Overview
Application Scenario
The flow map displays the movement and quantity of information items or objects from one location to another on the map. You can use it to demonstrate the migration data of persons, animals, and products.
The scale or quantity of each movement is represented by the thickness of each flow line, which helps to display the geographic distribution of migration.
Flow maps are widely used to display interregional trades, traffic flow, population migration, shopping behavior, communication information flow, and air routes. They can also be applied to enterprise cargo transportation and supply chain management.
For example, the following figure shows the migration routes during Spring Festival in China.
Basic Requirement
| Chart Effect | Field |
|---|---|
Flow map | Two geographic dimensions and one indicator |
Chart Feature
Advantage: It's suitable for displaying the changes in data corresponding to the movement of objects within a geographic space.
Disadvantage: It is not suitable for displaying precise data.
Example 1: Flow Map of Two Points
Data Description
The following table lists some necessary fields for a flow map.
Field | Description |
Geographic field | For example, you can obtain the longitude and latitude dimensions of City when you convert City to a geographic role. In addition, you can also create a map through latitude and longitude data. For details, see Converting Indicator Fields into Geographical Roles. |
Migration route | Two cities form a migration route, such as Nanjing and Sanya form Nanjing City-Sanya City, and Nanjing and Zhongwei form Nanjing City-Zhongwei City. |
Sequence Number | Cities are connected in a flowline by the sequence number in the ascending order. For example, if the sequence numbers of Nanjing and Sanya are 0 and 1 respectively, the route Nanjing City-Sanya City is formed from Nanjing to Sanya. |
The following figure shows an example of the field data format for flow maps.
Data Processing
Generally, the data you obtain needs to contain Source and Destination. So, you should process the data first to get the required flow map data.
Data Upload
1. Log in to FineBI, click My Analysis, select a folder, and click New Subject.
2. Click Local Excel and click Upload Data, as shown in the following figure.
You can download Tourism Statistics.xlsx.
3. Click OK after the data is uploaded, as shown in the following figure.
Adding Migrant Routes
Click Formula Column, name the added formula column Migrant Route, and enter the formula ${Source}+"-"+${Destination}.
Using Column to Row and Assignment Column to Create Sequence Number Fields
1. Choose More > Column to Row, select Source and Destination, and click OK.
2. Click Assignment Column and name the column Sequence Number.
Select Column Field from Assignment Basis to assign the value 0 to Source and 1 to Destination.
Field Setting
Choose More > Field Settings, rename Value Field to City, adjust the format of Sequence Number to Value, and hide Column Field.
Now you can click Save and Update and then Exit and Preview.
Creating Your Flow Map
Converting Fields into Geographic Roles
1. Click Component in the lower left corner, as shown in the following figure.
2. Since the map component needs geographic fields, choose City > Geographic Role > City, and finish the region match. Click OK.
Designing Your Flow Map
1. Click Flow Map, drag City (Longitude) to Horizontal Axis, City (Latitude) to Vertical Axis, Sequence Number to Connection, and Migrant Route and City to Fine-grained.
Note:
2. Drag Migrant Quantity to Color and change Gradient Solution to Aurora to reflect the quantitative distinction through the color of lines.
Beautifying Your Flow Map
Setting Connection
Click Connection, set Curve to Style, and select No from Mark Point.
Setting Flashing Animation
1. Select Special Display > Flashing Animation from Sequence Number in Connection.
2. Click Add, set Time Interval to 8 seconds, and click OK.
Hiding Legends
Deselect Display All Legends under Component style > Legend.
Customizing GIS Background
Click Background, and change the GIS background to Blue.
Effect Display
Example 2: Flow Map of More Than Two Points
Description
You can download High-speed Railway Road Section Table.xlsx.
The following lists some necessary fields for a flow map.
Geographic Fields: such as Longitude and Latitude in the following figure.
Note:
Migration Route: such as from Nanjing to Hangzhou, from Hangzhou to Ningbo, and from Ningbo to Shenzhen
Numbering: It displays the connection sequence from small to large. For example, Nanjing is 0, and Hangzhou is 1, so the route Nanjing-Hangzhou is formed from Nanjing to Hangzhou.
Adding Data
Add data through steps that are the same as section "Data Processing."
Note:Modify the field types of Sequence Number as Text before clicking OK.
Creating Your Flow Map
Adding Components
Click Component in the lower left corner.
Converting Fields into Geographic Roles
1. Choose Longitude > Geographic Role > Longitude.
2. Choose Latitude > Geographic Role > Latitude.
Designing Your Flow Map
1. Click Flow Map, drag Longitude to Horizontal Axis, Latitude to Vertical Axis, Sequence Number to Connection, and Route to Fine-grained.
2. Drag Length to Color, and set Gradient Solution as Colorful.
3. Select Flashing Animation under Length in Color.
4. Set the thickness of lines.
Effect Display
