In this article, we will see how we can plot data with timestamps using the PyQtGraph module in Python. PyQtGraph is a graphics and user interface library for Python that provides functionality commonly required in designing and science applications. Its primary goals are to provide fast, interactive graphics for displaying data (plots, video, etc.) and the second is to provide tools to aid in rapid application development (for example, property trees such as used in Qt Designer).
In order to install the PyQtGraph we use the command given below.
pip install pyqtgraph
A timestamp is a sequence of characters or encoded information identifying when a certain event occurred, usually giving date and time of day, sometimes accurate to a small fraction of a second. In this tutorial we will see how we can plot timestamps on x-axis and y-axis will have corresponding data with it.
In order to do so we have to do the following
- Import the required libraries like pyqtgraph, pyqt5, time and numpy
- Create a main window class using pyqt5
- Create a graph window having axisitem set as DateAxisItem for timestamps
- Now create a data to plot in this example we will plot the sin(1/x^2) with timestamps in the last 100 years
- With this data plot the line graph
- Add the graph and other widgets to the layout of central widget of main window.
Below is the implementation.
Python3
# importing Qt widgetsfrom PyQt5.QtWidgets import *# importing systemimport sys# time moduleimport timefrom datetime import datetime, timedelta# importing numpy as npimport numpy as np# importing pyqtgraph as pgimport pyqtgraph as pgfrom PyQt5.QtGui import *from PyQt5.QtCore import *class Window(QMainWindow): def __init__(self): super().__init__() # setting title self.setWindowTitle("PyQtGraph") # setting geometry self.setGeometry(100, 100, 900, 550) # icon icon = QIcon("skin.png") # setting icon to the window self.setWindowIcon(icon) # calling method self.UiComponents() # showing all the widgets self.show() # method for components def UiComponents(self): # creating a widget object widget = QWidget() # text text = "Timestamps Plot" # creating a label label = QLabel(text) # setting minimum width label.setMinimumWidth(130) # making label do word wrap label.setWordWrap(True) # Create a plot with a date-time axis (timestamps on x-axis) w = pg.PlotWidget(axisItems={'bottom': pg.DateAxisItem()}) # show the grids on the graph w.showGrid(x=True, y=True) # Plotting sin(1/x^2) with timestamps in the last 100 years now = time.time() # x data x = np.linspace(2 * np.pi, 1000 * 2 * np.pi, 8301) # plot the data w.plot(now - (2 * np.pi / x) ** 2 * 100 * np.pi * 1e7, np.sin(x), symbol='o') # Creating a grid layout layout = QGridLayout() # minimum width value of the label label.setMinimumWidth(130) # setting this layout to the widget widget.setLayout(layout) # adding label in the layout layout.addWidget(label, 1, 0) # plot window goes on right side, spanning 3 rows layout.addWidget(w, 0, 1, 3, 1) # setting this widget as central widget of the main window self.setCentralWidget(widget)# create pyqt5 appApp = QApplication(sys.argv)# create the instance of our Windowwindow = Window()# start the appsys.exit(App.exec()) |
Output :
