create_strata_using_LUT.txt

/**
 * 
 * Create stratification for multiple years using a lookup table
 * 
 * Author: Paulo Arevalo (parevalo@bu.edu)
 * 
 * Please cite as:
 * Arévalo, P., Bullock, E.L., Woodcock, C.E., Olofsson, P., 2020. 
 * A Suite of Tools for Continuous Land Change Monitoring in Google Earth Engine. 
 * Front. Clim. 2. https://doi.org/10.3389/fclim.2020.576740
 * 
*/

var visLabels = {
  fontWeight: 'bold', 
  fontSize: '14px', 
  padding: '4px 4px 4px 4px', 
  border: '1px solid black',
  color: 'white',
  backgroundColor: 'black',
  textAlign: 'left',
  stretch: 'horizontal'
  }

var boldLabels = {
  fontWeight: 'bold', 
  textAlign: 'center',
  stretch: 'horizontal'
  }

var horizontalStyle = {stretch: 'horizontal', width: '100%'}

// Set interface and initialize app
var app = {}

function lutRowMaker(label){
  return ui.Panel([
    // ui.Label({value: label, style:{width: '12%', stretch:'vertical'}}),
    ui.Textbox({style: {stretch: 'horizontal'}}),
    ui.Textbox({style: {stretch: 'horizontal'}}),
    ui.Textbox({style: {stretch: 'horizontal'}})
  ], 
  ui.Panel.Layout.Flow('horizontal'),
  horizontalStyle)
}

function addRowCallback(label){
  app.main.LUT.add(lutRowMaker())
}



function applyLUT(){
  
  // Need to be re-set every time, otherwise list will accumulate if
  // create strata is clicked twice and that will result in classification
  // that does not show the actual reclass values
  var fromValues = []
  var toValues = []
  var reclassValues = []
  
  app.main.LUT.widgets().map(function(x){
    var fromValue =  parseInt(x.widgets().get(0).getValue())
    var toValue =  parseInt(x.widgets().get(1).getValue())
    var reclassValue =  parseInt(x.widgets().get(2).getValue())
    fromValues.push(fromValue)
    toValues.push(toValue)
    reclassValues.push(reclassValue)
  })
  
  
  // print(fromValues)
  // print(toValues)
  // print(reclassValues)
  
  // Get years from and to
  var yearsFrom = app.main.yearsFrom.widgets().get(1).getValue().split(',')
      .map(function(x){return x.trim()})
  var yearsTo = app.main.yearsTo.widgets().get(1).getValue().split(',')
      .map(function(x){return x.trim()})
  
  // print(yearsFrom)
  // print(yearsTo)
  
  //Get fill value
  var fillValue = parseInt(app.main.fillValue.widgets().get(1).getValue())
  
  // Map over periods and create stratification
  var periodStrata =  ee.Image.cat(yearsFrom.map(function(y, i){
    var time1 = LAYERS.landCoverMaps.select('.*' + y + '.*') 
    var time2 = LAYERS.landCoverMaps.select('.*' + yearsTo[i] + '.*')
     
    var test = time1.eq(ee.Image(fromValues)).and(time2.eq(ee.Image(toValues)))
      .multiply(reclassValues)
      .reduce(ee.Reducer.sum())
      
    var final = test.where(test.eq(0), fillValue)
    return final.rename('Strata_' + y + '-' + yearsTo[i])
      
  }))
  
  print("Strata bands created: ", periodStrata)
  app.main.mapPanel.centerObject(LAYERS.landCoverMaps)
  app.main.mapPanel.addLayer(periodStrata.select(0).randomVisualizer(), {}, "First strata")
  
  print(ui.Chart.image.histogram({
    image: periodStrata.select(0), 
    region:LAYERS.landCoverMaps.geometry(), 
    scale:30, 
    maxPixels:1e13
    
  }))
  
  Export.image.toAsset({
    description: "Export_to_asset",
    image: periodStrata,
    scale: 30,
    maxPixels:1e13,
    region: LAYERS.landCoverMaps.geometry(),
    pyramidingPolicy: {'.default': 'mode'}
    
  })
  
  Export.image.toDrive({
    description: "Export_to_drive",
    image: periodStrata.toDouble(),
    scale: 30,
    maxPixels:1e13,
    region: LAYERS.landCoverMaps.geometry(),
  })
  
  // var time1 = image.select('LC_2010-07-01') 
  // var time2 = image.select('LC_2015-07-01')
  
  // var test = time1.eq(ee.Image(fromValues)).and(time2.eq(ee.Image(toValues)))
  //     .multiply(reclassValues)
  //     .reduce(ee.Reducer.sum())
      
  // var final = test.where(test.eq(0), fillValue)
  
  // app.main.mapPanel.addLayer(time1.randomVisualizer())
  // app.main.mapPanel.addLayer(time2.randomVisualizer())
  // app.main.mapPanel.addLayer(final.randomVisualizer())
  
}

var LAYERS = {}

var initApp = function(){
  ui.root.clear()
  
  app.main = []
  app.main.mainPanel = ui.Panel()
  app.main.mapPanel = ui.Map({
    // onClick: mapCallback,
    style: {
      // height: '80%',
      cursor: 'crosshair'
    }
  })
  
  app.main.inputMaps = ui.Panel([
    ui.Label({value: 'Image path', style:{width: '12%', stretch:'vertical'}}),
    ui.Textbox({
      // value: 'projects/GLANCE/RESULTS/CLASSIFICATION/VERSION_1/NA/V1-2/LCMAPSFixedSynt_256',
      placeholder: 'projects/GLANCE/RESULTS/CLASSIFICATION/VERSION_1/NA/V1-2/LCMAPSFixedSynt_256',
      style: {stretch: 'horizontal'}
    })
  ], 
  ui.Panel.Layout.Flow('horizontal'),
  horizontalStyle)
  
  app.main.fillValue = ui.Panel([
    ui.Label({value: 'Fill value', style:{width: '12%', stretch:'vertical'}}),
    ui.Textbox({style: {stretch: 'horizontal'}})
  ], 
  ui.Panel.Layout.Flow('horizontal'),
  horizontalStyle)
  
  app.main.yearsFrom = ui.Panel([
    ui.Label({value: 'Years from', style:{width: '12%', stretch:'vertical'}}),
    ui.Textbox({
      placeholder: '2001, 2002, 2003',
      value: '2001, 2002, 2003',
      style: {stretch: 'horizontal'}})
  ], 
  ui.Panel.Layout.Flow('horizontal'),
  horizontalStyle)
  
  app.main.yearsTo = ui.Panel([
    ui.Label({value: 'Years to', style:{width: '12%', stretch:'vertical'}}),
    ui.Textbox({
      placeholder: '2002, 2003, 2004',
      value: '2002, 2003, 2004', 
      style: {stretch: 'horizontal'}})
  ], 
  ui.Panel.Layout.Flow('horizontal'),
  horizontalStyle)
  
  app.main.LUTHeaders = ui.Panel([
    ui.Label({value: 'Class from', style: boldLabels}),
    ui.Label({value: 'Class to', style: boldLabels}),
    ui.Label({value: 'New value', style: boldLabels})
  ], 
  ui.Panel.Layout.Flow('horizontal'),
  horizontalStyle)
  
  app.main.addRow = ui.Button({
    label: 'Add row', 
    onClick: addRowCallback,
    style:{stretch: 'horizontal'}
  })
  
  app.main.loadMaps = ui.Button({
    label: 'Load maps', 
    onClick: function(x){
      LAYERS.landCoverMaps = ee.Image(app.main.inputMaps.widgets().get(1).getValue())
      print("Available bands are: ", LAYERS.landCoverMaps.bandNames())
    },
    style:{stretch: 'horizontal'}
  })

  app.main.retrieveLUT = ui.Button({
    label: 'Create strata', 
    onClick: applyLUT,
    style:{stretch: 'horizontal'}
  })
  
  app.main.LUT = ui.Panel({
    widgets: []
  })
  
  app.main.LUTPanel = ui.Panel({
    style: {width: '30%'},
    widgets: [ui.Label('Load land cover image', visLabels), 
    app.main.inputMaps, app.main.loadMaps, 
    ui.Label('Set LUT to create map stratification ', visLabels),
    app.main.yearsFrom, app.main.yearsTo, app.main.fillValue, 
    app.main.addRow, app.main.LUTHeaders, app.main.LUT, app.main.retrieveLUT]
  })
  
  
  var fullUI = ui.SplitPanel(app.main.mapPanel, app.main.LUTPanel, 'horizontal')
  ui.root.add(fullUI)
                        
}

initApp()




// var time1 = image.select('LC_2010-07-01') 
// var time2 = image.select('LC_2015-07-01') 

// Map.addLayer(time1.randomVisualizer(), {}, "time1")
// Map.addLayer(time2.randomVisualizer(), {}, "time2")

// var from = [1,2,3,4,5,6,7,5,5,6,5]
// var to = [1,2,3,4,5,6,7,7,6,7,3]
// var newValue = [1,2,3,4,5,6,7,8, 9, 10, 11]
// var fillValue = 12

// var newValueImg = ee.Image(newValue)
// print(newValueImg)

// //
// var test = time1.eq(ee.Image(from)).and(time2.eq(ee.Image(to))).multiply(newValue)
//     .reduce(ee.Reducer.sum())
    
// var final = test.where(test.eq(0), fillValue)

    
// Map.addLayer(test.randomVisualizer(), {}, "test")
// Map.addLayer(final.randomVisualizer(), {}, "final")


// var horizontalStyle = {stretch: 'horizontal', width: '100%'}

// function lutRowMaker(label){
//   return ui.Panel([
//     ui.Label({value: label, style:{width: '12%', stretch:'vertical'}}),
//     ui.Textbox({style: {stretch: 'horizontal'}}),
//     ui.Textbox({style: {stretch: 'horizontal'}}),
//     ui.Textbox({style: {stretch: 'horizontal'}})
//   ], 
//   ui.Panel.Layout.Flow('horizontal'),
//   horizontalStyle)
// }

// print(lutRowMaker('C1'))

// var addRow = ui.Button({label: 'Add row', onClick:function(x){print(lutRowMaker('C1'))}})
// Map.add(addRow)