Change the label of the ui.Chart.image.seriesByRegion in Google Earth Engine

How do I make a chart in Google Earth Engine?

Use the ui. Chart. setChartType() method to set chart type. Each page linked to in the Earth Engine object charts and DataTable charts sections include examples for generating several chart types.
 

What is feature collection in Google Earth Engine?

Groups of related features can be combined into a FeatureCollection , to enable additional operations on the entire set such as filtering, sorting and rendering. Besides just simple features (geometry + properties), feature collections can also contain other collections.