PIE-Engine監(jiān)督分類 代碼：

//?定義研究區(qū)域：

var?geometry?=?pie.FeatureCollection("user/3069305918@qq.com/Dandinghe")

??????????????????.first()

??????????????????.geometry();

Map.addLayer(geometry,?{?color:?"ff0000ff",?fillColor:?"00000000"?},?"分析區(qū)域");

Map.centerObject(geometry,?10);//把研究區(qū)域矢量圖放在中心，并使用10級縮放：

//?篩選數(shù)據(jù)：

var?image?=??pie.ImageCollection("GF1/L1A/WFV_SR")//選擇數(shù)據(jù)源為高分一號數(shù)據(jù)

//?var?image?=??pie.ImageCollection("S2/L2A")//選擇數(shù)據(jù)源為高分一號數(shù)據(jù)

???????????????????.filterBounds(geometry)//以roi邊界為位置選擇影像

???????????????????.filterDate("2019-5-1","2019-10-31")//選擇在2019年的影像

???????????????????.select(["B4","B3","B2"])//選擇需要的波段

???????????????????.mosaic()//選擇需要的波段并拼接影像

???????????????????.multiply(10000)

???????????????????.clip(geometry);//按照研究區(qū)域裁剪影像

//?Map.addLayer(image.select(["B4","B3","B2"]),{min:0,max:5000,opacity:0.6},"假彩色影像image",true);

//?print(image)

//?導(dǎo)出矢量要素：

//?Export.table({

//???collection:?geometry0,

//???description:?"ExportShp"

//?});

//?加載位置點要素（點要素帶有位置，以及標(biāo)注好的landcover字段，用于分類）：

var?points?=?pie.FeatureCollection('user/3069305918@qq.com/DDH_points');//?DDH_points點集合中：landcover從1~5表示四種不同地物類型

print("roi:",?points)

//?Map.addLayer(points,?{?color:?'FF0000',?fillColor:?'00000000',?width:?2?},?"points");

//在點矢量points處對遙感影像image以10m比例尺進(jìn)行采樣，攜帶字段landcover，得到初始總樣本training？

var?training?=?image.sampleRegions(points,?["landcover"],?10,?"",?"",?true);//?.sampleRegions():從Image中隨機(jī)采樣，返回FeatureCollection類型

print("training:",?training)

Map.addLayer(training,?{?color:?'FF0000',?fillColor:?'00000000',?width:?2?},?"training");

//?//?將獲得的總樣本按照7:3分成訓(xùn)練樣本和驗證樣本

var?withRandom?=?training.randomColumn('random');//添加"random"字段并賦0~1的偽隨機(jī)數(shù)

var?trainPartition?=?withRandom.filter(pie.Filter.lte("random",?0.7));//取70%為樣本點

var?testPartition?=?withRandom.filter(pie.Filter.gt("random",?0.7));//取30%為驗證點

Map.addLayer(withRandom,?{?color:?"yellow"?},?"withRandom");

Map.addLayer(trainPartition,?{?color:?"red"?},?"trainPartition");

Map.addLayer(testPartition,?{?color:?"blue"?},?"validation");

print("withRandom",?withRandom);

print("trainPartition",?trainPartition);

print("validation",?testPartition);

//?定義SVM參數(shù)

var?options?=?{

????//?SVM類型:?C_SVC=100,NU_SVC=101,ONE_CLASS=102,EPS_SVR=103,N-U_SVR=104

????"svmType":?100,

????//?SVN核類型：LINEAR=0,POLY=1,RBF=2,SIGMOID=3,CHI2=4,INTER=5

????"kernelType":?0,

????//?核函數(shù)的γ參數(shù)，默認(rèn)值為1；

????"gamma":?1,

????//?核函數(shù)的coef0參數(shù)，默認(rèn)值為0

????"coef0":?0,

????//?多項式核函數(shù)的degreee參數(shù)（階數(shù)），默認(rèn)值為0；

????"degree":?0,

????//?用最優(yōu)參數(shù)訓(xùn)練SVM，如果是會相當(dāng)耗時

????"trainAuto":?0,

????//?迭代終止方式：1表示最大迭代次數(shù)?2表示最小收斂閾值?3表示最大迭代次數(shù)和最小收斂閾值組合

????"type":?3,

????//?最小收斂的閾值：當(dāng)點之間的距離小于這個值的時候終止迭代

????"minDistance":?0.1,

????//?最大的迭代次數(shù)：計算多少次終止聚類迭代

????"maxIter":?100

};

//分類器進(jìn)行分類

var?classifer?=?pie.Classifier.svm(options).train(trainPartition,?"landcover",?["B4",?"B3",?"B2"]);

var?resultImage?=?image.classify(classifer,?"classify_handa");

print("resultImage:",?resultImage);

//?分類后處理：平滑影像，進(jìn)行開閉運(yùn)算剔除噪聲影響.

var?resultImage2?=?resultImage.focal_min(2).focal_max(2);

//?var?kernel=?pie.Kernel().mean(3)

//?class_image2?=?resultImage.convolve(kernel)

var?visParam?=?{

????opacity:?1,

????uniqueValue:?'1,2,3,4,5',

????palette:?'467EDA,EC632B,CCDC45,55B548,F5AB20'

};

Map.addLayer(resultImage,?visParam,?'分類結(jié)果');

Map.addLayer(resultImage2,?visParam,?'平滑處理后結(jié)果');

//6.精度驗證

var?matrix?=?classifer.confusionMatrix();

print("matrix",?matrix);

//?評估訓(xùn)練樣本的精度.

var?checkM?=?classifer.confusionMatrix();

print("訓(xùn)練矩陣-ACC系數(shù)：",?checkM.acc());

print("訓(xùn)練矩陣-Kappa系數(shù)：",?checkM.kappa());

//?評估驗證樣本的精度.

var?predictResult?=?testPartition.classify(classifer,?"classification");

var?errorM?=?predictResult.errorMatrix("landcover",?"classification");

print("驗證矩陣-ACC系數(shù)：",?errorM.acc());

print("驗證矩陣-Kappa系數(shù)：",?errorM.kappa());

//?添加圖例

var?data?=?{

????title:?"分類結(jié)果",

????colors:?['467EDA','EC632B','CCDC45','55B548','F5AB20'],

????labels:?["1-水域",?"2-水田",?"3-草地",?"4-林地","5-灘涂"],

????step:?1

};

var?style?=?{

????right:?"100px",

????bottom:?"10px",

????height:?"70px",

????width:?"300px"

};

var?legend?=?ui.Legend(data,?style);

Map.addUI(legend);