//加载中国边界
var china = pie.FeatureCollection("RESDC/WORLD_COUNTRY_BOUNDARY")
               .filter(pie.Filter.eq("name", "CHINA"))
               .first()
               .geometry();
//加载中国30m精细地表覆盖产品数据
var img = pie.ImageCollection('CAS/GLC_FCS30_2020')
             .filterBounds(china)
             .select("B1")
             .mosaic()
             .clip(china);
print(img);
//设定预览参数
visParams = {
    uniqueValue: ['10', '11', '12', '20', '51', '52', '61', '62', '71', '72', '81',
                  '82', '91', '92', '120', '121', '122', '130', '140', '150', '152',
                  '153', '180', '190', '200', '201', '202', '210', '220', '250'],
    palette: ['FFFF64', 'FFFF64', 'FFFF00', 'AAF0F0', '4C7300',
              '006400', '00A000', 'AAC800', '003C00', '005000',
              '285000', '286400', 'A0B432', '788200', '966400',
              '964B00', '966400', 'FFB432', 'FFDCD2', 'FFEBAF',
              'FFD278', 'FFEBAF', '00DC82', 'C31400', 'FFF5D7',
              'DCDCDC', 'FFF5D7', '0046C8', 'FFFFFF', 'FFFFFF']
};
//加载显示影像
Map.centerObject(china, 2);
Map.addLayer(img, visParams, "地表覆盖");
// 图例
var data = {
    title: "地表覆盖",
    colors: ['#FFFF64', '#FFFF64', '#FFFF00', '#AAF0F0', '#4C7300',
             '#006400', '#00A000', '#AAC800', '#003C00', '#005000',
             '#285000', '#286400', '#A0B432', '#788200', '#966400',
             '#964B00', '#966400', '#FFB432', '#FFDCD2', '#FFEBAF',
             '#FFD278', '#FFEBAF', '#00DC82', '#C31400', '#FFF5D7',
             '#DCDCDC', '#FFF5D7', '#0046C8', '#FFFFFF', '#FFFFFF'],
    labels: ["旱作农田", "草本覆盖", "乔木或灌木覆盖(果园)", "灌溉农田", "开阔的常绿阔叶林",
             "封闭的常绿阔叶林", "开阔的落叶阔叶林", "封闭的落叶阔叶林", "开阔的常绿针叶林",
             "封闭的常绿针叶林", "开阔的落叶针叶林", "封闭的落叶针叶林", "开阔的混叶林",
             "封闭的混叶林", "灌木", "常青灌木", "落叶灌木", "草地", "地衣和苔藓",
             "稀疏植被", "稀疏灌木", "稀疏草本", "湿地", "不透水面", "裸地",
             "牢固的裸地", "松散的裸地", "水体", "永久冰雪", "其他"],
    step: 1
};
var style = {
    left: "20%",
    top: "60%",
    height: "130px",
    width: "1200px"
};
var legend = ui.Legend(data, style);
Map.addUI(legend);