发布Google earth engine APP |基于光能利用率模型（CASA）和多源遥感数据模拟全球NPP

2021-06-04

5322

原创

### 数据预览
[![](http://www.seibert.cn/static/static/images/uploadimages/1_1593164588690.jpg)](http://www.seibert.cn/static/static/images/uploadimages/1_1593164588690.jpg)

### 操作视频
点击链接，观看视频https://www.seibert.cn/CASANPP.mp4

### 源码分享
    /**
     * Actual NPP is calculated using CASA model and multi-source remote sensing data
     *
     * 
     * 
     * @source
     * https://www.seibert.cn/
     * 
     * @Author Saibo Li, IGSNRR, CAS
     * 
     */ 
    
    /**
     ************
     *Parameters*
     ************
     */
     
    // Some pre-set locations of interest that will be loaded into a map.
    var locationDict = {
      'The default location': {lon: 115.65371234628795, lat: 34.42567414613981, zoom: 6}
    };
    // From "Show bounds" function
    var outline = null
    var boundLayer = null
    //  From "Calcute NPP" function
    var NPPMap = null
    // From "Show NPP" function
    var minMaxValue = null
    var CASANPPVisPar = null
    // From "Show NPP thumbnail" function
    var NPPVisParam= {
          min: 0, 
          max: 200,
          palette: 'FFFFFF, CE7E45, DF923D, F1B555, FCD163, 99B718, 74A901, 66A000, 529400,' +
            '3E8601, 207401, 056201, 004C00, 023B01, 012E01, 011D01, 011301'
        }
    // From "Creat polygon" function
    var polygons=""
    //  From "DIY time" function
    var date = "";
    
    
    /**
     *********
     *Service*
     *********
     */
    
    /**
     * Draw
     */
    function drawROI() {
      // Add an empty layer to hold the drawn points.
      mapPanel.drawingTools().addLayer([]);
      // Set the geometry type to be polygon.
      mapPanel.drawingTools().setShape('polygon');
      // Enter drawing mode.
      mapPanel.drawingTools().draw();
    }
    
    /**
     * Clear
     */
    function clearROI() {
      mapPanel.remove(boundLayer);
      polygons = null;
      mapPanel.drawingTools().clear();
    }
    
    /**
     * Creat polygon
     * This function gets called when the geometry layer changes.
     * Use debounce to call the function at most every 100 milliseconds.
     */
      
    var getNewROI = ui.util.debounce(function() {
      // Creat polygon
      polygons = mapPanel.drawingTools().layers().get(0).toGeometry();
      mapPanel.drawingTools().layers().get(0).setShown(false);
      showBounds(polygons)
      print("You have identified your research area")
    }, 100);
    
    /**
     * Show bounds
     * @param  {ee.Geometry}  [bound as layer]
     */
    function showBounds(region) {
      outline = ee.Image()
                      .toByte()
                      .paint({
                        featureCollection:region,
                        color:0,
                        width:1.5
                      });
      // boundLayer can be cleared, if you click "Clear ROI" button 
      boundLayer = mapPanel.addLayer(outline, {palette: "1b3eff"}, "bounds");
    }
    
    /**
     * Calcute NPP
     */
    function calcuteNPP() {
      var casaNPP = require('users/seibertli602/units:js/casaNPPAPP.js');
      NPPMap = casaNPP.NPP(polygons,date);
      if(NPPMap){
          print("The data has been processed. You can click the 'show' button to display the results")
      }
    }
    
    /**
     * Show NPP
     */
    function showNPP() {
      // // Set minMaxValue to show NPPMap
      // var casaNPP = require('users/seibertli602/units:js/casaNPPAPP.js');
      // minMaxValue = casaNPP.showNPP(NPPMap,polygons);
      
      // Add NPP layer
      CASANPPVisPar={min:0,max:200,palette: 'FFFFFF, CE7E45, DF923D, F1B555, FCD163, 99B718, 74A901, 66A000, 529400,3E8601, 207401, 056201, 004C00, 023B01, 012E01, 011D01, 011301'}
      mapPanel.addLayer(NPPMap.reproject('EPSG:4326', null, 5000),CASANPPVisPar,"CASANpp")
      // Add legend
      var legend  = require('users/seibertli602/units:js/legend.js');
      var legendFVC  = legend.grad_legend(CASANPPVisPar, date+'NPP gc/y', false); 
      legend.add_lgds([legendFVC],mapPanel,'bottom-right');
      // Set ui.Map parameters
      mapPanel.centerObject(polygons, 8);
      mapPanel.style().set('cursor', 'crosshair');
      print("Show layer would be slow")
      print("If the map is loaded successfully,")
      print("you can click on the map to inspect the layers")
    }
    
    /**
     * Show NPP thumbnail
     */
    function showNPPThumbnail() {
      var VisParam = CASANPPVisPar || NPPVisParam
      var thumbnail = ui.Thumbnail({
        image: NPPMap.visualize(VisParam),
        params: {
          dimensions: "1024x1024",  //Thumbnail size
          region: polygons.toGeoJSON(), //Geoinfo
          format: "png"  //Format
        },
        style: {height: "300px", width: "300px"},
      });
      print(thumbnail);
    }
    
    /**
     * Export NPP image
     */
    function exportNPP() {
       Export.image.toDrive({
            image: NPPMap,
            description: date+'NPP',
            folder: "NPP", 
            fileNamePrefix: date+'NPP',
            crs: "EPSG:4326",
            region: polygons,
            scale: 1000,
            maxPixels: 1e13
        });
    }
    
    
    /**
     *********
     ***GUI***
     *********
     */
    
    // Now let's do some overall layout.
    // Create a map panel.
    var mapPanel = ui.Map();
    
    // Take all tools off the map except the zoom and mapTypeControl tools.
    mapPanel.setControlVisibility(
        {all: false, zoomControl: true, mapTypeControl: true,layerList:true});
    
    // Center the map
    var defaultLocation = locationDict['The default location'];
    mapPanel.setCenter(
        defaultLocation.lon, defaultLocation.lat, defaultLocation.zoom);
    
    // Don't make imports that correspond to the drawn points.
    mapPanel.drawingTools().setLinked(false);    
    // Limit the draw modes to polygons.
    mapPanel.drawingTools().setDrawModes(['polygon']);
    mapPanel.setOptions("SATELLITE");
    // Add these to the interface.
    ui.root.widgets().reset([mapPanel]);
    ui.root.setLayout(ui.Panel.Layout.flow('horizontal'));
    
    /*
     * Additional component configuration
     */
    
    // Add a title and some explanatory text to a side panel.
    var header = ui.Label('Global NPP', {fontSize: '36px', color: 'Black',stretch: 'horizontal',textAlign:'center',margin:'8px 8px 0px 8px'});
    var text = ui.Label(
        'Actual NPP is calculated using CASA model and multi-source remote sensing data.',
        {fontSize: '15px',margin:'0px 8px 8px 8px',textAlign:'left'});
    var dataText = ui.Label('Dataset Availability:2000 - true',{fontSize: '15px',margin:'0px 8px 8px 8px',textAlign:'left'})
    var toolPanel = ui.Panel([header, text, dataText], 'flow', {width: '400px'});
    ui.root.add(toolPanel);
    
    // Create a hyperlink to an external reference.
    var link = ui.Label(
        'Seibert website (绠€鐮�) by Saibo Li', {fontSize: '14px',fontWeight: 'bold',height:'16px'},
        'https://www.seibert.cn/');
    var linkPanel = ui.Panel(
        [ui.Label('For more information:', {fontWeight: 'bold',fontSize: '14px',height:'16px'}), link],ui.Panel.Layout.flow('horizontal'),{});
    toolPanel.add(linkPanel);
    
    // DIY roi
    var roiLabel = ui.Label("(1) Click 'Draw ROI' button, then use the mouse to draw your research area");
    var roiBtn = ui.Button({
        label: "Draw ROI",
        onClick: drawROI
      });
    var clearROIBtn = ui.Button({
        label: "Clear ROI",
        onClick: clearROI
      });
    toolPanel.add(ui.Panel([roiLabel,ui.Panel([roiBtn,clearROIBtn],ui.Panel.Layout.flow('horizontal'),{})],'flow',{border:"1px solid black",margin:"2px",textAlign:'left'}));
    
    // DIY time
    var startLabel = ui.Label("(2) Enter the time in the input box below (time: yyyy)");
    var startTextbox = ui.Textbox({
      placeholder: "e.g. 2015",
      value: date,
      onChange: function(value) {
        print("Time: " + value);
        date = value;
      }
    });
    toolPanel.add(ui.Panel([startLabel,startTextbox],'flow',{border:"1px solid black",margin:"2px",textAlign:'left'}));
    
    // Run
    var runBtn = ui.Button({
        label: "Run",
        onClick: calcuteNPP
      });
      
    // Show
    var showBtn = ui.Button({
        label: "Show layer",
        onClick: showNPP
      });
    
    
    // Show Thumbnail
    var showThumbnailBtn = ui.Button({
        label: "Show thumbnail",
        onClick: showNPPThumbnail
      });
      
    // Export
    var exportBtn = ui.Button({
        label: "Export NPP",
        onClick: exportNPP
      });
    toolPanel.add(ui.Panel([runBtn,showBtn,showThumbnailBtn,exportBtn],ui.Panel.Layout.flow('horizontal'),{}))
    
    // Set the callback function on changes of the geometry layer.
    mapPanel.drawingTools().onEdit(getNewROI);
    mapPanel.drawingTools().onDraw(getNewROI);
    mapPanel.drawingTools().onErase(getNewROI);