NCL_scatter_1.py

This script illustrates the following concepts:

• Drawing a scatter plot

• Changing the markers in an XY plot

• Changing the marker color in an XY plot

• Changing the marker size in an XY plot

• Generating dummy data using “random.chisquared”

See following URLs to see the reproduced NCL plot & script:

• Original NCL script: https://www.ncl.ucar.edu/Applications/Scripts/scatter_1.ncl

• Original NCL plot: https://www.ncl.ucar.edu/Applications/Images/scatter_1_lg.png

Import packages

import numpy as np
import matplotlib.pyplot as plt

import geocat.viz as gv

Generate random data from a chi squared distribution with 2 dof

npts = 50
random = np.random.default_rng(seed=1)
data = random.chisquare(2.0, npts)

Plot

fig = plt.figure(figsize=(8, 8))
ax = plt.axes()

plt.plot(data, marker='o', linewidth=0, color='darkblue')

# Use geocat.viz.util convenience function to set axes parameters
gv.set_axes_limits_and_ticks(ax,
                             xlim=(0, 50),
                             ylim=(0, 10),
                             xticks=range(0, 51, 10),
                             yticks=range(0, 11, 2))

# Use geocat.viz.util convenience function to add minor and major tick lines
gv.add_major_minor_ticks(ax,
                         x_minor_per_major=5,
                         y_minor_per_major=4,
                         labelsize=14)

# Use geocat.viz.util convenience function to set titles and labels
gv.set_titles_and_labels(ax, maintitle="Scatter Plot")

plt.show()