def format_contour_axes(ax):
"""
Format the axes limits, tick marks, and tick labels for the contour plots
Args:
ax (:class: 'matplotlib.Axes'):
The set of axes to be manipulated
"""
# Use geocat.viz.util convenience function to set axes tick values
gvutil.set_axes_limits_and_ticks(ax=ax,
xlim=(-180, 180),
ylim=(-90, 90),
xticks=np.arange(-180, 181, 30),
yticks=np.arange(-90, 91, 30))
# Use geocat.viz.util convenience function to add minor and major ticks
gvutil.add_major_minor_ticks(ax, labelsize=8)
# Use geocat.viz.util convenience function to make plots look like NCL
# plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
# Remove the degree symbol from tick labels
ax.yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=''))
ax.xaxis.set_major_formatter(LongitudeFormatter(degree_symbol=''))
# Use geocat.viz.util convenience function to set titles and labels
gvutil.set_titles_and_labels(ax, maintitle='300mb', maintitlefontsize=8)
def _set_NCL_style(self,
ax,
fontsize=18,
subfontsize=18,
labelfontsize=16):
# Set NCL-style tick marks
# TODO: switch from using geocat-viz to using a geocat-lynx specific tick function
add_major_minor_ticks(ax, labelsize=10)
# Set NLC-style titles set from from initialization call (based on geocat-viz function)
if self.maintitle is not None:
if self.lefttitle is not None or self.righttitle is not None:
plt.title(self.maintitle, fontsize=fontsize + 2, y=1.12)
else:
plt.title(self.maintitle, fontsize=fontsize, y=1.04)
if self.lefttitle is not None:
plt.title(self.lefttitle, fontsize=subfontsize, y=1.04, loc='left')
if self.righttitle is not None:
plt.title(self.righttitle,
fontsize=subfontsize,
y=1.04,
loc='right')
if self.xlabel is not None:
plt.xlabel(self.xlabel, fontsize=labelfontsize)
if self.ylabel is not None:
plt.ylabel(self.ylabel, fontsize=labelfontsize)
# format axes as lat lon
add_lat_lon_ticklabels(self.ax)
def plot_labelled_filled_contours(data, ax=None):
"""
A utility function for convenience that plots labelled, filled contours with black contours
marking each level.It will return a dictionary containing three objects corresponding to the
filled contours, the black contours, and the contour labels.
"""
# Import an NCL colormap, truncating it by using geocat.viz.util convenience function
newcmp = gvutil.truncate_colormap(gvcmaps.gui_default,
minval=0.03,
maxval=0.9)
handles = dict()
handles["filled"] = data.plot.contourf(
ax=ax, # this is the axes we want to plot to
cmap=newcmp, # our special colormap
levels=levels, # contour levels specified outside this function
xticks=np.arange(-180, 181, 30), # nice x ticks
yticks=np.arange(-90, 91, 30), # nice y ticks
transform=projection, # data projection
add_colorbar=False, # don't add individual colorbars for each plot call
add_labels=False, # turn off xarray's automatic Lat, lon labels
)
# matplotlib's contourf doesn't let you specify the "edgecolors" (MATLAB terminology)
# instead we plot black contours on top of the filled contours
handles["contour"] = data.plot.contour(
ax=ax,
levels=levels,
colors="black", # note plurals in this and following kwargs
linestyles="-",
linewidths=0.5,
add_labels=False, # again turn off automatic labels
)
# Label the contours
ax.clabel(
handles["contour"],
fontsize=8,
fmt="%.0f", # Turn off decimal points
)
# Add coastlines
ax.coastlines(linewidth=0.5)
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax)
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
# Use geocat.viz.util convenience function to add main title as well as titles to left and right of the plot axes.
gvutil.set_titles_and_labels(ax,
lefttitle=data.attrs['long_name'],
lefttitlefontsize=10,
righttitle=data.attrs['units'],
righttitlefontsize=10)
return handles
def Plot(color, row, col, pos, title):
# Generate axes, using Cartopy, drawing coastlines, and adding features
projection = ccrs.PlateCarree()
ax1 = plt.subplot(row, col, pos, projection=projection)
ax1.coastlines(linewidths=0.5)
ax1.add_feature(cfeature.LAND, facecolor="lightgray")
# Import an NCL colormap
newcmp = color
# Contourf-plot data
hgt = t.plot.contourf(ax=ax1,
transform=projection,
levels=40,
vmin=100,
vmax=1600,
cmap=newcmp,
add_colorbar=False)
# Add color bar
cbar_ticks = np.arange(100, 1600, 100)
cbar = plt.colorbar(hgt,
orientation='vertical',
shrink=0.8,
pad=0.05,
extendrect=True,
ticks=cbar_ticks)
cbar.ax.tick_params(labelsize=10)
# Use geocat.viz.util convenience function to set axes parameters without calling several matplotlib functions
# Set axes limits, and tick values
gvutil.set_axes_limits_and_ticks(ax1,
xlim=(0, 90),
ylim=(0, 90),
xticks=np.linspace(-180, 180, 13),
yticks=np.linspace(-90, 90, 7))
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax1)
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax1, labelsize=12)
# Use geocat.viz.util convenience function to set titles and labels without calling several matplotlib functions
gvutil.set_titles_and_labels(ax1,
maintitle=title,
maintitlefontsize=16,
righttitlefontsize=14,
xlabel="",
ylabel="")
def make_contour_plot(ax, dataset):
lat = dataset['lat']
lon = dataset['lon']
values = dataset.data
# Import an NCL colormap
cmap = gvcmaps.BlWhRe
# Specify contour levelstamam
v = np.linspace(-0.08, 0.08, 9, endpoint=True)
# The function contourf() produces fill colors, and contour() calculates contour label locations.
cplot = ax.contourf(lon,
lat,
values,
levels=v,
cmap=cmap,
extend="both",
transform=ccrs.PlateCarree())
p = ax.contour(lon,
lat,
values,
levels=v,
linewidths=0.0,
transform=ccrs.PlateCarree())
# Label the contours
ax.clabel(p, fontsize=8, fmt="%0.2f", colors="black")
# Add coastlines
ax.coastlines(linewidth=0.5)
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax,
x_minor_per_major=3,
y_minor_per_major=4,
labelsize=10)
# Use geocat.viz.util convenience function to set axes tick values
gvutil.set_axes_limits_and_ticks(ax,
xticks=[-60, -30, 0, 30],
yticks=[40, 60, 80])
# Use geocat.viz.util convenience function to make plots look like NCL plots, using latitude & longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
return cplot, ax
def Plot(color, row, col, pos, title):
# Generate axes, using Cartopy, drawing coastlines, and adding features
projection = ccrs.PlateCarree()
ax1 = plt.subplot(row, col, pos, projection=projection)
ax1.coastlines(linewidths=0.5)
ax1.add_feature(cfeature.LAND, facecolor="lightgray")
# Import an NCL colormap
newcmp = color #gvcmaps.BlAqGrYeOrRe
# Contourf-plot data
t.plot.contourf(ax=ax1,
transform=projection,
levels=40,
vmin=100,
vmax=1600,
cmap=newcmp,
cbar_kwargs={
"orientation": "vertical",
"ticks": np.arange(100, 1600, 100),
"label": "",
"shrink": 0.8
})
# Use geocat.viz.util convenience function to set axes parameters without calling several matplotlib functions
# Set axes limits, and tick values
gvutil.set_axes_limits_and_ticks(ax1,
xlim=(0, 90),
ylim=(0, 90),
xticks=np.linspace(-180, 180, 13),
yticks=np.linspace(-90, 90, 7))
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax1)
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax1, labelsize=12)
# Use geocat.viz.util convenience function to set titles and labels without calling several matplotlib functions
gvutil.set_titles_and_labels(ax1,
maintitle=title,
maintitlefontsize=16,
righttitlefontsize=14,
xlabel="",
ylabel="")
def make_shared_plot(title):
# Generate figure (set its size (width, height) in inches) and axes using Cartopy projection
plt.figure(figsize=(10, 5.5))
ax = plt.axes(projection=ccrs.PlateCarree())
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax,
x_minor_per_major=4,
y_minor_per_major=5,
labelsize=14)
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
# Use geocat.viz.util convenience function to set axes limits & tick values without calling several matplotlib functions
gvutil.set_axes_limits_and_ticks(ax,
xlim=(-125, -70),
ylim=(25, 50),
xticks=range(-120, -75, 20),
yticks=range(30, 51, 10))
# Turn on continent shading
ax.add_feature(cartopy.feature.LAND,
edgecolor='lightgray',
facecolor='lightgray',
zorder=0)
ax.add_feature(cartopy.feature.LAKES,
edgecolor='white',
facecolor='white',
zorder=0)
# Scatter-plot the location data on the map
scatter = plt.scatter(lon, lat, c=dummy_data, cmap=cmap, zorder=1)
plt.title(title, fontsize=16, y=1.04)
return scatter, ax
# we only read every third latitude and longitude.
# This choice was made because ``geocat.viz`` doesn't offer an
# equivalent function to ncl's ``vcMinDistanceF`` yet.
file_in = xr.open_dataset('../../data/netcdf_files/uv300.nc')
# Our dataset is a subset of the data from the file
ds = file_in.isel(time=1, lon=slice(0, -1, 3), lat=slice(1, -1, 3))
###############################################################################
# Make the plot
# Set up figure and axes
fig, ax = plt.subplots(figsize=(10, 5.25))
ax = plt.axes(projection=ccrs.PlateCarree())
nclize_axis(ax)
add_lat_lon_ticklabels(ax)
# Set major and minor ticks
plt.xticks(range(-180, 181, 30))
plt.yticks(range(-90, 91, 30))
# Draw vector plot
# Notes
# 1. We plot every third vector in each direction, which is not as nice as vcMinDistanceF in NCL
# 2. There is no matplotlib equivalent to "CurlyVector"
Q = plt.quiver(ds['lon'],
ds['lat'],
ds['U'].data,
ds['V'].data,
color='black',
zorder=1,
52.7,
'500hPa',
transform=projection,
fontsize=18,
ha='center',
va='center',
color='mediumorchid',
bbox=props)
# Use geocat.viz.util convenience function to set axes tick values
gvutil.set_axes_limits_and_ticks(ax,
xticks=[100, 120, 140],
yticks=[20, 30, 40, 50])
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax,
x_minor_per_major=4,
y_minor_per_major=5,
labelsize=18)
# Use geocat.viz.util convenience function to add main title as well as titles to left and right of the plot axes.
gvutil.set_titles_and_labels(ax,
lefttitle="Temp",
lefttitlefontsize=20,
righttitle="Wind",
righttitlefontsize=20)
# Show the plot
# Add coastlines to the subplots
ax.coastlines()
# Use geocat.viz.util convenience function to add minor and major tick
# lines
gvutil.add_major_minor_ticks(ax)
# Use geocat.viz.util convenience function to set axes limits & tick
# values without calling several matplotlib functions
gvutil.set_axes_limits_and_ticks(ax,
ylim=(-60, 60),
xticks=np.linspace(-180, 180, 13),
yticks=np.linspace(-60, 60, 5))
# Use geocat.viz.util convenience function to make plots look like NCL
# plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax, zero_direction_label=True)
# Add color bar and label details (title, size, etc.)
cax = axgr.cbar_axes[0]
cax.colorbar(p)
axis = cax.axis[cax.orientation]
axis.label.set_text(r'Temperature ($^{\circ} C$)')
axis.label.set_size(16)
axis.major_ticklabels.set_size(10)
# Save figure and show
plt.savefig('linint2_points.png', dpi=300)
plt.show()
def Plot(color, ext, xext, yext, npts, title, subt, style, pt):
"""
Helper function to create two similar plots where color, extent, title,
line style, and marker style can all be customized on the same style
map projection.
Args:
color (:class: 'str'):
color for line on map in format 'color'
ext (:class: 'list'):
extent of the projection view in format [minlon, maxlon, minlat, maxlat]
xext (:class: 'list'):
start and stop points for curve in format [startlon, stoplon]
yext (:class: 'list'):
start and stop points for curve in format [startlat, stoplat]
title (:class: 'str'):
title of graph in format "Title"
style (:class: 'str'):
line style in format 'style'
pt (:class: 'str'):
marker type in format 'type'
"""
plt.figure(figsize=(8, 8))
ax = plt.axes(projection=ccrs.PlateCarree())
ax.set_extent(ext, ccrs.PlateCarree())
ax.add_feature(cfeature.LAND, color="lightgrey")
# This gets geodesic between the two points
# WGS84 ellipsoid is used
# yext and xext refer to the start and stop points for the curve
# [0] being start, [1] being stop
gl = Geodesic.WGS84.InverseLine(yext[0], xext[0], yext[1], xext[1])
npoints = npts
# Compute points on the geodesic, and plot them
# gl.s13 is the total length of the geodesic
# the points are equally spaced by 'true distance', but visually
# there is a slight distortion due to curvature/projection style
lons = []
lats = []
for ea in np.linspace(0, gl.s13, npoints):
g = gl.Position(ea, Geodesic.STANDARD | Geodesic.LONG_UNROLL)
lon2 = g["lon2"]
lat2 = g["lat2"]
lons.append(lon2)
lats.append(lat2)
plt.plot(lons, lats, style, color=color, transform=ccrs.Geodetic())
ax.plot(lons, lats, pt, transform=ccrs.PlateCarree())
plt.suptitle(title, y=0.90, fontsize=16)
# Use geocat.viz.util convenience function to set axes parameters without calling several matplotlib functions
# Set axes limits, and tick values
gvutil.set_axes_limits_and_ticks(
ax,
xlim=(-125, -60),
ylim=(15, 65),
xticks=np.linspace(-180, 180, 13),
yticks=np.linspace(0, 80, 5),
)
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
# Remove the degree symbol from tick labels
ax.yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=""))
ax.xaxis.set_major_formatter(LongitudeFormatter(degree_symbol=""))
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax, labelsize=12)
# Use geocat.viz.util convenience function to set titles and labels without calling several matplotlib functions
gvutil.set_titles_and_labels(
ax, maintitle=subt, maintitlefontsize=12, xlabel="", ylabel=""
)
plt.show()
# Use geocat.viz.util convenience function to add left and right title to the plot axes.
gvutil.set_titles_and_labels(ax[2],
lefttitle="Vector Wind",
lefttitlefontsize=12,
righttitle=ds.U.units,
righttitlefontsize=12)
# cartopy axes require this to be manual
ax[2].set_xticks(kwargs["xticks"])
ax[2].set_yticks(kwargs["yticks"])
# Use geocat.viz.util convenience function to add minor and major tick lines
[gvutil.add_major_minor_ticks(axes) for axes in ax.flat]
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
[gvutil.add_lat_lon_ticklabels(axes) for axes in ax.flat]
# Remove degree markers from x and y labels
[
axes.yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=''))
for axes in ax.flat
]
[
axes.xaxis.set_major_formatter(LongitudeFormatter(degree_symbol=''))
for axes in ax.flat
]
# Display plot
plt.show()
def make_base_plot():
# Generate axes using Cartopy projection
ax = plt.axes(projection=ccrs.PlateCarree())
# Add continents
continents = cartopy.feature.NaturalEarthFeature(
name="coastline",
category="physical",
scale="50m",
edgecolor="None",
facecolor="lightgray",
)
ax.add_feature(continents)
# Set map extent
ax.set_extent([-130, 0, -20, 40], crs=ccrs.PlateCarree())
# Define the contour levels. The top range value of 44 is not included in the levels.
levels = np.arange(-12, 44, 4)
# Using a dictionary prevents repeating the same keyword arguments twice for the contours.
kwargs = dict(
levels=levels, # contour levels specified outside this function
xticks=[-120, -90, -60, -30, 0], # nice x ticks
yticks=[-20, 0, 20, 40], # nice y ticks
transform=ccrs.PlateCarree(), # ds projection
add_colorbar=False, # don't add individual colorbars for each plot call
add_labels=False, # turn off xarray's automatic Lat, lon labels
colors="gray", # note plurals in this and following kwargs
linestyles="-",
linewidths=0.5,
)
# Contourf-plot data (for filled contours)
hdl = ds.U.plot.contour(x="lon", y="lat", ax=ax, **kwargs)
# Add contour labels. Default contour labels are sparsely placed, so we specify label locations manually.
# Label locations only need to be approximate; the nearest contour will be selected.
label_locations = [
(-123, 35),
(-116, 17),
(-94, 4),
(-85, -6),
(-95, -10),
(-85, -15),
(-70, 35),
(-42, 28),
(-54, 7),
(-53, -5),
(-39, -11),
(-28, 11),
(-16, -1),
(-8, -9), # Python allows trailing list separators.
]
ax.clabel(
hdl,
np.arange(-8, 24,
8), # Only label these contour levels: [-8, 0, 8, 16]
fontsize="small",
colors="black",
fmt="%.0f", # Turn off decimal points
manual=label_locations, # Manual label locations
inline=False
) # Don't remove the contour line where labels are located.
# Create a rectangle patch, to color the border of the rectangle a different color.
# Specify the rectangle as a corner point with width and height, to help place border text more easily.
left, width = -90, 45
bottom, height = 0, 30
right = left + width
top = bottom + height
# Draw rectangle patch on the plot
p = plt.Rectangle(
(left, bottom),
width,
height,
fill=False,
zorder=3, # Plot on top of the purple box border.
edgecolor='red',
alpha=0.5) # Lower color intensity.
ax.add_patch(p)
# Draw text labels around the box.
# Change the default padding around a text box to zero, making it a "tight" box.
# Create "text_args" to keep from repeating code when drawing text.
text_shared_args = dict(
fontsize=8,
bbox=dict(boxstyle='square, pad=0',
facecolor='white',
edgecolor='white'),
)
# Draw top text
ax.text(left + 0.6 * width,
top,
'test',
horizontalalignment='right',
verticalalignment='center',
**text_shared_args)
# Draw bottom text. Change text background to match the map.
ax.text(
left + 0.5 * width,
bottom,
'test',
horizontalalignment='right',
verticalalignment='center',
fontsize=8,
bbox=dict(boxstyle='square, pad=0',
facecolor='lightgrey',
edgecolor='lightgrey'),
)
# Draw left text
ax.text(left,
top,
'test',
horizontalalignment='center',
verticalalignment='top',
rotation=90,
**text_shared_args)
# Draw right text
ax.text(right,
bottom,
'test',
horizontalalignment='center',
verticalalignment='bottom',
rotation=-90,
**text_shared_args)
# Add lower text box. Box appears off-center, but this is to leave room
# for lower-case letters that drop lower.
ax.text(1.0,
-0.20,
"CONTOUR FROM -12 TO 40 BY 4",
fontname='Helvetica',
horizontalalignment='right',
transform=ax.transAxes,
bbox=dict(boxstyle='square, pad=0.15',
facecolor='white',
edgecolor='black'))
# Use geocat.viz.util convenience function to add main title as well as titles to left and right of the plot axes.
gvutil.set_titles_and_labels(ax,
lefttitle="Zonal Wind",
lefttitlefontsize=12,
righttitle="m/s",
righttitlefontsize=12)
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(ax, y_minor_per_major=4)
# Use geocat.viz.util convenience function to make plots look like NCL plots by using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(ax)
return ax
ylim=[-90, 90],
xticks=np.arange(-180, 181, 30),
yticks=np.arange(-90, 91, 30))
gvutil.set_axes_limits_and_ticks(axs[1],
xlim=[-180, 180],
ylim=[-90, 90],
xticks=np.arange(-180, 181, 30),
yticks=np.arange(-90, 91, 30))
# Use geocat.viz.util convenience function to add minor and major tick lines
gvutil.add_major_minor_ticks(axs[0])
gvutil.add_major_minor_ticks(axs[1])
# Use geocat.viz.util convenience function to make plots look like NCL plots by
# using latitude, longitude tick labels
gvutil.add_lat_lon_ticklabels(axs[0])
gvutil.add_lat_lon_ticklabels(axs[1])
# Remove the degree symbol from tick labels
axs[0].yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=''))
axs[0].xaxis.set_major_formatter(LongitudeFormatter(degree_symbol=''))
axs[1].yaxis.set_major_formatter(LatitudeFormatter(degree_symbol=''))
axs[1].xaxis.set_major_formatter(LongitudeFormatter(degree_symbol=''))
# Use geocat.viz.util convenience function to set titles and labels
gvutil.set_titles_and_labels(axs[0],
lefttitle='Speed',
lefttitlefontsize=10,
righttitle=U.units,
righttitlefontsize=10)
gvutil.set_titles_and_labels(axs[1],
lefttitle='Wind',