Bar graphs and line graphs are two different ways of visualizing data. Both bar and line graphs use vertical and horizontal axes to display values, but they do so in different ways.
Bar graph
A bar graph is a rectangular block of data with varying heights depending on the value it represents. Bar graphs can be used to represent anything you fit into categories, including height, weight, sales, or any other numerical value.
For example, if you were to look at a bar graph showing how many people in different countries speak French as their first language, the height of each rectangle would represent the number of people who speak French as their first language in that country.
Line graph
A line graph is a type of graph that uses a line or lines to illustrate data. A line graph is useful because it allows you to visualize the relationship between two variables over time or space. For example, if you have data on the number of people who have visited your website each month, you can plot that data on a line graph over time and see how it changes over time.
A line graph uses lines to represent data points instead of points themselves. Each point represents one piece of information; however, depending on how many points are plotted, there may be too much information for the eye to process at once. A line graph helps us visualize trends in our data by smoothing out these individual points into continuous lines that imply a trend over time or at least over some quantity that increases sequentially.
How do you combine a bar and line graph?
Here's a step-by-step guide on how to do this in a tool like Microsoft Excel:
- Prepare your data: Ensure you have all the data you want to plot on the graph. Typically, this would be in a table format with rows and columns.
- Insert a chart: Go to the "Insert" tab, and click on "Chart". For the first data set, you might choose a bar chart (Column Chart in Excel).
- Add your data: Select the data you want for the bar graph (usually, this will be categorical data or time periods on the x-axis and the corresponding values on the y-axis). This will create the bar graph.
- Add a second series: You'll need to add the data for the line graph. In Excel, you can do this by right-clicking on the chart, choosing "Select Data", and then "Add" to include the second set of data.
- Change the second series to a line chart: Right-click on the new series you just added (which will initially also be a bar chart), select "Change Series Chart Type", and then choose the Line Chart option. This will turn the second series into a line chart on the same graph as the bar chart.
- Format your chart: From here, you can add titles, label your axes, adjust the scales, and customize the colors and styles as needed.
By following these steps, you can create a combo chart that uses both a bar and a line graph to present different but related data sets. This can be particularly useful when you want to compare and contrast these data sets in a single visualization.
What is the difference between a bar graph and a line graph?
Both bar graphs and line graphs are types of data visualization tools that are used to display and compare data, but they're often used in different scenarios and convey different types of information. Here are some key differences:
1. Type of Data:
- Bar graphs are typically used to compare quantities of different categories in data. They are great for comparing categorical or nominal data where the categories are distinct and don't overlap. For example, comparing the population of different countries, the sales of different products, etc.
- Line graphs, on the other hand, are used to show a trend over time, also known as a time series. They are best used for continuous data, especially when it's important to represent the changes in the data over time. For example, showing how a stock price has changed over the past year, tracking temperature changes over a week, etc.
2. Presentation of Data:
- In a bar graph, data is represented by rectangular bars where the length of the bar is proportional to the quantity of the data. Each bar represents a different category of data.
- In a line graph, data points are plotted on a graph and then connected by a line to show a trend or change over time. The individual points represent the data at different periods in time.
3. Comparison and Trends:
- Bar graphs make it easy to compare data between different groups. Each bar stands alone, so it's straightforward to see which categories are larger or smaller.
- Line graphs are better at showing trends and patterns in data over time. By connecting the data points, it's easy to see if something is increasing, decreasing, or staying the same over time.
4. Use of Axes:
- In bar graphs, the x-axis represents different categories of data, while the y-axis represents the quantity or frequency of those categories.
- In line graphs, the x-axis often represents time, while the y-axis represents the quantity being measured over time.
In general, whether you use a bar graph or a line graph depends on what kind of data you're working with and what you want to illustrate about that data.
Types of Graphical Representation
- Bar Graph: This uses either horizontal or vertical bars to categorize and compare different quantities. The length or height of the bar corresponds to the value it represents.
- Pie Chart: This represents data in the form of slices of a circle, where each slice represents a category. The size of each slice is proportional to the category it represents.
- Line Graph: This shows trends over time by connecting data points with straight lines. It's especially useful for showing changes over a period and trends.
- Pictograph: This type of graph uses pictures or icons to represent data values. Each image or icon represents a specific number or quantity, allowing for an easy-to-understand visual comparison.
- Histogram: This is a type of bar graph used to display frequency data. The bars are adjacent to each other, indicating that the data is in intervals.
- Frequency Distribution: This graphical representation (usually a table or a graph) shows how often each different value in a set of data occurs.
- Stem and Leaf Plot: This method of data representation organizes data into a semi-graphical representation that can display large amounts of data, and allows you to see the distribution and shape of the data set.
- Scatter Plot: This is used for displaying values for two variables for a set of data. The data is displayed as a collection of points, each representing the value variables plotted on a horizontal and vertical axes.
Each type of graphical representation has its own strengths and can be used in different situations depending on the data you're working with and what you want to communicate. It's important to understand each one in order to choose the best method for your specific needs. Several tools, such as Mokkup.ai, empower users to generate wireframes for dashboards and facilitate the creation of final designs for implementation.
When to use a bar graph
It is best used to compare data that can be classified into categories like age, gender, race, or income. The bars in a bar graph represent the frequency of each category and are placed on a scale starting from the bottom and moving up. The height of each bar represents the amount of data in that category.
The main purpose of using a bar graph is to help you understand how your data is distributed across different categories. For example, if you're looking at sales data for a company's products over time, then you may want to see how much each product contributed to overall sales. Bar graphs are also great for representing percentages within a given period of time; for example, if sales increased by 5% over last year, then you could use a bar graph to show this change over time as well as other changes within your business's financial statements such as profits/losses and assets/liabilities.
When to use a line graph
Line graphs are great for showing changes over time, and even small changes can be easily spotted on a line graph. Line graphs are also useful for comparing data from different sets, as all the data points will be on the same scale.
For example, consider profits generated by a store over time. If you were to plot these profits on a bar graph, you would need to make your categories smaller as the time intervals get shorter (to avoid having one bar cover multiple bars). However, when you use a line graph, you can compare all of your data points using the same scale (as shown below).
Conclusion
In conclusion, both bar and line charts are useful for visualizing data. The choice of chart type depends on the data being represented and the message that you want your audience to understand. Line charts are best when you need to show even small differences in values or trends, while bar graphs are better at showing large differences between data points. Use Mokkup.ai to experiment with multiple graphs and various elements, enabling you to determine which ones best meet your specific requirements.