简介：
在GEE中实现时序图像的加载主要的目的是查看影像波段或者指数的变化，这里我们使用的主要是加载常规的4个波段，然后添加一个复合波段，复合波段主要的是求4个波段的平均值，然后再次加入到原有的4个波段的时序图中。这里面主要的技术难点一个是图表的设定，另外一个就是如何加入新的波段到图表中并展示出来。
函数：
ui.Chart.image.series(imageCollection, region, reducer, scale, xProperty)
Generates a Chart from an ImageCollection. Plots derived values of each band in a region across images. Usually a time series.
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X-axis: Image, labeled by xProperty value.
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Y-axis: Band value.
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Series: Band names.
Returns a chart.
Arguments:
imageCollection (ImageCollection):
An ImageCollection with data to be included in the chart.
region (Feature|FeatureCollection|Geometry):
The region to reduce.
reducer (Reducer, optional):
Reducer that generates the valu