Matplotlib - Overlay Funding Amount

Question

I make a candlestick with two data sets: [open, high, low, close] and volume. I am trying to overlay volumes at the bottom of the diagram as follows:

I call volume_overlay3 , but instead of bars, it fills the entire chart area. What am I doing wrong?

My other option is to use .bar (), which has no colors up and down, but will work if I could get the scale correctly:

fig = plt.figure() ax = fig.add_subplot(1,1,1) candlestick(ax, candlesticks) ax2 = ax.twinx() volume_overlay3(ax2, quotes) ax2.xaxis_date() ax2.set_xlim(candlesticks[0][0], candlesticks[-1][0]) ax.yaxis.set_label_position("right") ax.yaxis.tick_right() ax2.yaxis.set_label_position("left") ax2.yaxis.tick_left() 

Answer 1

Verdle_Volume 3 did not work for me. So I tried your idea to add a bar of strokes to the plot of the candlestick.

After creating a double axis for the volume, move this axis (make it short) and change the range of y-data of the candlestick to avoid collisions.

 import numpy as np import matplotlib import matplotlib.pyplot as plt # from matplotlib.finance import candlestick # from matplotlib.finance import volume_overlay3 # finance module is no longer part of matplotlib # see: https://github.com/matplotlib/mpl_finance from mpl_finance import candlestick_ochl as candlestick from mpl_finance import volume_overlay3 from matplotlib.dates import num2date from matplotlib.dates import date2num import matplotlib.mlab as mlab import datetime datafile = 'data.csv' r = mlab.csv2rec(datafile, delimiter=';') # the dates in my example file-set are very sparse (and annoying) change the dates to be sequential for i in range(len(r)-1): r['date'][i+1] = r['date'][i] + datetime.timedelta(days=1) candlesticks = zip(date2num(r['date']),r['open'],r['close'],r['max'],r['min'],r['volume']) fig = plt.figure() ax = fig.add_subplot(1,1,1) ax.set_ylabel('Quote ($)', size=20) candlestick(ax, candlesticks,width=1,colorup='g', colordown='r') # shift y-limits of the candlestick plot so that there is space at the bottom for the volume bar chart pad = 0.25 yl = ax.get_ylim() ax.set_ylim(yl[0]-(yl[1]-yl[0])*pad,yl[1]) # create the second axis for the volume bar-plot ax2 = ax.twinx() # set the position of ax2 so that it is short (y2=0.32) but otherwise the same size as ax ax2.set_position(matplotlib.transforms.Bbox([[0.125,0.1],[0.9,0.32]])) # get data from candlesticks for a bar plot dates = [x[0] for x in candlesticks] dates = np.asarray(dates) volume = [x[5] for x in candlesticks] volume = np.asarray(volume) # make bar plots and color differently depending on up/down for the day pos = r['open']-r['close']<0 neg = r['open']-r['close']>0 ax2.bar(dates[pos],volume[pos],color='green',width=1,align='center') ax2.bar(dates[neg],volume[neg],color='red',width=1,align='center') #scale the x-axis tight ax2.set_xlim(min(dates),max(dates)) # the y-ticks for the bar were too dense, keep only every third one yticks = ax2.get_yticks() ax2.set_yticks(yticks[::3]) ax2.yaxis.set_label_position("right") ax2.set_ylabel('Volume', size=20) # format the x-ticks with a human-readable date. xt = ax.get_xticks() new_xticks = [datetime.date.isoformat(num2date(d)) for d in xt] ax.set_xticklabels(new_xticks,rotation=45, horizontalalignment='right') plt.ion() plt.show() 

data.csv is here: http://pastebin.com/5dwzUM6e

Answer 2

See the answer here . Apparently, a mistake, and it will be fixed.

Now you need to assign the returned collection from the call to volume_overlay3 variable, and then add it to the diagram.

 vc = volume_overlay3(ax2, quotes) ax2.add_collection(vc) 

Answer 3

If you want to stack graphs on top of each other (i.e. build them on one axis), use:

 plt.hold(True)