|
| 1 | +""" |
| 2 | +================ |
| 3 | +Ishikawa Diagram |
| 4 | +================ |
| 5 | +
|
| 6 | +Ishikawa Diagrams, fishbone diagrams, herringbone diagrams, or cause-and-effect |
| 7 | +diagrams are used to identify problems in a system by showing how causes and |
| 8 | +effects are linked. |
| 9 | +Source: https://en.wikipedia.org/wiki/Ishikawa_diagram |
| 10 | +
|
| 11 | +""" |
| 12 | +import matplotlib.pyplot as plt |
| 13 | + |
| 14 | +from matplotlib.patches import Polygon, Wedge |
| 15 | + |
| 16 | +# Create the fishbone diagram |
| 17 | +fig, ax = plt.subplots(figsize=(10, 6), layout='constrained') |
| 18 | +ax.set_xlim(-5, 5) |
| 19 | +ax.set_ylim(-5, 5) |
| 20 | +ax.axis('off') |
| 21 | + |
| 22 | + |
| 23 | +def problems(data: str, |
| 24 | + problem_x: float, problem_y
10000
span>: float, |
| 25 | + prob_angle_x: float, prob_angle_y: float): |
| 26 | + """ |
| 27 | + Draw each problem section of the Ishikawa plot. |
| 28 | +
|
| 29 | + Parameters |
| 30 | + ---------- |
| 31 | + data : str |
| 32 | + The category name. |
| 33 | + problem_x, problem_y : float, optional |
| 34 | + The `X` and `Y` positions of the problem arrows (`Y` defaults to zero). |
| 35 | + prob_angle_x, prob_angle_y : float, optional |
| 36 | + The angle of the problem annotations. They are angled towards |
| 37 | + the tail of the plot. |
| 38 | +
|
| 39 | + Returns |
| 40 | + ------- |
| 41 | + None. |
| 42 | +
|
| 43 | + """ |
| 44 | + ax.annotate(str.upper(data), xy=(problem_x, problem_y), |
| 45 | + xytext=(prob_angle_x, prob_angle_y), |
| 46 | + fontsize='10', |
| 47 | + color='white', |
| 48 | + weight='bold', |
| 49 | + xycoords='data', |
| 50 | + verticalalignment='center', |
| 51 | + horizontalalignment='center', |
| 52 | + textcoords='offset fontsize', |
| 53 | + arrowprops=dict(arrowstyle="->", facecolor='black'), |
| 54 | + bbox=dict(boxstyle='square', |
| 55 | + facecolor='tab:blue', |
| 56 | + pad=0.8)) |
| 57 | + |
| 58 | + |
| 59 | +def causes(data: list, cause_x: float, cause_y: float, |
| 60 | + cause_xytext=(-9, -0.3), top: bool = True): |
| 61 | + """ |
| 62 | + Place each cause to a position relative to the problems |
| 63 | + annotations. |
| 64 | +
|
| 65 | + Parameters |
| 66 | + ---------- |
| 67 | + data : indexable object |
| 68 | + The input data. IndexError is |
| 69 | + raised if more than six arguments are passed. |
| 70 | + cause_x, cause_y : float |
| 71 | + The `X` and `Y` position of the cause annotations. |
| 72 | + cause_xytext : tuple, optional |
| 73 | + Adjust to set the distance of the cause text from the problem |
| 74 | + arrow in fontsize units. |
| 75 | + top : bool |
| 76 | +
|
| 77 | + Returns |
| 78 | + ------- |
| 79 | + None. |
| 80 | +
|
| 81 | + """ |
| 82 | + for index, cause in enumerate(data): |
| 83 | + # First cause annotation is placed in the middle of the problems arrow |
| 84 | + # and each subsequent cause is plotted above or below it in succession. |
| 85 | + |
| 86 | + # [<x pos>, [<y pos top>, <y pos bottom>]] |
| 87 | + coords = [[0, [0, 0]], |
| 88 | + [0.23, [0.5, -0.5]], |
| 89 | + [-0.46, [-1, 1]], |
| 90 | + [0.69, [1.5, -1.5]], |
| 91 | + [-0.92, [-2, 2]], |
| 92 | + [1.15, [2.5, -2.5]]] |
| 93 | + if top: |
| 94 | + cause_y += coords[index][1][0] |
| 95 | + else: |
| 96 | + cause_y += coords[index][1][1] |
| 97 | + cause_x -= coords[index][0] |
| 98 | + |
| 99 | + ax.annotate(cause, xy=(cause_x, cause_y), |
| 100 | + horizontalalignment='center', |
| 101 | + xytext=cause_xytext, |
| 102 | + fontsize='9', |
| 103 | + xycoords='data', |
| 104 | + textcoords='offset fontsize', |
| 105 | + arrowprops=dict(arrowstyle="->", |
| 106 | + facecolor='black')) |
| 107 | + |
| 108 | + |
| 109 | +def draw_body(data: dict): |
| 110 | + """ |
| 111 | + Place each section in its correct place by changing |
| 112 | + the coordinates on each loop. |
| 113 | +
|
| 114 | + Parameters |
| 115 | + ---------- |
| 116 | + data : dict |
| 117 | + The input data (can be list or tuple). ValueError is |
| 118 | + raised if more than six arguments are passed. |
| 119 | +
|
| 120 | + Returns |
| 121 | + ------- |
| 122 | + None. |
| 123 | +
|
| 124 | + """ |
| 125 | + second_sections = [] |
| 126 | + third_sections = [] |
| 127 | + # Resize diagram to automatically scale in response to the number |
| 128 | + # of problems in the input data. |
| 129 | + if len(data) == 1 or len(data) == 2: |
| 130 | + spine_length = (-2.1, 2) |
| 131 | + head_pos = (2, 0) |
| 132 | + tail_pos = ((-2.8, 0.8), (-2.8, -0.8), (-2.0, -0.01)) |
| 133 | + first_section = [1.6, 0.8] |
| 134 | + elif len(data) == 3 or len(data) == 4: |
| 135 | + spine_length = (-3.1, 3) |
| 136 | + head_pos = (3, 0) |
| 137 | + tail_pos = ((-3.8, 0.8), (-3.8, -0.8), (-3.0, -0.01)) |
| 138 | + first_section = [2.6, 1.8] |
| 139 | + second_sections = [-0.4, -1.2] |
| 140 | + else: # len(data) == 5 or 6 |
| 141 | + spine_length = (-4.1, 4) |
| 142 | + head_pos = (4, 0) |
| 143 | + tail_pos = ((-4.8, 0.8), (-4.8, -0.8), (-4.0, -0.01)) |
| 144 | + first_section = [3.5, 2.7] |
| 145 | + second_sections = [1, 0.2] |
| 146 | + third_sections = [-1.5, -2.3] |
| 147 | + |
| 148 | + # Change the coordinates of the annotations on each loop. |
| 149 | + for index, problem in enumerate(data.values()): |
| 150 | + top_row = True |
| 151 | + cause_arrow_y = 1.7 |
| 152 | + if index % 2 != 0: # Plot problems below the spine. |
| 153 | + top_row = False |
| 154 | + y_prob_angle = -16 |
| 155 | + cause_arrow_y = -1.7 |
| 156 | + else: # Plot problems above the spine. |
| 157 | + y_prob_angle = 16 |
| 158 | + # Plot the 3 sections in pairs along the main spine. |
| 159 | + if index in (0, 1): |
| 160 | + prob_arrow_x = first_section[0] |
| 161 | + cause_arrow_x = first_section[1] |
| 162 | + elif index in (2, 3): |
| 163 | + prob_arrow_x = second_sections[0] |
| 164 | + cause_arrow_x = second_sections[1] |
| 165 | + else: |
| 166 | + prob_arrow_x = third_sections[0] |
| 167 | + cause_arrow_x = third_sections[1] |
| 168 | + if index > 5: |
| 169 | + raise ValueError(f'Maximum number of problems is 6, you have entered ' |
| 170 | + f'{len(data)}') |
| 171 | + |
| 172 | + # draw main spine |
| 173 | + ax.plot(spine_length, [0, 0], color='tab:blue', linewidth=2) |
| 174 | + # draw fish head |
| 175 | + ax.text(head_pos[0] + 0.1, head_pos[1] - 0.05, 'PROBLEM', fontsize=10, |
| 176 | + weight='bold', color='white') |
| 177 | + semicircle = Wedge(head_pos, 1, 270, 90, fc='tab:blue') |
| 178 | + ax.add_patch(semicircle) |
| 179 | + # draw fishtail |
| 180 | + triangle = Polygon(tail_pos, fc='tab:blue') |
| 181 | + ax.add_patch(triangle) |
| 182 | + # Pass each category name to the problems function as a string on each loop. |
| 183 | + problems(list(data.keys())[index], prob_arrow_x, 0, -12, y_prob_angle) |
| 184 | + # Start the cause function with the first annotation being plotted at |
| 185 | + # the cause_arrow_x, cause_arrow_y coordinates. |
| 186 | + causes(problem, cause_arrow_x, cause_arrow_y, top=top_row) |
| 187 | + |
| 188 | + |
| 189 | +# Input data |
| 190 | +categories = { |
| 191 | + 'Method': ['Time consumption', 'Cost', 'Procedures', 'Inefficient process', |
| 192 | + 'Sampling'], |
| 193 | + 'Machine': ['Faulty equipment', 'Compatibility'], |
| 194 | + 'Material': ['Poor-quality input', 'Raw materials', 'Supplier', |
| 195 | + 'Shortage'], |
| 196 | + 'Measurement': ['Calibration', 'Performance', 'Wrong measurements'], |
| 197 | + 'Environment': ['Bad conditions'], |
| 198 | + 'People': ['Lack of training', 'Managers', 'Labor shortage', |
| 199 | + 'Procedures', 'Sales strategy'] |
| 200 | +} |
| 201 | + |
| 202 | +draw_body(categories) |
| 203 | +plt.show() |
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