# Tableau Visualisation-All you want to know about Bar Chart

Bar charts are one of the many techniques used **to present data in a visual form so that the reader may readily recognize patterns or trends**. Bar charts usually represent categorical variables, discrete variables or continuous variables grouped in class intervals.

**Based on the structure of the bars and the number of parameters, the bar graph is classified into the following six types.**

**Types of Bar Chart**

Vertical bar graph.

Horizontal bar graph.

Segmented bar graph

Stacked bar graph.

Double bar graph (Grouped bar graph)

Multiple bar graph (Grouped bar graph)

Dual Axis Bar chart.

Bar line graph.

**Vertical Bar chart **

A bar chart or bar graph is a chart or graph that presents categorical data with rectangular bars with heights or lengths proportional to the values that they represent. The bars can be plotted vertically . A vertical bar chart is sometimes called a column chart.

Segment comes in Columns in the vertical chart and SUM(Sales) in rows

That is if measure comes in rows and Dimension comes in column we get vertical chart.

**Horizontal Bar chart**

In this type of Bar chart, the bars will be horizontal . SUM(Sales) dragged to Columns and Segment comes in Rows.Here Measure dragged to Columns and Dimension dragged to Rows.

**Segmented Bar chart**

Segmented Bar charts are one of the most popular charts used in Statistics. They are a type of stacked bar chart.

A *segmented bar chart* are used to compare two or more categories by using vertical or horizontal bars.

Drag **Segment** to color in the Marks card.

**SUM(Sales) **in the rows to get segmented bar chart of the above bar chart.

Blue stands for Consumer

Orange stands for Corporate

Red stands for Home Office

While a bar graph represents the frequencies of categories of one variable, a stacked (segmented) bar graph represents the frequencies of combinations of categories of two variables.

**Stacked Bar chart**

A stacked chart is a form of bar chart that shows the composition and comparison of a few variables, either relative or absolute, over time. Also called a stacked bar or column chart, they look like a series of columns or bars that are stacked on top of each other.When data points are stacked on top of each other, the percentage of each data point may be compared to the overall value.

Steps to make a stacked bar chart

Drag YEAR(Order Date) to column.

Drag and drop measure names to Marks and filter.

Drag measure values to rows(which consists of profit and sales).Here we have filtered out every other field and taken Profit and Sales.You can select any number of measure values

Profit in Red,Sales in blue color.

We can see percentage of Profit and Sales compared to overall value

**Double Bar Graph**

This is a graphical representation of information using two bars besides each other at various Heights. Bars can be vertical or horizontal.We can use double bar graph to compare two data groups.The

X axis of double bar graph shows categories to be compared.The Y axis represents scale, scale is a set of numbers that organize data into equal interval.Here X axis is Male/Female that is selected based on the calculated field which is dragged to Columns and Y axis is Count of patients.This chart is a comparison of Male and Female sepsis patients.You can see Legend on right side, Blue is for Female and Orange is for Male.

**Grouped Bar chart**- also known as side-by-side bar charts.

A grouped bar chart is used when you want to look at how the second category variable changes within each level of the first, or when you want to look at how the first category variable changes across levels of the second. We’ll call comparisons of the first type “within-group” comparisons, and comparisons of the second type “between-group”.

This is a Side by side chart which shows O2Sat Level of patients(calculated field for finding O2Sat Level) in the Columns and count of patients in the rows.

You can see filter of O2sat calculated field, null values are filtered out.

From this chart we can see O2Sat level normal level there are highest number of patients,then mild level is the second highest no of patients.

**Dual Axis Chart**

As the name mentions this is a chart consisting of two axes on both the Left and Right side of the chart.

** Example**

Figure: Left Axis is Avg Heart Rate and Right Axis is Avg O2Sat

**Note:- **Here i have chosen bar chart,any type of chart we can do Dual Axis

Inorder to make a Dual Axis chart you need two measures in row.Here I have dragged O2Sat and HR to row and right click select average for both.Click on second /Rightmost measure-O2Sat in Rows-You get drop-down, select Dual Axis

as shown in the left picture.

**To Synchronise the Axis of chart**

**Right click on right axis (**that is O2Sat axis) -Select **Edit Axis-**Select Synchronise Axis(Click the Tick mark) as shown in the picture on the right

This visualisation was to find the relation of Heart Rate and Oxygen saturation level of sepsis patients.Rapid heart rate is one of the early symptoms of sepsis.As HR decreases O2Sat level increases(which means O2Sat coming to normal range). It is evident that with this kind of visualisation,we can compare both the values using Dual Axis chart.

A dual axis chart is used to present the relationship between two variables. More specifically, these charts are useful for demonstrating the relationship between two or more measures with different amplitude and scale

**Bar-Line charts **

Bar-Line charts show two metric values aggregated across a group dimension. They are useful for showing quantity alongside changes in trends over time. The first Y-axis metric displays as a bar, and the second displays as a line.

In this example we are taking one measure Sales and Measure values

-consisting of all measures.We filter Profit and Quantity in that.

SUM(Sales) is represented by bar chart and Profit and Quantity represented by two Line charts.

Here Bar and Line chart comes together hence the name, **Bar- Line chart.**

Line charts are ideal for showing changing time series as well as trends and developments over time. Bar charts are **good for comparing size, especially on small screens**.

**Advantages of Bar Chart**

show each data category in a frequency distribution.

display relative numbers or proportions of multiple categories.

summarize a large data set in visual form.

clarify trends better than do tables.

estimate key values at a glance.

permit a visual check of the accuracy and reasonableness of calculations.

**DisAdvantage of Bar Chart**

It displays each category of data in a frequency distribution. It fails to reveal key assumptions, causes, effects, or patterns.

Hope you all got a good understanding about the different types of Bar charts.

**Happy Learning!!!**