No dependencies
To create a Gantt chart that has no dependencies, make sure that the last value for each row in your DataTable is set to null.
Grouping resources
Tasks that are similar in nature can be grouped together using resources. Add a column of type string to your data (after the Task ID and Task Name columns), and make sure any tasks that should be grouped into a resource have the same resource ID. Resources will be grouped by color.
Computing start/end/duration
Gantt charts accept three values relating to the duration of the task: a start date, an end date, and a duration (in milliseconds). If, for example, there is no start date, the chart can calculate the missing time based on the end date and the duration. The same goes for calculating the end date. If both the start and end date are given, the duration can be calculated between the two.
See the below table for a list of how Gantt handles the presence of start, end, and duration in different circumstances.
Critical path
The critical path in a Gantt chart is the path, or paths, that directly affect the finish date. The critical path in Google Gantt charts is colored red by default, and can be customized using the criticalPathStyle options. You can also turn off the critical path by setting criticalPathEnabled to false.
Styling arrows
You can style the dependency arrows between tasks with the gantt.arrow options:
Styling tracks
Grid styling is handled by a combination of innerGridHorizLine, innerGridTrack, and innerGridDarkTrack. By setting only the innerGridTrack, the chart will calculate a darker color for the innerGridDarkTrack, but by setting only the innerGridDarkTrack, the innerGridTrack will use its default color and will not calculate a lighter color.
Data format
Rows: Each row in the table represents a task.