I have a timeseries data timeseries.txt. First I select a index value (here 50) and put a red line mark on that selected index value. And I want to highlight portion before(idx-20) and after(idx+20) the red line index value on the timeseries.
I wrote this code however i am able to put the red line mark on the timeseries but while using fill_betweenx it doesnot work. I hope experts may help me overcoming this problem.Thanks.
import matplotlib.pyplot as plt
import numpy as np
input_data=np.loadtxt("timeseries.txt")
time=np.arange(len(input_data))
plt.plot(time,input_data)
idx = [50]
mark = [time[i] for i in idx]
plt.plot(idx,[input_data[i] for i in mark], marker="|",color='red',markerfacecolor='none',mew=0.4,ms=30,alpha=2.0)
plt.fill_betweenx(idx-20,idx+20 alpha=0.25,color='lightsteelblue')
plt.show()
If you are looking for just a semi-transparent rectangle, you can use patches.Rectangle to draw one. Refer here. I have updated your code to add a rectangle. See if this meets your requirement. I have used a sine wave as I didn't have your data.
import matplotlib.pyplot as plt
import numpy as np
## Create sine wave
x = np.arange(100)
input_data=np.sin(2*np.pi*3*x/100)
time=np.arange(len(input_data))
plt.plot(time,input_data)
idx = [50]
mark = [time[i] for i in idx]
plt.plot(idx,[input_data[i] for i in mark], marker="|", color='red', markerfacecolor='none', mew=0.4,ms=30,alpha=2.0)
#plt.fill_betweenx(mark,idx-20,0, alpha=0.25,color='lightsteelblue')
# Create a Rectangle patch
import matplotlib.patches as patches
from matplotlib.patches import Rectangle
plt.gca().add_patch(Rectangle((idx[0]-20, -0.15), 40, .3, facecolor = 'lightsteelblue',fill=True,alpha=0.25, lw=0))
plt.show()
EDIT
Please refer to the Rectangle documentation provided earlier in the response. You will need to adjust the start coordinates (x,y) and the height and width to see how big/small you need the Rectangle. For eg: changing the rectangle code like this...
plt.gca().add_patch(Rectangle((idx[0]-10, -0.40), 20, 0.8, facecolor = 'lightsteelblue',fill=True,alpha=0.25, lw=0))
will give you this plot.
Related
I'd like to gradient-color the plot line in the Seaborn's distplot, depending on the x-axis value. For example if the value is 1, then the colour is blue, when 1.1 then it's blue and goes toward green, and so on, and so on. For example like on the plot-draft below:
The problem is, that I don't how to set colour map manually in Seaborn or how to force x-dependend coloring of the plot's curve.
Note that distplot has been deprecated. In the current seaborn version, kdeplot draws a kde curve.
You can grab the generated line with ax.get_lines(). And then create a multicolored line similar to this tutorial example.
Here is some code to demonstrate the idea (currently it would also still work with distplot):
from matplotlib import pyplot as plt
from matplotlib.collections import LineCollection
import seaborn as sns
import numpy as np
np.random.seed(1234)
data = np.random.uniform(-1, 1.1, (5, 1000)).cumsum(axis=1).ravel()
ax = sns.kdeplot(x=data)
x, y = ax.get_lines()[0].get_data()
segments = np.array([x[:-1], y[:-1], x[1:], y[1:]]).T.reshape(-1, 2, 2)
norm = plt.Normalize(x.min(), x.max())
lc = LineCollection(segments, cmap='turbo_r', norm=norm)
lc.set_array(x[:-1])
lc.set_linewidth(2)
ax.get_lines()[0].remove()
line = ax.add_collection(lc)
ax.fill_between(x, y, color='purple', alpha=0.1, hatch='xx')
ax.margins(x=0)
ax.set_ylim(ymin=0)
plt.show()
I have an image with some intersecting lines where I need to find the point of intersection. I am using cv2.goodFeaturesToTrack to find strong corners, and working on the assumption that intersections are 'strong' corners so they will get detected. But it's not a sure fire way of getting the intersection points of the two lines. Another approach is that I can get the equations of the lines and calculate the line-line intersection... or any other suggestion.
import matplotlib.pyplot as plt
import cv2
import numpy as np
img = cv2.imread('test_lines.png')
new = img.copy()
#invert
imagem = cv2.bitwise_not(img)
gray = cv2.cvtColor(imagem, cv2.COLOR_BGR2GRAY)
corners = cv2.goodFeaturesToTrack(gray, 4, 0.01, 10, blockSize = 5)
corners = np.int0(corners)
for i in corners:
import pdb; pdb.set_trace()
x, y = i.ravel()
cv2.circle(imagem, (x,y),3,255,-1)
plt.imshow(imagem)
cv2.imwrite('hough_img.png',imagem)
How to detect lines in OpenCV?
This answer was helpful in giving me some good results to begin working with. I followed the steps there to get the following result.
I have added a table to the bottom of my plot, but there are a number of issues with it:
The right has too much padding.
The left has too little padding.
The bottom has no padding.
The cells are too small for the text within them.
The table is too close to the bottom of the plot.
The cells belonging to the row names are not colored to match those of the bars.
I'm going out of my mind fiddling with this. Can someone help me fix these issues?
Here is the code (Python 3):
import seaborn as sns
import matplotlib.pyplot as plt
import numpy as np
import matplotlib
# Set styles
plt.style.use(['seaborn-paper', 'seaborn-whitegrid'])
plt.style.use(['seaborn'])
sns.set(palette='colorblind')
matplotlib.rc("font", family="Times New Roman", size=12)
labels = ['n=1','n=2','n=3','n=4','n=5']
a = [98.8,98.8,98.8,98.8,98.8]
b = [98.6,97.8,97.0,96.2,95.4]
bar_width = 0.20
data = [a,b]
print(data)
colors = plt.cm.BuPu(np.linspace(0, 0.5, len(labels)))
columns = ('n=1', 'n=2', 'n=3', 'n=4', 'n=5')
index = np.arange(len(labels))
plt.bar(index, a, bar_width)
plt.bar(index+bar_width+.02, b, bar_width)
plt.table(cellText=data,
rowLabels=['a', 'b'],
rowColours=colors,
colLabels=columns,
loc='bottom')
plt.subplots_adjust(bottom=0.7)
plt.ylabel('Some y label which effect the bottom padding!')
plt.xticks([])
plt.title('Some title')
plt.show()
This is the output:
Update
This is working now, but in case someone else is having issues: Make sure you are not viewing your plots and the changes you make to them with IntelliJ SciView as it does not represent changes accurately and introduces some formatting issues!
I think you can fix the first problem by setting the bounding box when you make the table using bbox like this:
bbox=[0, 0.225, 1, 0.2]
where the parameters are [left, bottom, width, height].
For the second issue (the coloring), that is because the color array is not corresponding to the seaborn coloring. You can query the seaborn color palette with
sns.color_palette(palette='colorblind')
this will give you a list of the colors seaborn is using.
Check the modifications below:
import seaborn as sns
import matplotlib.pyplot as plt
import numpy as np
import matplotlib
# Set styles
plt.style.use(['seaborn-paper', 'seaborn-whitegrid'])
plt.style.use(['seaborn'])
sns.set(palette='colorblind')
matplotlib.rc("font", family="Times New Roman", size=12)
labels = ['n=1','n=2','n=3','n=4','n=5']
a = [98.8,98.8,98.8,98.8,98.8]
b = [98.6,97.8,97.0,96.2,95.4]
bar_width = 0.20
data = [a,b]
colors = sns.color_palette(palette='colorblind')
columns = ('n=1', 'n=2', 'n=3', 'n=4', 'n=5')
index = np.arange(len(labels))
fig = plt.figure(figsize=(12,9))
plt.bar(index, a, bar_width)
plt.bar(index+bar_width+.02, b, bar_width)
plt.table(cellText=data,
rowLabels=[' a ', ' b '],
rowColours=colors,
colLabels=columns,
loc='bottom',
bbox=[0, 0.225, 1, 0.2])
fig.subplots_adjust(bottom=0.1)
plt.ylabel('Some y label which effect the bottom padding!')
plt.xticks([])
plt.title('Some title')
plt.show()
I also changed the subplot adjustment to subplot_adjust(bottom=0.1) because it wasn't coming out right otherwise. Here is the output:
This seems like it should be an easy fix but I can't get it to work. I would like 40°N to display in the attached plot, but setting the labels argument in drawparallels to [1,0,1,1] isn't doing the trick. That should plot the parallels lables where they intersect the left, top and bottom of the plot according to the documentation. I would also like for 0° to once again show up in the bottom right corner. Any idea of how I can fix those 2 issues?
from netCDF4 import Dataset as NetCDFFile
import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.basemap import Basemap
from mpl_toolkits.basemap import addcyclic
nc = NetCDFFile('C:/myfile.nc')
lat = nc.variables['lat'][:]
lon = nc.variables['lon'][:]
time = nc.variables['time'][:]
olr = nc.variables['olr'][:]
olr,lon = addcyclic(olr,lon)
map = Basemap(llcrnrlon=0.,llcrnrlat=-40.,urcrnrlon=360.,urcrnrlat=40.,resolution='l')
lons,lats = np.meshgrid(lon,lat)
x,y = map(lons,lats)
levels = np.arange(-19.5,20.0,0.5)
levels = levels[levels!=0]
ticks = np.arange(-20.0,20.0,4.0)
cs = map.contourf(x,y,olr[0],levels, cmap='bwr')
cbar = plt.colorbar(cs, orientation='horizontal', cmap='bwr', spacing='proportional', ticks=ticks)
cbar.set_label('Outgoing Longwave Radiation Anomalies $\mathregular{(W/m^2)}$')
map.drawcoastlines()
map.drawparallels(np.arange(-40,40,20),labels=[1,0,1,1], linewidth=0.5, fontsize=7)
map.drawmeridians(np.arange(0,360,40),labels=[1,1,0,1], linewidth=0.5, fontsize=7)
The first part of the question is easy. In order for the label to show up, you have to actually draw the parallel, but np.arange(-40,40,20) does not include 40. So, if you change that statement to np.arange(-40,41,20) your 40N label will show up.
The second part should in principle be solvable in the same way, but Basemap apparently uses the modulo of the longitudes to compute the position of the labels, so just using np.arange(0,361,40) when drawing the meridians will result in two 0 labels on top of each other. However, we can capture the labels that drawmeridians generates and manually change the position of the second 0 label. The labels are stored in a dictionary, so they are easy to deal with. To compute the x position of the last label, I compute the difference in x-position between the first and the second label, multiply that with the amount of meridians to be drawn (360/40) and add the x-position of the first label.
Here the complete example:
import matplotlib.pyplot as plt
import numpy as np
from mpl_toolkits.basemap import Basemap
map = Basemap(llcrnrlon=0.,llcrnrlat=-40.,urcrnrlon=360.,urcrnrlat=40.,resolution='l')
map.drawcoastlines()
yticks = map.drawparallels(
np.arange(-40,41,20),labels=[1,0,1,1], linewidth=0.5, fontsize=7
)
xticks = map.drawmeridians(
np.arange(0,361,40),labels=[1,1,0,1], linewidth=0.5, fontsize=7
)
first_pos = xticks[0][1][0].get_position()
second_pos = xticks[40][1][0].get_position()
last_x = first_pos[0]+(second_pos[0]-first_pos[0])*360/40
xticks[360][1][0].set_position((last_x,first_pos[1]))
plt.show()
Here the resulting plot:
Hope this helps.
I have the results of a (H,ranges) = numpy.histogram2d() computation and I'm trying to plot it.
Given H I can easily put it into plt.imshow(H) to get the corresponding image. (see http://matplotlib.org/api/pyplot_api.html#matplotlib.pyplot.imshow )
My problem is that the axis of the produced image are the "cell counting" of H and are completely unrelated to the values of ranges.
I know I can use the keyword extent (as pointed in: Change values on matplotlib imshow() graph axis ). But this solution does not work for me: my values on range are not growing linearly (actually they are going exponentially)
My question is: How can I put the value of range in plt.imshow()? Or at least, or can I manually set the label values of the plt.imshow resulting object?
Editing the extent is not a good solution.
You can just change the tick labels to something more appropriate for your data.
For example, here we'll set every 5th pixel to an exponential function:
import numpy as np
import matplotlib.pyplot as plt
im = np.random.rand(21,21)
fig,(ax1,ax2) = plt.subplots(1,2)
ax1.imshow(im)
ax2.imshow(im)
# Where we want the ticks, in pixel locations
ticks = np.linspace(0,20,5)
# What those pixel locations correspond to in data coordinates.
# Also set the float format here
ticklabels = ["{:6.2f}".format(i) for i in np.exp(ticks/5)]
ax2.set_xticks(ticks)
ax2.set_xticklabels(ticklabels)
ax2.set_yticks(ticks)
ax2.set_yticklabels(ticklabels)
plt.show()
Expanding a bit on #thomas answer
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.image as mi
im = np.random.rand(20, 20)
ticks = np.exp(np.linspace(0, 10, 20))
fig, ax = plt.subplots()
ax.pcolor(ticks, ticks, im, cmap='viridis')
ax.set_yscale('log')
ax.set_xscale('log')
ax.set_xlim([1, np.exp(10)])
ax.set_ylim([1, np.exp(10)])
By letting mpl take care of the non-linear mapping you can now accurately over-plot other artists. There is a performance hit for this (as pcolor is more expensive to draw than AxesImage), but getting accurate ticks is worth it.
imshow is for displaying images, so it does not support x and y bins.
You could either use pcolor instead,
H,xedges,yedges = np.histogram2d()
plt.pcolor(xedges,yedges,H)
or use plt.hist2d which directly plots your histogram.