PIE-Engine 教程:水稻面积提取2—监督分类(宿迁市)

/**
 * @Name    :   基于 PIE Engine Studio 的水稻自动提取
 * @Author  :   武汉大学VHR队
 * @Desc    :   淮安市水稻提取 - 进行监督分类
 * @Source  :   航天宏图第四届 “航天宏图杯”PIE软件二次开发大赛云开发组三等奖获奖作品
 */

//2.进行监督分类
var area = pie.Geometry.Polygon([
    [
        [
            118.19042604840365,
            32.717477656827796
        ],
        [
            119.67193792508522,
            32.717477656827796
        ],
        [
            119.67193792508522,
            34.12687250105918
        ],
        [
            118.19042604840365,
            34.12687250105918
        ],
        [
            118.19042604840365,
            32.717477656827796
        ]
    ]
], null);

//选择淮安市矢量
var roi = pie.FeatureCollection("NGCC/CHINA_CITY_BOUNDARY").filter(pie.Filter.eq('name', '淮安市')).first().geometry()
Map.centerObject(roi, 8)
Map.addLayer(roi)

//导入用于分类影像并勾选波段
var bands = ["B1", "B2", "B3", "B4", "B5", "B6", "B7", "B8", "B9"]
var l8Image = pie.Image('user/pieadmin/saas/06/l8Image_1320')
    .select(bands);

//合并样本点并采样
var sample = pie.FeatureCollection('user/pieadmin/saas/06/sample');
var sampleFeatureCollection = l8Image.sampleRegions(sample, ["type"], 30);
sampleFeatureCollection = sampleFeatureCollection.randomColumn('random');

//训练样本按0.7比例划分
var trainingFeatures = sampleFeatureCollection.filter(pie.Filter.lte("random", 0.7));
var testingFeatures = sampleFeatureCollection.filter(pie.Filter.gt("random", 0.7));

//随机森林或支持向量机分类
var classifier = pie.Classifier.svm().train(trainingFeatures, "type", bands); //支持向量机
//var classifier = pie.Classifier.rtrees().train(trainingFeatures, "type", bands); //随机森林

// 影像分类，并加载显示
var imageA = l8Image.classify(classifier, "classifyA");
var visParam = {
    min: 1,
    max: 4,
    palette: 'EAF2F5,000032,1F3600,FAFFC8'
};
Map.addLayer(imageA, visParam, "ClassifyImage");

// 添加图例  
var data = {
    title: "淮安市水稻分类",
    colors: ['#EAF2F5', '#000032', '#1F3600', '#FAFFC8'],
    labels: ["水稻", "其他植被", "城镇", "水体"],
    step: 1
};
var style = {
    bottom: "10px",
    right: "450px",
    width: "350px",
    height: "70px"
};
var legend = ui.Legend(data, style);
Map.addUI(legend);

//导出随机森林或支持向量机分类结果
Export.image({
    image: imageA,
    description: "svmImage",
    assetId: "svm",
    region: area,
    scale: 30
});