
+
+    # Panel for plot with Map features
+    panel = MapPanel()
+    panel.layout = (1, 1, 1)
+    panel.projection = ccrs.PlateCarree()
+    panel.area = 'in'
+    panel.layers = ['states']
+    panel.plots = [obs]
+
+    # Bringing it all together
+    pc = PanelContainer()
+    pc.size = (10, 10)
+    pc.panels = [panel]
+
+    pc.draw()
+
+    return pc.figure
+
+
 @pytest.mark.mpl_image_compare(remove_text=True, tolerance=0.016)
 @needs_cartopy
 def test_declarative_sfc_text():
@@ -1786,6 +1847,33 @@ def test_declarative_raster():
     return pc.figure
 
 
+@pytest.mark.mpl_image_compare(remove_text=True, tolerance=0.02)
+@needs_cartopy
+def test_declarative_raster_options():
+    """Test making a raster plot."""
+    data = xr.open_dataset(get_test_data('narr_example.nc', as_file_obj=False))
+
+    raster = RasterPlot()
+    raster.data = data
+    raster.colormap = 'viridis'
+    raster.field = 'Temperature'
+    raster.level = 700 * units.hPa
+    raster.mpl_args = {'alpha': 1, 'cmap': 'coolwarm'}
+
+    panel = MapPanel()
+    panel.area = 'us'
+    panel.projection = 'lcc'
+    panel.layers = ['coastline']
+    panel.plots = [raster]
+
+    pc = PanelContainer()
+    pc.size = (8.0, 8)
+    pc.panels = [panel]
+    pc.draw()
+
+    return pc.figure
+
+
 @pytest.mark.mpl_image_compare(remove_text=True, tolerance=0.607)
 @needs_cartopy
 def test_declarative_region_modifier_zoom_in():
@@ -1946,6 +2034,7 @@ def test_declarative_plot_geometry_polygons():
     geo = PlotGeometry()
     geo.geometry = [slgt_risk_polygon, enh_risk_polygon]
     geo.stroke = ['#DDAA00', '#FF6600']
+    geo.stroke_width = [1]
     geo.fill = None
     geo.labels = ['SLGT', 'ENH']
     geo.label_facecolor = ['#FFE066', '#FFA366']
@@ -1990,6 +2079,7 @@ def test_declarative_plot_geometry_lines(ccrs):
     geo.stroke = 'green'
     geo.labels = ['Irma', '+/- 0.25 deg latitude']
     geo.label_facecolor = None
+    geo.mpl_args = {'linewidth': 1}
 
     # Place plot in a panel and container
     panel = MapPanel()