GEE开发之MODIS_NDVI年均值数据分析

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代码如下（以鹿邑县为例）：

var geometry = ee.FeatureCollection('users/www1573979951/luyixian');
// 选择数据集并进行波段比例换算
var collection = ee.ImageCollection("MODIS/006/MOD13Q1").filterDate('2000-01-01', '2020-12-31').select("NDVI");
//换算单位
var multiply = function(image){ 
  var img = image.multiply(0.0001);  
  return img.set(image.toDictionary(image.propertyNames()));
};
collection = collection.map(multiply);


//进行年平均值的计算
var years = ee.List.sequence(2000, 2020);
var collectYear = ee.ImageCollection(years
  .map(function(y) {
    var start = ee.Date.fromYMD(y, 1, 1);
    var end = start.advance(12, 'month');
    return collection.filterDate(start, end).reduce(ee.Reducer.mean()).float().set('system:time_start',y).set('year',y);
}));
print(collectYear);

//年均值的时间序列展示
var Yearly_chart = ui.Chart.image.series({
    imageCollection: collectYear.select('NDVI_mean'),
    region: geometry,
    reducer: ee.Reducer.mean(),
    scale: 500,
    xProperty: 'year',
    }).setOptions({
      interpolateNulls: true,
      lineWidth: 2,
      title: 'NDVI Yearly Seires',
      vAxis: {title: 'NDVI'},
      hAxis: {title: 'Date'},
      //trendlines: { 0: {title: 'NDVI_trend',type:'linear', showR2: true,  color:'red', visibleInLegend: true}}
    });
print(Yearly_chart);

数据集截图：

数据表格趋势截图

CSV数据：