Open Google Earth Engine（OEEL）——oeel.plotly.plot绘制MODIS影像中土地分类的变化情况

oeel.Element.addTimeProperties(sinceEpoch, timeVariable, timeZone, image, feature, collection)

oeel.plotly.plot()

var geometry = /* color: #d63000 */ee.Geometry.Polygon(
        [[[-60.270601562500005, -1.4604924790211367],
          [-60.270601562500005, -9.264255286247176],
          [-50.338960937500005, -9.264255286247176],
          [-50.338960937500005, -1.4604924790211367]]], null, false);
Map.setOptions('SATELLITE')
var oeel=require('users/OEEL/lib:loadAll')
var color= ['000000',
  '05450a', '086a10', '54a708', '78d203', '009900', 'c6b044', 'dcd159',
  'dade48', 'fbff13', 'b6ff05', '27ff87', 'c24f44', 'a5a5a5', 'ff6d4c',
  '69fff8', 'f9ffa4', '1c0dff'
];
var igbpLandCover = ee.ImageCollection('MODIS/006/MCD12Q1').select("LC_Type1").map(oeel.Element.addTimeProperties());
var igbpLandCoverVis = {
  min: 0.0,
  max: 17.0,
  palette:color,
};
  
  
function getPlot(igbpLandCover,step, geometry){
  igbpLandCover=ee.ImageCollection(igbpLandCover).filter(ee.Filter.inList("oeel:start_year", ee.List.sequence(2000,2021,step)));
  
  var size=igbpLandCover.size();
  var scale=500;
  
  var NoC=17;
  
  var reducer=ee.Reducer.fixed2DHistogram({
    xMin:1,
    xMax:NoC+1,
    xSteps:NoC,
    yMin:1,
    yMax:NoC+1,
    ySteps:NoC,
  });
  
  function hist2DtoList(data,index,numberClass){
    return ee.Array.cat([
      ee.Array(data.get('histogram')),
      ee.Array(data.get('xBuckets')).add(index.multiply(numberClass)).reshape([1,-1]).repeat(0,ee.Array(data.get('yBuckets')).toList().size()),
      ee.Array(data.get('yBuckets')).add(index.add(1).multiply(numberClass)).repeat(1,ee.Array(data.get('xBuckets')).toList().size()),
      ],
      2).reshape([-1,3]);
  }
  
  
  var data=ee.List.sequence(0,size.subtract(2),1).map(function(index){
    index=ee.Number(index);
    return hist2DtoList(ee.Dictionary(igbpLandCover.toBands().select([index,index.add(1)]).reduceRegion(reducer,geometry,scale)),
    index,NoC+1);
  });
  
  data=ee.Array.cat(data,0).transpose();
  
  data=ee.Array.cat([data,data.slice(0,0,1).sqrt()],0);
  data=data.toList();
  
  var colors=ee.List.repeat(color,size).flatten();
  var labels=ee.List.repeat(igbpLandCover.aggregate_array("oeel:start_year"),NoC+1).unzip().flatten();
  
  var col=igbpLandCover.toList(size);
  
  // genration of custom plot
  return {
    type: "sankey",
    orientation: "h",
    node: {
      pad: 10,
      thickness: 25,
      line: {
        color: "black",
        width: 0.1
      },
     label: labels,
     color: colors
        },
  
    link:ee.Dictionary.fromLists(["label","source", "target","value"], data)
  };
}
var plot=oeel.plotly.plot();
// add custom plot
plot.addCustom(getPlot(igbpLandCover,1,geometry))
plot.layout.autosize=true;
Map.centerObject(geometry, 6);
//empty layer, to be used in onclick
var sourceMap=Map.addLayer(ee.Image(), igbpLandCoverVis, 'IGBP Land Cover source');
var destMap=Map.addLayer(ee.Image(), igbpLandCoverVis, 'IGBP Land Cover dest');
var maskMap=Map.addLayer(ee.Image(), {opacity:0.8}, 'mask');
// on click on the plot
plot.on('click',function(event){
  var srcImage=igbpLandCover.filter(ee.Filter.eq('oeel:start_year',event.points[0].source.label)).first();
  var dstImage=igbpLandCover.filter(ee.Filter.eq('oeel:start_year',event.points[0].target.label)).first();
  var srcMak=srcImage.eq(color.indexOf(event.points[0].source.color));
  var destMak=dstImage.eq(color.indexOf(event.points[0].target.color));
  var mask=srcMak.and(destMak)
  sourceMap.setEeObject(srcImage.updateMask(srcMak))
  destMap.setEeObject(dstImage.updateMask(destMak))
  maskMap.setEeObject(ee.ImageCollection([ee.Image.constant(0).eq(0),mask.eq(0)]).select([0],['mask']).mosaic().selfMask().not())
})
ui.root.insert(0,plot.widget({stretch:'horizontal',margin:0}))
ui.root.setLayout(ui.Panel.Layout.flow('vertical'))
var step=1;
// add a slider 
Map.add(ui.Slider({
min:1,
max:5,
value:1,
step:1,
  onChange:function(val){
    step=val;
    plot.data=[getPlot(igbpLandCover,step,Map.drawingTools().toFeatureCollection('id').geometry(1000))];
    plot.update()
  },
  direction:'vertical',
  style:{position:'middle-right'},
}))
// get geoemtry change
Map.drawingTools().onEdit(ui.util.throttle(function(){
  plot.data=[getPlot(igbpLandCover,step,Map.drawingTools().toFeatureCollection('id').geometry(1000))];
  plot.update()
},1000))
// print all OEEL function used
print('list of functions used',oeel.refs());