Google Earth Engine(GEE)——EVI指数迭代计算和随时间序列累计值的求取！

很多人在对比未来的影像evi或者ndvi或者其他指数和之前一些年份的均值，并以累计值的形式来呈现，所以本次就从这里出发，最后给出一个累计值的效应，而且是按照逐年逐月，如果不进行累加的话，最后的结果应该呈现一个比较稳定的周期性循环波动，具体可以看后面的结果呈现。

本篇需要用到的函数：

Chart.image.series(imageCollection, region, reducer, scale, xProperty)

这个比较简单我就不过多解释了。

DEPRECATED: Use ui.Chart.* instead.

Generates a Chart from an ImageCollection. Plots derived values of each band in a region across images. Usually a time series.

- X-axis: Image, labeled by xProperty value.

- Y-axis: Band value.

- Series: Band names.

Returns a Chart object that can be passed to print().

Arguments:

imageCollection (ImageCollection):

An ImageCollection with data to be included in the chart.

region (Feature|FeatureCollection|Geometry):

The region to reduce.

reducer (Reducer, optional):