PIE-Engine APP:凉山州火灾高发地异常度分析系统-阿里云开发者社区

这里我们利用凉山州作为火灾边界，同样可以切换我们所需要的区域，可以切换省级代码来进行，需要手动修改。这里我们用到的swith 和case的案例条件判断分析，

语法

switch(n)
{
    case 1:
        执行代码块 1
        break;
    case 2:
        执行代码块 2
        break;
    default:
        与 case 1 和 case 2 不同时执行的代码
}

实例

显示今天的星期名称。请注意 Sunday=0, Monday=1, Tuesday=2, 等等：

var d=new Date().getDay(); 
switch (d) 
{ 
  case 0:x="今天是星期日"; 
  break; 
  case 1:x="今天是星期一"; 
  break; 
  case 2:x="今天是星期二"; 
  break; 
  case 3:x="今天是星期三"; 
  break; 
  case 4:x="今天是星期四"; 
  break; 
  case 5:x="今天是星期五"; 
  break; 
  case 6:x="今天是星期六"; 
  break; 
}

这里面所需的函数：

ui.DateSelect(type,placeholder,value,onChange,disabled,style)

时间选择。

方法参数：

- ui(ui)

调用者：ui对象。

- type(String)

- placeholder(String)

占位符内容。

- value(String|List)

选择具体的日期，格式为：yyyy-MM-dd|yyyy-MM-dd HH:mm:ss

- onChange(Function)

更新选择日期触发事件。

- disabled(Boolean)

是否禁用日期组件。

- style(Object)

组件样式。

返回值：ui.DateSelect

这里同样可以导出影像：

image(image,description,assetId,pyramidingPolicy,dimensions,region,scale,crs,crsTransform,maxPixels)

导出影像到个人存储空间。

方法参数：

- export(Export)

Export方法。

- image(Image)

要导出的影像。

- description(String, optional)

导出影像任务的描述。

- assetId(String, optional)

导出影像的存储路径。

- pyramidingPolicy(Object, optional)

金字塔规则。

- dimensions(Int, optional)

维度。

- region(Geometry, optional)

导出影像的范围。

- scale(Float, optional)

缩放比例，目前默认都是1。

- crs(Projection, optional)

投影的基准坐标参考系，暂指定为EPSG：4326或EPSG：3857参考系。

- crsTransform(List, optional)

投影坐标系变换值的列表。

- maxPixels(Long, optional)

要导出的最大像素数。

返回值：null

这个代码的还有提升的结果，如果要发布成为APP，那么就不太容易改变我们的研究区，因为在APP中没有code editor的界面，同样此APP的影像导出结果如果要下载，并没有出现在面板上。另外，对于chart图表的加载并没有加载到MAP上，如果转化为APP的化可能结果都无法显示，所以这个程序只能在code Editor界面中的控制台查看

代码：

/**
 * @Name    :   凉山州火灾高发地异常度分析系统
 * @Author  :   西南大学天生一队
 * @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
 */
//定义程序运行过程需要用到的变量
var date = ["2018-03-20", "2018-04-20"]; //开始日期和结束日期
var mapID = null; //当前图层ID
var maplegend = null; //当前图层图例ID
var roiID = null; //当前研究范围ID
var selectTag = "LST"; //选择的计算项目
var areaCode = "0"; //行政区划代码，默认为0
var roi = null; //研究区，在程序运行时动态变化
var default_roi = null; //默认研究区，凉山州
var sec_year = 2018; //要显示TVDI变化图的年份
var animationlayerID = []; //如果显示了动态图，则用此数组记录动态图的图层ID
var currentImg = null; //当前图层所对应的影像，导出时使用
var exportScale = 500; //导出分辨率
//获得凉山州矢量
roi = pie
  .FeatureCollection("NGCC/CHINA_CITY_BOUNDARY")
  .filter(pie.Filter.eq("name", "凉山彝族自治州"))
  .getAt(0)
  .geometry();
default_roi = roi; //将默认研究区设置为凉山彝族自治州
//设置渲染样式（默认拉伸渲染，参数为最小值为最大值）
function setVis(minvalue, maxvalue) {
  var newVis = {
    min: minvalue,
    max: maxvalue,
    palette: [
      "217303",
      "268303",
      "2a9203",
      "2fa203",
      "33b203",
      "37c203",
      "3bd203",
      "40e203",
      "44f203",
      "4bfc09",
      "56fd18",
      "6dfe37",
      "79fe47",
      "8cff05",
      "98ff04",
      "a5fe04",
      "b1fe03",
      "befe02",
      "cbfe02",
      "d7fd02",
      "e3fc02",
      "effb02",
      "faf802",
      "f9eb02",
      "f7dd03",
      "f6cf03",
      "f5c203",
      "f4b503",
      "f3a803",
      "f29b04",
      "f18e04",
      "f08104",
      "ef7404",
      "ee6804",
      "ed5b05",
      "ec4f05",
      "eb4305",
      "e93705",
      "e82b05",
      "e72006",
      "e61406",
      "e50906",
    ],
  };
  return newVis;
}
//按顺序输入影像集，起始时间、结束时间，要提取的波段名，研究区矢量【仅限单个波段提取】
function loadCol(nameCol, start, end, bandname, roi) {
  var rCol = pie
    .ImageCollection(nameCol)
    .filterDate(start, end)
    .filterBounds(roi)
    .select(bandname)
    .mean()
    .clip(roi);
  return rCol;
}
//更改行政区划后调用的函数
function getROI(code) {
  var new_roi = null;
  if (code !== 0) {
    var fCol = pie.FeatureCollection("NGCC/CHINA_PROVINCE_BOUNDARY");
    new_roi = fCol
      .filter(pie.Filter.eq("code", parseInt(code)))
      .first()
      .geometry();
  } else {
    new_roi = default_roi;
  }
  return new_roi;
}
//下载landsat8影像
function l8Col_load(start, end) {
  var l8Col = pie
    .ImageCollection("LC08/01/T1")
    .filterDate(start, end)
    .select(["B2", "B3", "B4", "B5", "B6", "BQA"])
    .filterBounds(roi)
    .map(function (image) {
      var qa = image.select("BQA");
      var cloudMask = qa.bitwiseAnd(1 << 3).eq(0);
      return image.updateMask(cloudMask);
    });
  return l8Col;
}
//定义Landsat8不同指数计算方式
var landsat8 = {
  //NDWI: (B03 - B05)/(B03 + B05)
  NDWI: function (image) {
    var b3 = image.select("B3");
    var b5 = image.select("B5");
    var ndvi = b3.subtract(b5).divide(b3.add(b5));
    return ndvi.rename("NDVI");
  },
  //MNDWI: (G - SWIR)/(G + SWIR)
  MNDWI: function (image) {
    var b3 = image.select("B3");
    var b6 = image.select("B6");
    var ndvi = b3.subtract(b6).divide(b3.add(b6));
    return ndvi.rename("MNDWI");
  },
  //NDVI: (B05 - B04)/(B05 + B04)
  NDVI: function (image) {
    var b5 = image.select("B5");
    var b4 = image.select("B4");
    var ndvi = b5.subtract(b4).divide(b5.add(b4));
    return ndvi.rename("NDVI");
  },
  //EVI: 2.5*(B05 - B04) / (B05 + 6*B04 - 7.5*B02 + 1)
  EVI: function (image) {
    var nir = image.select("B5").divide(10000);
    var red = image.select("B4").divide(10000);
    var blue = image.select("B2").divide(10000);
    var evi = nir
      .subtract(red)
      .multiply(2.5)
      .divide(nir.add(red.multiply(6)).subtract(blue.multiply(7.5)).add(1));
    return evi.rename("EVI");
  },
};
//点击“确定”按钮后调用的计算函数，用于计算选择的指标
function calcuate(roi, startDate, endDate, tag) {
  //影像集合
  var l8Col = pie.ImageCollection("LC08/01/T1");
  //通过日期过滤影像集合，并计算
  l8Col = l8Col
    .filterDate(startDate, endDate)
    .select(["B2", "B3", "B4", "B5", "B6", "BQA"])
    .filterBounds(roi)
    .map(function (image) {
      var qa = image.select("BQA");
      var cloudMask = qa.bitwiseAnd(1 << 4).eq(0);
      return image.updateMask(cloudMask);
    });
  var image = null;
  var vis = null;
  switch (tag) {
    case "LST":
      image = loadCol("USGS/MOD11A1/006", date[0], date[1], "LST_Day_1km", roi)
        .multiply(0.02)
        .subtract(273.15);
      vis = setVis(0, 40);
      addLegend("地表温度(°C)", [10, 20, 30, 40]);
      break;
    case "NDVI":
      image = l8Col.map(landsat8.NDVI).mean().clip(roi);
      vis = setVis(-0.2, 0.8);
      addLegend("NDVI Value", ["0", "0.6"]);
      break;
    case "NDWI":
      image = l8Col.map(landsat8.NDWI).mean().clip(roi);
      vis = setVis(-1, 0.3);
      addLegend("NDWI Value", ["-0.8", "0.1"]);
      break;
    case "MNDWI":
      image = l8Col.map(landsat8.MNDWI).mean().clip(roi);
      vis = setVis(-1, 0.3);
      addLegend("MNDWI Value", ["-0.8", "0.1"]);
      break;
    case "EVI":
      image = l8Col.map(landsat8.EVI).mean().clip(roi);
      vis = setVis(-0.2, 0.8);
      addLegend("EVI Value", ["0", "0.6"]);
      break;
    case "TVDI": //调用TVDI数据产品
      image = loadCol("BNU/GLOBAL_1KM_TVDI", date[0], date[1], "B1", roi);
      image = image.divide(10000);
      vis = setVis(0, 1);
      addLegend("TVDI Value(0~1)", ["0.25", "0.75"]);
      break;
    case "火点": //调用MODIS数据产品
      image = loadCol("USGS/MOD14A2/006", date[0], date[1], "FireMask", roi);
      vis = setVis(3, 8);
      addLegend("置信等级", ["<3", 4, 5, 6, 7, 8]);
      break;
  }
  if (mapID !== null) {
    Map.removeLayer(mapID); //如果有图层ID则将其移除，保证只有1个图层显示
  }
  mapID = Map.addLayer(image, vis, tag);
  currentImg = image;
}
//添加图例样式的函数，作用在于计算的项目发生改变时动态调整图例,参数：1）titile:string;2）labels:object[]
function addLegend(title, labels) {
  var data = {
    title: title,
    colors: [
      "#217303",
      "#268303",
      "#2a9203",
      "#2fa203",
      "#33b203",
      "#37c203",
      "#3bd203",
      "#40e203",
      "#44f203",
      "#4bfc09",
      "#56fd18",
      "#6dfe37",
      "#79fe47",
      "#8cff05",
      "#98ff04",
      "#a5fe04",
      "#b1fe03",
      "#befe02",
      "#cbfe02",
      "#d7fd02",
      "#e3fc02",
      "#effb02",
      "#faf802",
      "#f9eb02",
      "#f7dd03",
      "#f6cf03",
      "#f5c203",
      "#f4b503",
      "#f3a803",
      "#f29b04",
      "#f18e04",
      "#f08104",
      "#ef7404",
      "#ee6804",
      "#ed5b05",
      "#ec4f05",
      "#eb4305",
      "#e93705",
      "#e82b05",
      "#e72006",
      "#e61406",
      "#e50906",
    ],
    labels: labels,
    step: 30,
  };
  var style = {
    right: "150px",
    bottom: "10px",
    height: "70px",
    width: "350px",
  };
  if (maplegend !== null) {
    Map.removeUI(maplegend); //如果存在图例则将其移除，保证只有一个图例
  }
  maplegend = ui.Legend(data, style);
  Map.addUI(maplegend);
}
//导出当前图层所对应的影像
function exportCurrentMap(img, description, roi, scale) {
  if (currentImg !== null && animationlayerID.length == 0) {
    Export.image({
      image: img,
      description: description,
      region: roi,
      scale: scale,
    });
    print("导出成功！");
  } else {
    print("当前图层为空或图层不唯一！");
  }
}
//根据年份计算每个月的TVDI,并显示折线图。TVDI值越大，土壤湿度越低，反之土壤湿度越高
function calculateTVDI(start, end) {
  var img = pie
    .ImageCollection("BNU/GLOBAL_1KM_TVDI")
    .filterDate(start, end)
    .select("B1")
    .filterBounds(roi)
    .mean()
    .clip(roi)
    .divide(10000);
  return img;
}
function showTVDI(year) {
  var month = [
    "-01",
    "-02",
    "-03",
    "-04",
    "-05",
    "-06",
    "-07",
    "-08",
    "-09",
    "-10",
    "-11",
    "-12",
  ];
  var day = [
    "-31",
    "-28",
    "-31",
    "-30",
    "-31",
    "-30",
    "-31",
    "-31",
    "-30",
    "-31",
    "-30",
    "-31",
  ];
  var data = [];
  for (var i = 0; i < 12; i++) {
    var t1 = calculateTVDI(year + month[i] + "-01", year + month[i] + day[i]);
    var t2 = t1.reduceRegion(pie.Reducer.mean(), roi, 1000);
    data.push(t2);
  }
  var line_a = {
    title: year + "年TVDI变化",
    legend: ["TVDI"],
    xAxisName: "月份",
    yAxisName: "TVDI值",
    chartType: "line",
    yMin: 0,
    yMax: 1,
    smooth: true,
  };
  // 显示折线图
  var mark = [
    "01",
    "02",
    "03",
    "04",
    "05",
    "06",
    "07",
    "08",
    "09",
    "10",
    "11",
    "12",
  ];
  ChartImage(data, mark, line_a);
}
//显示某年动态图的函数
function showAnimation(year) {
  var month = [
    "-01",
    "-02",
    "-03",
    "-04",
    "-05",
    "-06",
    "-07",
    "-08",
    "-09",
    "-10",
    "-11",
    "-12",
  ];
  var day = [
    "-31",
    "-28",
    "-31",
    "-30",
    "-31",
    "-30",
    "-31",
    "-31",
    "-30",
    "-31",
    "-30",
    "-31",
  ];
  var data = [];
  if (mapID !== null) {
    Map.removeLayer(mapID);
  }
  if (animationlayerID.length > 0) {
    for (var i = 0; i < animationlayerID.length; i++) {
      Map.removeLayer(animationlayerID[i]);
    }
    animationlayerID = [];
  }
  switch (selectTag) {
    case "TVDI":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = calculateTVDI(start, end);
        var map = Map.addLayer(
          img,
          setVis(0, 1),
          year + month[i] + "TVDI",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "TVDI");
      }
      addLegend("TVDI Value(0~1)", ["0.25", "0.75"]);
      break;
    case "LST":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = loadCol("USGS/MOD11A1/006", start, end, "LST_Day_1km", roi)
          .multiply(0.02)
          .subtract(273.15);
        var map = Map.addLayer(
          img,
          setVis(0, 40),
          year + month[i] + "LST",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "LST");
      }
      addLegend("地表温度(°C)", [10, 20, 30, 40]);
      break;
    case "火点":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = loadCol("USGS/MOD14A2/006", start, end, "FireMask", roi);
        var map = Map.addLayer(
          img,
          setVis(3, 8),
          year + month[i] + "火点",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "火点");
      }
      addLegend("置信等级", ["<3", 4, 5, 6, 7, 8]);
      break;
    case "NDVI":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = l8Col_load(start, end).map(landsat8.NDVI).mean().clip(roi);
        var map = Map.addLayer(
          img,
          setVis(-0.2, 0.8),
          year + month[i] + "NDVI",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "NDVI");
      }
      addLegend("NDVI Value", ["0", "0.6"]);
      break;
    case "NDWI":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = l8Col_load(start, end).map(landsat8.NDWI).mean().clip(roi);
        var map = Map.addLayer(
          img,
          setVis(-1, 0.3),
          year + month[i] + "NDWI",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "NDWI");
      }
      addLegend("NDWI Value", ["-0.8", "0.1"]);
      break;
    case "MNDWI":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = l8Col_load(start, end).map(landsat8.MNDWI).mean().clip(roi);
        var map = Map.addLayer(
          img,
          setVis(-1, 0.3),
          year + month[i] + "MNDWI",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "MNDWI");
      }
      addLegend("MNDWI Value", ["-0.8", "0.1"]);
      break;
    case "EVI":
      for (var i = 0; i < 12; i++) {
        var img = null;
        var start = year + month[i] + "-01";
        var end = year + month[i] + day[i];
        img = l8Col_load(start, end).map(landsat8.EVI).mean().clip(roi);
        var map = Map.addLayer(
          img,
          setVis(-0.2, 0.8),
          year + month[i] + "EVI",
          false
        );
        animationlayerID.push(map);
        data.push(year + month[i] + "EVI");
      }
      addLegend("EVI Value", ["0", "0.6"]);
      break;
  }
  Map.playLayersAnimation(data, 1, -1); //动图间隔时间1秒，无限次循环。
}
Map.centerObject(roi, 5); //将地图中心转到研究范围
/* -------------------------以下代码是控件的布局以及事件的绑定等参数设置----------------------------- */
function funDateSelect(value) {
  date[0] = value[0];
  date[1] = value[1];
}
var dateSelect = ui.DateSelect({
  type: "daterange",
  placeholder: "请输入数值",
  value: ["2018-03-20", "2018-04-20"],
  onChange: funDateSelect,
  disabled: false,
});
function changeSelect(value) {
  selectTag = value;
}
var select1 = ui.Select({
  items: ["LST", "TVDI", "火点", "NDVI", "NDWI", "MNDWI", "EVI"],
  placeholder: "请选择",
  value: selectTag,
  multiple: false,
  onChange: changeSelect,
});
var selectIndex = ui.Label("选择项目：");
var selectPanel = ui.Panel({
  widgets: [selectIndex, select1],
  layout: ui.Layout.flow("horizontal"),
});
function inputArea(value) {
  areaCode = value;
  roi = getROI(areaCode);
}
var textBox3 = ui.TextBox({
  placeholder: "请输入行政区划编码",
  value: areaCode,
  onChange: inputArea,
  disabled: false,
});
var textboxName3 = ui.Label("更改行政区划(省级)：");
var txtPanel1 = ui.Panel({
  widgets: [textboxName3, textBox3],
  layout: ui.Layout.flow("horizontal"),
});
var selecDateLabel = ui.Label("选择日期范围：");
var txtPanel2 = ui.Panel({
  widgets: [selecDateLabel, dateSelect],
  layout: ui.Layout.flow("horizontal"),
});
//点击“确定”按钮调用的函数
function click_BtnOK() {
  print("当前计算项目：", selectTag + "," + date[0] + "~" + date[1]);
  //调用计算函数计算选择的指标添加到地图
  calcuate(roi, date[0], date[1], selectTag);
  if (animationlayerID.length > 0) {
    for (var i = 0; i < animationlayerID.length; i++) {
      Map.removeLayer(animationlayerID[i]);
    }
    animationlayerID = [];
  }
}
var btnOK = ui.Button({
  label: "确定",
  type: "success",
  onClick: click_BtnOK,
  style: { left: "50px" },
});
function click_btnExport() {
  exportCurrentMap(
    currentImg,
    date[0] + "-" + date[1] + selectTag,
    roi,
    exportScale
  );
}
var btnExport = ui.Button({
  label: "导出当前图层",
  type: "success",
  onClick: click_btnExport,
  style: { left: "50px" },
});
function changeScale(value) {
  exportScale = value;
}
var select2 = ui.Select({
  items: [30, 50, 100, 200, 500, 1000, 2000],
  placeholder: "请选择",
  value: exportScale,
  multiple: false,
  onChange: changeScale,
});
var selectPanel2 = ui.Panel({
  widgets: [ui.Label("选择导出分辨率（米）："), select2],
  layout: ui.Layout.flow("horizontal"),
});
function click_btnMonthly() {
  showAnimation(sec_year);
}
var btnMonthly = ui.Button({
  label: "显示当前指标每月动态图",
  type: "success",
  onClick: click_btnMonthly,
  style: { left: "10px" },
});
function click_showBtn() {
  //画出选择的年份TVDI变化图
  showTVDI(sec_year);
}
var btnShow = ui.Button({
  label: "显示TVDI变化折线图",
  type: "success",
  onClick: click_showBtn,
  style: { left: "10px" },
});
var btnPanel1 = ui.Panel({
  widgets: [btnOK, btnExport],
  layout: ui.Layout.flow("horizontal"),
});
function inputYear(value) {
  sec_year = value;
}
var txtBoxyear = ui.TextBox({
  placeholder: "请输入年份",
  value: sec_year,
  onChange: inputYear,
  disabled: false,
});
var labelyear = ui.Label("输入年份：");
var txtPanel3 = ui.Panel({
  widgets: [labelyear, txtBoxyear],
  layout: ui.Layout.flow("horizontal"),
});
var btnPanel2 = ui.Panel({
  widgets: [btnShow, btnMonthly],
  layout: ui.Layout.flow("horizontal"),
});
var panel = ui.Panel({
  widgets: [
    ui.Label("凉山彝族自治州火灾异常监测", { "font-size": "18px" }),
    ui.Label(
      "默认区域为凉山彝族自治州，若想更换区域请输入行政区代码(省级),若输入0则为默认区域",
      { "font-size": "18px" }
    ),
    selectPanel,
    txtPanel1,
    txtPanel2,
    btnPanel1,
    selectPanel2,
    txtPanel3,
    btnPanel2,
  ],
  style: {
    width: "400px",
    height: "500px",
    backgroundColor: "#fff",
  },
});
ui.root.add(panel);
/* 以上是网页上的整体框架布局*/

结果：

PIE-Engine APP:凉山州火灾高发地异常度分析系统

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