This topic describes how to create a project in DataV to view air quality changes before and after the Spring Festival.
Spatial interpolation is generally used to convert scattered data into consecutive data on a curve to compare the data with data in other distribution modes.
That is, the data obtained from existing monitoring sites can be used to estimate data of other locations. Then, colors are mapped according to the value range and an isothermal map is generated.
This widget supports callback IDs, which can be used to connect this widget to other widgets. Data of connected widgets will be automatically updated when the time on the timeline changes.
If a correct callback ID is set, the system will trigger a data request when time changes and automatically adds the callback ID and the value of the callback ID to the parameter list of the corresponding APIs of other widgets.
- IP address of the initial API: http://127.0.0.1:8888/aqi
- IP address of the API after callback is triggered: http://127.0.0.1:8888/aqi?date=2017012722
The callback ID is
The callback ID supports SQL statements. To use the callback ID, you need to use a colon (
:) and the callback ID name in your SQL statements.
- Initial SQL statement:
select :date as value;
- SQL statement after callback is triggered:
select '2017022722' as value;