In my (french) high school, we were taught to insert an axis break symbol in line graphs when necessary. See the figure labeled "Indicating a y-axis break" here

In my (french) high school, we were taught to insert an axis break symbol in line graphs when necessary. See the figure labeled "Indicating a y-axis break" here: https://en.wikipedia.org/wiki/Misleading_graph#Truncated_graph https://en.wikipedia.org/wiki/Misleading_graph#Truncated_gra...