I am trying to create several plots all with the same colorbar limits in a loop.
I set the limits of the contour plot with map.contourf(x, y, U_10m, vmin=0, vmax=25) and this seems to give consistent colour scales for each plot. However, when I use cbar = plt.colorbar(boundaries=np.linspace(0,1,25), ticks=[0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24]) # sets all cbar to same limits each plot does not have the same colorbar limits (examples of two plots with different colorbars and code below).
from netCDF4 import Dataset as NetCDFFile
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
import numpy as np
def wrf_tseries_contour_plotter (
ncfile, time_ind, lowerllat, upperrlat, lowerllon, upperrlon, output_dir):
'''
EDITED FROM http://www.atmos.washington.edu/~ovens/wrfwinds.html
'''
print 'timestep:', + time_ind
#which figure is being generated 0 = 00:00, 144 = 23:50
nc = NetCDFFile(ncfile, 'r')
#
# get the actual longitudes, latitudes, and corners
lons = nc.variables['XLONG'][time_ind]
lats = nc.variables['XLAT'][time_ind]
#get the u10 to plot as a contour instead of t2m
U10_raw = nc.variables['U10'][time_ind] #61 is the index for 10:00am
V10_raw = nc.variables['V10'][time_ind]
#bodge to calculate U from U and V (u10 = sqrt(u^2+v^2))
v2 = np.square(V10_raw)
u2 = np.square(U10_raw)
U_10m = np.sqrt(u2 + v2)
# Make map
map = Basemap(projection='cyl',llcrnrlat=lowerllat,urcrnrlat=upperrlat,
llcrnrlon=lowerllon,urcrnrlon=upperrlon,
resolution='h')
# lllat, urlat,lllon, urlon set outside of f(x) lower left and
# upper right lat/lon for basemap axis limits
x, y = map(lons[:,:], lats[:,:])
map.contourf(x, y, U_10m, vmin=0, vmax=25)
map.drawcoastlines(linewidth = 0.5, color = '0.15')
#thinner lines for larger scale map
#plt.clim(0, 25) #added
cbar = plt.colorbar(boundaries=np.linspace(0,1,25), ticks=[0, 2, 4, 6,
8, 10, 12, 14, 16, 18, 20, 22, 24]) # sets all cbar to same limits
cbar.set_label('10m U (m/s)', size=12)
cbar.ax.set_yticklabels([0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24])
#cbar.set_clim(0, 25)
time_str = str(time_ind)
plt.title('gust 20070724' + '_' + time_str)
fig_name = '\gust20070724_'+ time_str + '.png'
plt.savefig(output_dir + fig_name)
plt.close()
#set inputs for wrf_tseries_contour_plotter(ncfile, time_ind, lllat, urlat,
lllon, urlon, output_dir)
ncfile = 'E:\WRFout_UK2Fino\wrfout_d03_2007-07-24_00%3A00%3A00'
tlist = np.arange(0,145)
#set the lower left/upper right lat/lon for axis limits on the maps
lowerllat=48
upperrlat=63
lowerllon=-10
upperrlon=25
#set output directory for figures
output_dir = '''C:\cbar_test'''
for time_ind in tlist:
wrf_tseries_contour_plotter(ncfile, time_ind, lowerllat, upperrlat,
lowerllon, upperrlon, output_dir)
You have to use vmin and vmax values to set boundaries of a colorbar like in this example:
import numpy as np
import matplotlib.cm as cm
import matplotlib.mlab as mlab
import matplotlib.pyplot as plt
# test data
x = np.linspace(0,15,100)
X,Y = np.meshgrid(x,x)
SPD1 = np.sqrt(X*X + Y*Y)
SPD2 = SPD1 * 1.3
fig = plt.figure()
# implement boundaries of colorbar and it ticks
vmin, vmax = 0, 26
levels = np.linspace(vmin,vmax,14)
# 1st subplot
ax1 = fig.add_subplot(221)
# Set contour levels and limits
CF1 = ax1.contourf(X, Y, SPD1, levels=levels, vmax=vmax, vmin=vmin)
cbar = plt.colorbar(CF1)
cbar.set_label('10m U (m/s)', size=12)
#2nd subplot
ax1 = fig.add_subplot(222)
CF1 = ax1.contourf(X, Y, SPD2, levels=levels, vmax=vmax, vmin=vmin)
cbar = plt.colorbar(CF1)
cbar.set_label('10m U (m/s)', size=12)
plt.tight_layout()
plt.show()
However you have to select vmin, vmax correctly because of if your values are outside boundaries of colorbar they will not shown (right upper corner of 2nd subplot).
Related
I have 9 temperature points. 1 in the center and 8 on the circle. I need to create a heatmap in a circle. I set the points at which to perform calculations, and use the scipy.interpolate.griddata, but the full circle is not drawn, program draws an octagon. How can i fill in the missing parts?
import scipy.interpolate
import numpy
import matplotlib
import matplotlib.pyplot as plt
import math
# close old plots
plt.close("all")
# some parameters
xy_center = [2,2] # center of the plot
radius = 2 # radius
# mostly original code
meanR = [33.9, 34.2, 33.1, 33.5, 33., 32.7, 32.3, 31.8, 35.]
x = numpy.array([2, 2, 2+math.sqrt(2), 4, 2+math.sqrt(2), 2, 2+(-math.sqrt(2)), 0, 2+(-math.sqrt(2))])
y = numpy.array([2, 4, 2+math.sqrt(2), 2, 2+(-math.sqrt(2)), 0, 2+(-math.sqrt(2)), 2, 2+math.sqrt(2)])
z = meanR
xi, yi = numpy.mgrid[x.min():x.max():500j, y.min():y.max():500j]
zi = scipy.interpolate.griddata((x, y), z, (xi, yi), method='cubic')
# make figure
fig = plt.figure(figsize=(10, 10))
# set aspect = 1 to make it a circle
ax = fig.add_subplot(111, aspect = 1)
# use different number of levels for the fill and the lines
CS = ax.contourf(xi, yi, zi, 300, cmap=plt.cm.viridis, zorder=1)
# make a color bar
cbar = fig.colorbar(CS, ax=ax)
# add the data points
ax.scatter(x, y, marker = 'o', c = 'b', s = 15, zorder = 3)
for i in range(9):
ax.annotate(str(z[i]), (x[i],y[i]))
# draw a circle
circle = matplotlib.patches.Circle(xy = xy_center, radius = radius, edgecolor = "k", facecolor = "none")
ax.add_patch(circle)
# remove the ticks
ax.set_xticks([])
ax.set_yticks([])
# set axes limits
ax.set_xlim(-0.5, 4.5)
ax.set_ylim(-0.5, 4.5)
plt.show()
Radial basis functions (Rbf) can be used to interpolate/extrapolate your data.
scipy.interpolation Here is a modified code that produces the plot you need.
import numpy as np
import matplotlib
import matplotlib.pyplot as plt
import math
from scipy.interpolate import Rbf
# some parameters
xy_center = [2,2] # center of the plot
radius = 2 # radius
# Data part
# ---------
# mostly original code
meanR = [33.9, 34.2, 33.1, 33.5, 33., 32.7, 32.3, 31.8, 35.] #9 points data
x = np.array([2, 2, 2+math.sqrt(2), 4, 2+math.sqrt(2), 2, 2+(-math.sqrt(2)), 0, 2+(-math.sqrt(2))])
y = np.array([2, 4, 2+math.sqrt(2), 2, 2+(-math.sqrt(2)), 0, 2+(-math.sqrt(2)), 2, 2+math.sqrt(2)])
z = meanR
# use RBF (Radial basis functions) that allows extrapolation
rbf = Rbf(x, y, z, epsilon=radius+1) #epsilon is based on some parameters of the data
# Interpolation/extrapolation
# ---------------------------
xi, yi = np.mgrid[x.min():x.max():500j, y.min():y.max():500j]
# applies and get inter/extra-polated values
zi = rbf(xi, yi)
# make zi outside circle --> np.none
midr,midc = zi.shape[0]/2, zi.shape[1]/2
for er in range(zi.shape[0]):
for ec in range(zi.shape[1]):
if np.abs(math.sqrt((er-midr)**2 + (ec-midc)**2))>zi.shape[0]/2:
# outside the circle, dont plot this pixel
zi[er][ec] = np.nan
pass
pass
# make figure
fig = plt.figure(figsize=(8, 8))
# set aspect = 1 to make it a circle
ax = fig.add_subplot(111, aspect = 1)
# add the data points
ax.scatter(x, y, marker = 'o', c = 'b', s = 15, zorder = 3)
for i in range(9):
ax.annotate(str(z[i]), (x[i],y[i]))
# draw a circle
circle = matplotlib.patches.Circle(xy = xy_center, radius = radius, edgecolor = "k", facecolor = "none")
ax.add_patch(circle)
CS = ax.contourf(xi, yi, zi, 300, cmap=plt.cm.viridis, zorder=1)
cbar = fig.colorbar(CS, ax=ax, shrink=0.7) # make a color bar
# remove the ticks
ax.set_xticks([])
ax.set_yticks([])
# set axes limits
ax.set_xlim(-0.5, 4.5)
ax.set_ylim(-0.5, 4.5)
plt.show()
The result:
Here is a part of the plot that I have
I need to create TrendLine that would be extended to the 3th
quarter of this plot... I can's think of any solution.
import matplotlib.pyplot as plt
import warnings
warnings.filterwarnings('ignore')
x = [1, 8, 12, 20]
y = [1, 8.4, 12.5, 20]
fig = plt.figure(figsize=(20,20))
ax = fig.add_subplot()
ax.set_xlim(-30, 30)
ax.set_ylim(-20, 20)
plt.subplot().spines['left'].set_position('center')
plt.subplot().spines['bottom'].set_position('center')
plt.plot(x,y, 'b.', ms=20)
plt.minorticks_on()
ax.grid(True, which='both')
mean_line = ax.plot()
z = np.polyfit(x, y, 1)
p = np.poly1d(z)
plt.plot(x,p(x),"r--")
plt.show()
I don't think reverse x and y would do the job, it would be limited to the poly1d that pass (0,0)
I think the extending method should be using the fitted line itself.
so a more general method is extend the x and use the poly1d(z) to calculate an extended line. z is description of the fitted line, so feeding x value to z would draw the line.
import matplotlib.pyplot as plt
import numpy as np
import warnings
warnings.filterwarnings('ignore')
x = [1, 8, 12, 20]
y = [1, 8.4, 12.5, 20]
# make an xx that with from -20 to 20
#xx =np.array(x)
#xx = sorted(np.concatenate((-xx, xx), axis=0))
xx = [-20, 20] # also work
fig, ax = plt.subplots(figsize=(10,10))
ax.set_xlim(-30, 30)
ax.set_ylim(-20, 20)
plt.subplot().spines['left'].set_position('center')
plt.subplot().spines['bottom'].set_position('center')
plt.subplot().spines['right'].set_color('none')
plt.subplot().spines['top'].set_color('none')
plt.plot(x,y, 'b.', ms=20)
plt.minorticks_on()
#ax.grid(True, which='both')
plt.subplot().grid(True, which='both')
mean_line = ax.plot()
z = np.polyfit(x, y, 1)
p = np.poly1d(z)
plt.plot(xx,p(xx),"r--")
plt.show()
if you zoomin near the (0,0), you should see it's not passing the origin point.
zoomed in near (0,0)
result image
I don't have any experience with trendlines, but I created a composite of existing x and y values with different signs and drew the following graph.
import matplotlib.pyplot as plt
import warnings
warnings.filterwarnings('ignore')
x = [1, 8, 12, 20]
y = [1, 8.4, 12.5, 20]
fig = plt.figure(figsize=(10,10))
ax = fig.add_subplot()
ax.set_xlim(-30, 30)
ax.set_ylim(-20, 20)
plt.subplot().spines['left'].set_position('center')
plt.subplot().spines['bottom'].set_position('center')
plt.plot(x,y, 'b.', ms=20)
plt.minorticks_on()
ax.grid(True, which='both')
mean_line = ax.plot()
# update
xx =np.array(x)
xx = sorted(np.concatenate((-xx, xx), axis=0))
yy =np.array(y)
yy = sorted(np.concatenate((-yy, yy), axis=0))
z = np.polyfit(xx, yy, 1)
p = np.poly1d(z)
plt.plot(xx,p(xx),"r--")
plt.show()
I am trying to create a graph with a secondary x-axis however I want the label and the ticks of the secondary x-axis to lie under the first. I have currently only found methods to move it to the bottom and not to an exact position. I have attached an image of what I am trying to achieve.
y = [3, 5, 2, 8, 7]
x = [[10, 11, 12, 13, 14], [36, 39.6, 43.2, 46.8, 50.4]]
labels = ['m/s', 'km/hr']
fig,ax = plt.subplots()
ax.plot(x[0], y)
ax.set_xlabel("Velocity m/s")
ax.set_ylabel("Time /mins")
ax2=ax.twiny()
ax2.plot(x[1], y)
ax2.set_xlabel("Velocity km/hr")
plt.show()
Answer
Firstly you have to include the required libraries:
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import host_subplot
import mpl_toolkits.axisartist as AA
then you could generate the first axis with
ax = host_subplot(111, axes_class = AA.Axes, figure = fig)
then generate the secondary axis by
ax2=ax.twiny()
At this point you need to make some space for the secondary axis, therefore you should raise the bottom of the plot area with
plt.subplots_adjust(bottom = 0.2)
and finally position the secondary axis under the first one by
offset = -40
new_fixed_axis = ax2.get_grid_helper().new_fixed_axis
ax2.axis['bottom'] = new_fixed_axis(loc = 'bottom',
axes = ax2,
offset = (0, offset))
ax2.axis['bottom'].toggle(all = True)
Whole code
import matplotlib.pyplot as plt
from mpl_toolkits.axes_grid1 import host_subplot
import mpl_toolkits.axisartist as AA
y = [3, 5, 2, 8, 7]
x = [[10, 11, 12, 13, 14], [36, 39.6, 43.2, 46.8, 50.4]]
labels = ['m/s', 'km/hr']
fig = plt.figure()
# generate the first axis
ax = host_subplot(111, axes_class = AA.Axes, figure = fig)
ax.plot(x[0], y)
ax.set_xlabel("Velocity m/s")
ax.set_ylabel("Time /mins")
ax2=ax.twiny()
# make space for the secondary axis
plt.subplots_adjust(bottom = 0.2)
# set position ax2 axis
offset = -40
new_fixed_axis = ax2.get_grid_helper().new_fixed_axis
ax2.axis['bottom'] = new_fixed_axis(loc = 'bottom',
axes = ax2,
offset = (0, offset))
ax2.axis['bottom'].toggle(all = True)
ax2.plot(x[1], y)
ax2.set_xlabel("Velocity km/hr")
plt.show()
Result
I have a 3d plot of a disk, here is the code:
ri = 100
ra = 300
h=20
# input xy coordinates
xy = np.array([[ri,0],[ra,0],[ra,h],[ri,h],[ri,0]])
# radial component is x values of input
r = xy[:,0]
# angular component is one revolution of 30 steps
phi = np.linspace(0, 2*np.pi, 50)
# create grid
R,Phi = np.meshgrid(r,phi)
# transform to cartesian coordinates
X = R*np.cos(Phi)
Y = R*np.sin(Phi)
# Z values are y values, repeated 30 times
Z = np.tile(xy[:,1],len(Y)).reshape(Y.shape)
fig = plt.figure()
ax = fig.add_subplot(1, 1, 1, projection='3d')
ax.set_zlim(0,200)
ax.plot_surface(X, Y, Z, alpha=0.5, color='grey', rstride=1, cstride=1)
I get this nice plot:
Further I have this plot:
The code is:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
arr = np.array([[100, 15],
[114.28, 17],
[128.57, 18],
[142.85, 19],
[157.13, 22],
[171.13, 24],
[185.69, 25],
[199.97, 27],
[214.25, 28],
[228.53, 30],
[242.81, 31],
[257.09, 35],
[271.37, 36],
[288.65, 37],
[300, 38]])
#interpolating between the single values of the arrays
new_x = np.concatenate([np.linspace(arr[i,0],arr[i+1,0], num=50)
for i in range(len(arr)-1)])
new_y = np.interp(new_x, arr[:,0], arr[:,1])
t=np.arange(700)
p = plt.scatter(new_x,new_y,c=t, cmap="jet")
#inserting colorbar
cax, _ = mpl.colorbar.make_axes(plt.gca(), shrink=0.8)
cbar = mpl.colorbar.ColorbarBase(cax, cmap='jet', label='testvalues',
norm=mpl.colors.Normalize(15, 40))
plt.show()
Now my question:
Is there a way to plot this 2d graph into my 3d environment? Further is it possible to create a surface out of this line (points) by rotating them around the middlepoint ? I tried it the same way like I did it with my disk but I failed because I think I need a closed contour ? Here is a picture to understand better what I want:
I'm not sure how you want to include your 2d plot, so here's how you do it as a surface of revolution.
Your new_x corresponds to radial distance, new_y corresponds to height. So we need to generate an array of angles for which to generate the "cone":
from matplotlib import cm
tmp_phi = np.linspace(0,2*np.pi,50)[:,None] # angle data
linesurf_x = new_x*np.cos(tmp_phi)
linesurf_y = new_x*np.sin(tmp_phi)
linesurf_z = np.broadcast_to(new_y, linesurf_x.shape)
linesurf_c = np.broadcast_to(t, linesurf_x.shape) # color according to t
colors = cm.jet(linesurf_c/linesurf_c.max()) # grab actual colors for the surface
ax.plot_surface(linesurf_x, linesurf_y, linesurf_z, facecolors=colors,
rstride=1, cstride=1)
Result:
import matplotlib.pyplot as plt
gridnumber = range(1,4)
b1 = plt.bar(gridnumber, [0.2, 0.3, 0.1], width=0.4,
label="Bar 1", align="center")
b2 = plt.bar(gridnumber, [0.3, 0.2, 0.2], color="red", width=0.4,
label="Bar 2", align="center")
plt.ylim([0,0.5])
plt.xlim([0,4])
plt.xticks(gridnumber)
plt.legend()
plt.show()
Currently b1 and b2 overlap each other. How do I plot them separately like so:
There is an example in the matplotlib site. Basically, you just shift the x values by width. Here is the relevant bit:
import numpy as np
import matplotlib.pyplot as plt
N = 5
menMeans = (20, 35, 30, 35, 27)
menStd = (2, 3, 4, 1, 2)
ind = np.arange(N) # the x locations for the groups
width = 0.35 # the width of the bars
fig = plt.figure()
ax = fig.add_subplot(111)
rects1 = ax.bar(ind, menMeans, width, color='royalblue', yerr=menStd)
womenMeans = (25, 32, 34, 20, 25)
womenStd = (3, 5, 2, 3, 3)
rects2 = ax.bar(ind+width, womenMeans, width, color='seagreen', yerr=womenStd)
# add some
ax.set_ylabel('Scores')
ax.set_title('Scores by group and gender')
ax.set_xticks(ind + width / 2)
ax.set_xticklabels( ('G1', 'G2', 'G3', 'G4', 'G5') )
ax.legend( (rects1[0], rects2[0]), ('Men', 'Women') )
plt.show()
Below answer will explain each and every line of code in the simplest manner possible:
# Numbers of pairs of bars you want
N = 3
# Data on X-axis
# Specify the values of blue bars (height)
blue_bar = (23, 25, 17)
# Specify the values of orange bars (height)
orange_bar = (19, 18, 14)
# Position of bars on x-axis
ind = np.arange(N)
# Figure size
plt.figure(figsize=(10,5))
# Width of a bar
width = 0.3
# Plotting
plt.bar(ind, blue_bar , width, label='Blue bar label')
plt.bar(ind + width, orange_bar, width, label='Orange bar label')
plt.xlabel('Here goes x-axis label')
plt.ylabel('Here goes y-axis label')
plt.title('Here goes title of the plot')
# xticks()
# First argument - A list of positions at which ticks should be placed
# Second argument - A list of labels to place at the given locations
plt.xticks(ind + width / 2, ('Xtick1', 'Xtick3', 'Xtick3'))
# Finding the best position for legends and putting it
plt.legend(loc='best')
plt.show()
Sometimes could be tricky to find the right bar width. I usually use this np.diff to find the right dimension.
import numpy as np
import matplotlib.pyplot as plt
#The data
womenMeans = (25, 32, 34, 20, 25)
menMeans = (20, 35, 30, 35, 27)
indices = [5.5,6,7,8.5,8.9]
#Calculate optimal width
width = np.min(np.diff(indices))/3
fig = plt.figure()
ax = fig.add_subplot(111)
# matplotlib 3.0 you have to use align
ax.bar(indices-width,womenMeans,width,color='b',label='-Ymin',align='edge')
ax.bar(indices,menMeans,width,color='r',label='Ymax',align='edge')
ax.set_xlabel('Test histogram')
plt.show()
# matplotlib 2.0 (you could avoid using align)
# ax.bar(indices-width,womenMeans,width,color='b',label='-Ymin')
# ax.bar(indices,menMeans,width,color='r',label='Ymax')
This is the result:
What if my indices on my x axis are nominal values like names:
#
import numpy as np
import matplotlib.pyplot as plt
# The data
womenMeans = (25, 32, 34, 20, 25)
menMeans = (20, 35, 30, 35, 27)
indices = range(len(womenMeans))
names = ['Asian','European','North Amercian','African','Austrailian','Martian']
# Calculate optimal width
width = np.min(np.diff(indices))/3.
fig = plt.figure()
ax = fig.add_subplot(111)
ax.bar(indices-width/2.,womenMeans,width,color='b',label='-Ymin')
ax.bar(indices+width/2.,menMeans,width,color='r',label='Ymax')
#tiks = ax.get_xticks().tolist()
ax.axes.set_xticklabels(names)
ax.set_xlabel('Test histogram')
plt.show()
Here are two examples of creating a side-by-side bar chart when you have more than two "categories" in a group.
Manual Method
Manually set the position and width of each bar.
import numpy as np
import matplotlib.pyplot as plt
from matplotlib import ticker
coins = ['penny', 'nickle', 'dime', 'quarter']
worth = np.array([.01, .05, .10, .25])
# Coin values times *n* coins
# This controls how many bars we get in each group
values = [worth*i for i in range(1,6)]
n = len(values) # Number of bars to plot
w = .15 # With of each column
x = np.arange(0, len(coins)) # Center position of group on x axis
for i, value in enumerate(values):
position = x + (w*(1-n)/2) + i*w
plt.bar(position, value, width=w, label=f'{i+1}x')
plt.xticks(x, coins);
plt.ylabel('Monetary Value')
plt.gca().yaxis.set_major_formatter(ticker.FormatStrFormatter('$%.2f'))
plt.legend()
Pandas Method
If you put the data into a pandas DataFrame, pandas will do the hard stuff for you.
import pandas as pd
coins = ['penny', 'nickle', 'dime', 'quarter']
worth = [0.01, 0.05, 0.10, 0.25]
df = pd.DataFrame(worth, columns=['1x'], index=coins)
df['2x'] = df['1x'] * 2
df['3x'] = df['1x'] * 3
df['4x'] = df['1x'] * 4
df['5x'] = df['1x'] * 5
from matplotlib import ticker
import matplotlib.pyplot as plt
df.plot(kind='bar')
plt.ylabel('Monetary Value')
plt.gca().yaxis.set_major_formatter(ticker.FormatStrFormatter('$%.2f'))
plt.gca().xaxis.set_tick_params(rotation=0)
Pandas creates a similar figure...