AI-generated Key Takeaways
-
ui.Chart.image.seriesByRegiongenerates a chart from an image collection, extracting and plotting a specified band's value for each region and image. -
The chart's x-axis represents images labeled by
xProperty(default: 'system:time_start'), the y-axis shows the reducer output, and series are regions labeled byseriesProperty(default: 'system:index'). -
This function is typically used to generate time series charts.
-
It takes an
imageCollection,regions,reducer, and optionalband,scale,xProperty, andseriesPropertyas arguments and returns aui.Chart. -
An example is provided demonstrating how to chart MODIS NDVI values over time for specified forest and urban regions.
- X-axis = Image labeled by xProperty (default: 'system:time_start').
- Y-axis = Reducer output.
- Series = Region labeled by seriesProperty (default: 'system:index').
Returns a chart.
| Usage | Returns |
|---|---|
ui.Chart.image.seriesByRegion(imageCollection, regions, reducer, band
, scale
, xProperty
, seriesProperty
)
|
ui.Chart |
| Argument | Type | Details |
|---|---|---|
imageCollection
|
ImageCollection | An ImageCollection with data to be included in the chart. |
regions
|
Feature|FeatureCollection|Geometry|List<Feature>|List<Geometry> | The regions to reduce. |
reducer
|
Reducer | Reducer that generates the value for the y-axis. Must return a single value. |
band
|
Number|String, optional | The band name to reduce using the reducer. Defaults to the first band. |
scale
|
Number, optional | Scale to use with the reducer in meters. |
xProperty
|
String, optional | Property to be used as the label for each image on the x-axis. Defaults to 'system:time_start'. |
seriesProperty
|
String, optional | Property of features in opt_regions to be used for series labels. Defaults to 'system:index'. |
Examples
Code Editor (JavaScript)
// Define regions of pixels to reduce and chart a time series for. var regions = ee . FeatureCollection ([ ee . Feature ( ee . Geometry . BBox ( - 121.916 , 37.130 , - 121.844 , 37.076 ), { label : 'Forest' }), ee . Feature ( ee . Geometry . BBox ( - 122.438 , 37.765 , - 122.396 , 37.800 ), { label : 'Urban' }) ]); // Define an image collection time series to chart, MODIS vegetation indices // in this case. var imgCol = ee . ImageCollection ( 'MODIS/006/MOD13A1' ) . filter ( ee . Filter . date ( '2015-01-01' , '2020-01-01' )) . select ([ 'NDVI' , 'EVI' ]); // Define the chart and print it to the console. var chart = ui . Chart . image . seriesByRegion ({ imageCollection : imgCol , band : 'NDVI' , regions : regions , reducer : ee . Reducer . mean (), scale : 500 , seriesProperty : 'label' , xProperty : 'system:time_start' }) . setOptions ({ title : 'Average NDVI Value by Date' , hAxis : { title : 'Date' , titleTextStyle : { italic : false , bold : true }}, vAxis : { title : 'NDVI (x1e4)' , titleTextStyle : { italic : false , bold : true } }, lineWidth : 5 , colors : [ '0f8755' , '808080' ], }); print ( chart );
