Data Visualization — introduction of Tableau

From my perspective, either a data scientist or a data analyst is supposed to be excellent at not only digging in the data with fancy models or statistics skills, but also telling stories to describe what you find. Fortunately, there are many available tools, such as tableau and Power BI, that could help achieve that. Let’s start with introduction of tableau. Before we start, I hope you have downloaded and installed Tableau Desktop, an amazing software that visualizes your working with merely clicking and dropping.

There are four beginning-level parts you may use, including data preparation, map, dashboard and story. To better help you use them in a short time, I will show it with some fake sales data to explain. By the way, tableau could get data from a bunch of data sources, such as excel/csv file, SQL databases, Json, Saleforce and etc.

Data Preparation

1, Cleaned with Data Interpreter

After load the data into tableau, you could review and modify data. A smart option, on the left-side bar, you could use to clean data: ’Cleaned with Data Interpreter’. With the help of data interpreter, it automatically fits data into tableau and creates a copy with both Key for the Data Interpreter and modified data. By the way, you could also modify data manually, such as changing columns’ names and filling in nan value.

click buttom ‘Cleaned with Data Interpreter’

2, linking another sheet

If you wants join another sheet based on some column, you could add more connections and drag another sheet to the blank. After you choosing which columns should be matched, two tables are joined easily. Besides, there are four ways to join, including inner join, left join, right join and outer join. Each option represent a way of data selection.

linking another sheet


Next, I will show how to show data in the world/United states map. Even if you do not have latitude or longitude data, you could generate a map to visualize data with clicks.

1, Generate latitude and longitude features automatically.

generate latitute and longitude

2,Generate a basic map

Then, You need to drag “latitude” to “Columns” and “Longitude” to “Rows”. After that, you need to click “show me” on the top right side and choose maps/symbol maps(shown as two types of map). If you state name is not recognized, you could see a grey left-side button named “unknown”. What you need to do is to click “edit location”and rename your states or choose Country/region in case you use foreign country’s map. Also, you could edit it under map options shown as below.

Two types of map

3, Make map setting

There are many options to choose. Let me use ‘Washout’ to set an example. Washout could only show the states/locations based on the data. As shown below, it conceals all countries except United states.

4, Present data

On the left side of Data field, there are names and values seperated by a line in ‘Table’ field.Next to the This field, it is called “Mask”. When you try to drag values into its options including color, label and etc, you could see the values shown on the map. Try to click these marks, you could figure out the best way to draw the map.

drag data into the map

A small tip when you draw the map. If you drag the Longtitude again on the columns, you could get the other map to compare. For me, It is convenient to figure out a better solution.

Compare maps

Data Engineer working in a telecommunication company; Passionate in data science; Enjoying sharing data skills

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