histogram

I'm trying to plot a 2D histogram in Python using these code from math import * import pylab as p import matplotlib.pyplot as plt import numpy as np x=part.points[:,0] y=part.points[:,1] z=part.points[:,2] H, xedges, yedges = np.histogram2d(x, y, bins=(128,128)) H.shape, xedges.shape, yedges.shape extent = [yedges[0], yedges[-1], xedges[-1], xedges[0]] plt.imshow(H, extent=extent, interpolation='nearest') plt.colorbar() plt.xlabel("x") plt.ylabel("y") plt.show() Every thing works fine: I have a color bar which represent the counts in each cells. The thing is that I would like to have the log

This question is related to gnuplot histogram: How to put values on top of bars . I have a datafile file.dat : x y1 y2 1 2 3 2 3 4 3 4 5 and the gnuplot: set style data histogram; set style histogram rowstacked; plot newhistogram 'foo', 'file.dat' u 2:xtic(1) t col, '' u 3 t col; Now I want to place the sums of columns 2 and 3 above the bars. The obvious solution plot newhistogram 'foo', 'file.dat' u 2:xtic(1) t col, '' u 3 t col, \ '' u ($0-1):($2+$3+0.2):($2+$3) notitle w labels font "Arial,8"; puts the labels in the correct place, but the calculated sum is wrong. That is, in ($0-1):($2+$3+0

How can I convert an RGB histogram of an image to create a histogram showing the combined colors along with correct color wavelength range? Example code: pkg load image f=imread('/tmp/marbles.jpg'); f=uint8(f); %need to convert back to uint8 to show picture %Split into RGB Channels f_red = f(:,:,1); f_green = f(:,:,2); f_blue = f(:,:,3); %Get histValues for each channel [y_f_red, x] = imhist(f_red); [y_f_green, x] = imhist(f_green); [y_f_blue, x] = imhist(f_blue); subplot (2,1,1); imshow(f); subplot (2,1,2); plot(x, y_f_red, 'r', x, y_f_green, 'g', x, y_f_blue, 'b'); Example image along with

I am trying to plot some histogrammed data on a polar axis but it wont seem to work properly. An example is below, I use the custom projection found How to make the angles in a matplotlib polar plot go clockwise with 0° at the top? it works for a scatter plot so I think my problem is with the histogram function. This has been driving me nuts all day, does anyone know what I am doing wrong........... import random import numpy as np import matplotlib.pyplot as plt baz = np.zeros((20)) freq = np.zeros((20)) pwr = np.zeros((20)) for x in range(20): baz[x] = random.randint(20,25)*10 freq[x] =

I have two sets of different sizes that I'd like to plot on the same histogram. However, since one set has ~330,000 values and the other has about ~16,000 values, their frequency histograms are hard to compare. I'd like to plot a histogram comparing the two sets such that the y-axis is the % of occurrences in that bin. My code below gets close to this, except that rather than having the individual bin values sum to 1.0, the integral of the histogram sums to 1.0 (this is because of the normed=True parameter). How can I achieve my goal? I've already tried manually calculating the % frequency and

I could not find a solution to the following issue I am facing. All SO questions on multi-axis talk about line plots, but I am looking for histograms. The y-range for the bars are different, so one set of bars are not really seen because of the scale. Here is the data: Metric A B M1 0.613416301 0.543734744 M2 0.000195961 0.000100190 Here is the MWE: reset set term postscript eps size 5.5,4.5 enhanced color font 'Arial-Bold' 25 set out 'histplot.eps' set key right set style histogram cluster gap 2 set style data histograms set style fill pattern 1.00 border set y2range [0.0001:0.0002] plot

I am looking for a way to get a histogram of an image on the iPhone. The OpenCV library is way too big to be included in my app (OpenCV is about 70MB compiled), but I can use OpenGL. However, I have no idea on how to do either of these. I have found how to get the pixels of the image, but cannot form a histogram. This seems like it should be simple, but I don't know how to store uint8_t into an array. Here is the relevant question/answer for finding pixels: Getting RGB pixel data from CGImage The uint8_t* is just a pointer to a c array containing the bytes of the given color, i.e. {r, g, b, a}