Neelgagan | Graph Note Book | Jumbo | Pages: 52 |

• Pie chart – A pie chart represents the data in groups. The entire pie chart is split into slices according to the percentage of values. Pie charts are used when the number of groups are small, around 6 groups or less.
• Bar graph – A bar graph is plotted using horizontal and vertical columns. The greater the length of the bars the higher values they represent. Example, the increase in the crop production each year. Generally, bar graphs are used when the differences between categories are larger.
• Line graph – A line graph is like a scatter plot except that it makes use of a continuous variable, such as time, temperature, height, and weight along the X-axis. For example, the increase in weight of a person over weeks. Line graphs are preferred over bar graphs when the differences between categories are small.
• Scatter plot – A scatter plot is generally used to explain the dependence/correlation between two variables. For example, the relationship between average rainfall and crop yields.

Understanding such complicated graphs poses a huge challenge for the visually impaired. The widely used method for this is relying on a screen reader to read aloud the text. At times, this can be quite difficult in case of complicated graphs and even 3D graphs. Broadly, alt text for any kind of graph should include the title of the graph, the type of graph, information regarding the X- and Y-axis, and the trend/information the graph is used to convey. A proper understanding of the data set and the purpose of the graph is a prerequisite for a person providing alternate text for graphs. For example,