Landsat 5 and 8 RGB time series explorer

landsat_5_8_rgb_time_series_explorer.js

/**
 * @license
 * Copyright 2021 Justin Braaten
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// #############################################################################
// ### IMPORT MODULES ###
// #############################################################################

// RGB time series charting module: https://github.com/jdbcode/ee-rgb-timeseries
var rgbTs = require(
  'users/jstnbraaten/modules:rgb-timeseries/rgb-timeseries.js'); 



// #############################################################################
// ### GET URL PARAMS ###
// #############################################################################

var initRun = 'false';
var runUrl = ui.url.get('run', initRun);
ui.url.set('run', runUrl);

var initLon = -121.68804;
var lonUrl = ui.url.get('lon', initLon);
ui.url.set('lon', lonUrl);

var initLat = 36.46517;
var latUrl = ui.url.get('lat', initLat);
ui.url.set('lat', latUrl);

var initIndex = 'NBR';
var indexUrl = ui.url.get('index', initIndex);
ui.url.set('index', indexUrl);

var initRgb = 'SWIR1/NIR/GREEN';
var rgbUrl = ui.url.get('rgb', initRgb);
ui.url.set('rgb', rgbUrl);

var initDuration = 12;
var durationUrl = ui.url.get('duration', initDuration);
ui.url.set('duration', durationUrl);

var initCloud = 30;
var cloudUrl = ui.url.get('cloud', initCloud);
ui.url.set('cloud', cloudUrl);


var initStart = '1984';
var startUrl = ui.url.get('start', initStart);
ui.url.set('start', startUrl);

var initEnd = new Date().getFullYear();
var endUrl = ui.url.get('end', initEnd);
ui.url.set('end', endUrl);



// #############################################################################
// ### DEFINE UI ELEMENTS ###
// #############################################################################

// Style.
var CONTROL_PANEL_WIDTH = '280px';
var CONTROL_PANEL_WIDTH_HIDE = '141px';
var textFont = {fontSize: '12px'};
var headerFont = {
  fontSize: '13px', fontWeight: 'bold', margin: '4px 8px 0px 8px'};
var sectionFont = {
  fontSize: '16px', color: '#808080', margin: '16px 8px 0px 8px'};
var infoFont = {fontSize: '11px', color: '#505050'};

// Control panel.
var controlPanel = ui.Panel({
  style: {position: 'top-left', width: CONTROL_PANEL_WIDTH_HIDE,
    maxHeight: '90%'
  }});

// Info panel.
var infoElements = ui.Panel(
  {style: {shown: false, margin: '0px -8px 0px -8px'}});

// Element panel.
var controlElements = ui.Panel(
  {style: {shown: false, margin: '0px -8px 0px -8px'}});

// Instruction panel.
var instr = ui.Label('Click on a location',
  {fontSize: '15px', color: '#303030', margin: '0px 0px 6px 0px'});

// Show/hide info panel button.
var infoButton = ui.Button(
  {label: 'About ❯', style: {margin: '0px 4px 0px 0px'}});

// Show/hide control panel button.
var controlButton = ui.Button(
  {label: 'Options ❯', style: {margin: '0px 0px 0px 0px'}});

// Info/control button panel.
var buttonPanel = ui.Panel(
  [infoButton, controlButton],
  ui.Panel.Layout.Flow('horizontal'),
  {stretch: 'horizontal', margin: '0px 0px 0px 0px'});

// Options label.
var optionsLabel = ui.Label('Options', sectionFont);
optionsLabel.style().set('margin', '16px 8px 2px 8px');

// Information label.
var infoLabel = ui.Label('About', sectionFont);

// Information text. 
var aboutLabel = ui.Label(
  'This app shows a time series chart for Landsat TM and OLI surface ' +
  'reflectance at a given location. Time series ' +
  'point colors are defined by RGB assignment to selected bands where ' +
  'intensity is based on the area-weighted mean pixel value within a 45 meter ' +
  'radius around the clicked point in the map.',
  infoFont);

var appCodeLink = ui.Label({
  value: 'App source code',
  style: {fontSize: '11px', color: '#505050', margin: '-4px 8px 0px 8px'}, 
  targetUrl: 'https://github.com/jdbcode/ee-rgb-timeseries/blob/main/eo-timeseries-explorer.js'
});

// Y-axis index selection.
var indexLabel = ui.Label('Y-axis index', headerFont);
var indexList = ['NBR', 'NDVI', 'Blue', 'Green', 'Red',
                 'NIR', 'SWIR1', 'SWIR2'];
var indexSelect = ui.Select(
  {items: indexList, value: ui.url.get('index'), style: {stretch: 'horizontal'}});
var indexPanel = ui.Panel(
  [indexLabel, indexSelect], null, {stretch: 'horizontal'});

// RGB bands selection.
var rgbLabel = ui.Label({value: 'RGB visualization', style: headerFont});
var rgbList = ['SWIR1/NIR/GREEN', 'RED/GREEN/BLUE', 'NIR/RED/GREEN',
               'NIR/SWIR1/RED'];
var rgbSelect = ui.Select({
  items: rgbList, placeholder: ui.url.get('rgb'),
  value: ui.url.get('rgb'), style: {stretch: 'horizontal'}
});
var rgbPanel = ui.Panel([rgbLabel, rgbSelect], null, {stretch: 'horizontal'});

// Duration.
var durationLabel = ui.Label(
  {value: 'Duration (months prior)', style: headerFont});
var durationSlider = ui.Slider({
  min: 1, max: 24 , value: parseInt(ui.url.get('duration')),
  step: 1, style: {stretch: 'horizontal'}
});
var durationPanel = ui.Panel(
  [durationLabel, durationSlider], null, {stretch: 'horizontal'});

// Start year
var startYearLabel = ui.Label(
  {value: 'Start year', style: headerFont});
var startYearTextbox = ui.Textbox({
  value: ui.url.get('start'), style: {stretch: 'horizontal'}
});
var startYearPanel = ui.Panel(
  [startYearLabel, startYearTextbox], null, {stretch: 'horizontal'});

// End year
var endYearLabel = ui.Label(
  {value: 'End year', style: headerFont});
var endYearTextbox = ui.Textbox({
  value: ui.url.get('end'), style: {stretch: 'horizontal'}
});
var endYearPanel = ui.Panel(
  [endYearLabel, endYearTextbox], null, {stretch: 'horizontal'});

// Cloud threshold.
var cloudLabel = ui.Label(
  {value: 'Cloud threshold % (exclude >)', style: headerFont});
var cloudSlider = ui.Slider({
  min: 0, max: 100 , value: parseInt(ui.url.get('cloud')),
  step: 1, style: {stretch: 'horizontal'}
});
var cloudPanel = ui.Panel(
  [cloudLabel, cloudSlider], null, {stretch: 'horizontal'});

// Panel to hold the chart.
var chartHeight = '325px';
var chartPanel = ui.Panel(
  {style: {Height: chartHeight, minHeight: chartHeight, maxHeight: chartHeight}});

// Map widget.
var map = ui.Map();

// Map/chart panel
var mapChartSplitPanel = ui.SplitPanel({
  firstPanel: map, //
  secondPanel: chartPanel,
  orientation: 'vertical',
  wipe: false,
});

// Submit changes button.
var submitButton = ui.Button({
  label: 'Submit changes',
  style: {stretch: 'horizontal', shown: false}
});



// #############################################################################
// ### DEFINE INITIALIZING CONSTANTS ###
// #############################################################################

// Set color of the circle to show on map and images where clicked
var AOI_COLOR = 'ffffff';  //'b300b3';

var COORDS = null;
var CLICKED = false;

// Set region reduction and chart params.
var OPTIONAL_PARAMS = {
  reducer: ee.Reducer.mean(),
  scale: 20,
  crs: 'EPSG:4326',
  chartParams: {
    pointSize: 11,
    legend: {position: 'none'},
    hAxis: {title: 'Date', titleTextStyle: {italic: false, bold: true}},
    vAxis: {
      title: indexSelect.getValue(),
      titleTextStyle: {italic: false, bold: true}
    },
    explorer: {axis: 'horizontal'}
  },
  chartStyle: {
    height: chartHeight,
    margin: '0px',
    padding: '0px'
  }
};

var sensorInfo = {
  'Landsat-8 SR': {
    scale: 30,
    aoiRadius: 45,
    index: {
      NBR: 'NBR',
      NDVI: 'NDVI',
      Blue: 'B2',
      Green: 'B3',
      Red: 'B4',
      NIR: 'B5',
      SWIR1: 'B6',
      SWIR2: 'B7'
    },
    rgb: {
      'SWIR1/NIR/GREEN': {
        bands: ['B6', 'B5', 'B3'],
        min: [100, 151 , 50],
        max: [4500, 4951, 2500],
        gamma: [1, 1, 1]
      },
      'RED/GREEN/BLUE': {
        bands: ['B4', 'B3', 'B2'],
        min: [0, 50, 50],
        max: [2500, 2500, 2500],
        gamma: [1.2, 1.2, 1.2]
      },
      'NIR/RED/GREEN': {
        bands: ['B5', 'B4', 'B3'],
        min: [151, 0, 50],
        max: [4951, 2500, 2500],
        gamma: [1, 1, 1]
      },
      'NIR/SWIR1/RED': {
        bands: ['B5', 'B6', 'B3'],
        min: [151, 100, 50],
        max: [4951, 4500, 2500],
        gamma: [1, 1, 1]
      }      
    }
  }
};



// #############################################################################
// ### DEFINE FUNCTIONS ###
// #############################################################################

/**
 * Selects and renames bands of interest for TM/ETM+.
 */
function renameEtm(img) {
  return img.select(
    ['B1', 'B2', 'B3', 'B4', 'B5', 'B7'],
    ['B2', 'B3', 'B4', 'B5', 'B6', 'B7']);
}

/**
 * Prepar OLI images.
 */
function prepOli(img) {
 return addDate(addBands(img));
}

/**
 * Prepares TM/ETM+ images.
 */
function prepTm(img) {
  return addDate(addBands(renameEtm(img)));
}

/**
 * Add NDVI and NBR bands.
 */
function addBands(img) {
  var nbr = img.normalizedDifference(['B5', 'B7']).rename(['NBR']);
  var ndvi = img.normalizedDifference(['B5', 'B4']).rename('NDVI');
  return img.addBands(ee.Image.cat(nbr, ndvi));
}

/**
 * Add date property.
 */
function addDate(img) {
  var date = img.date().format('YYYY-MM-dd');
  return img.set('date', date);
}

/**
 * Gathers all Landsat into a collection.
 */
function getLandsatCollection(aoi, startDate, endDate, cloudthresh) {
  var tmCol = ee.ImageCollection('LANDSAT/LT05/C01/T1_SR')
    .filterBounds(aoi)
    .filterDate(startDate, endDate)
    .filter(ee.Filter.lt('CLOUD_COVER', cloudthresh))
    .map(prepTm);
  
  var oliCol = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR')
    .filterBounds(aoi)
    .filterDate(startDate, endDate)
    .filter(ee.Filter.lt('CLOUD_COVER', cloudthresh))
    .map(prepOli);
  
  return tmCol.merge(oliCol);
}

/**
 * Generates chart and adds image cards to the image panel.
 */
function renderGraphics(coords) {
  var dataType = 'Landsat-8 SR';
  
  // Get the selected RGB combo vis params.
  var visParams = sensorInfo[dataType]['rgb'][rgbSelect.getValue()];
  
  // Get the clicked point and buffer it.
  var point = ee.Geometry.Point(coords);
  var aoiCircle = point.buffer(sensorInfo[dataType]['aoiRadius']);

  // Clear previous point from the Map.
  map.layers().forEach(function(el) {
    map.layers().remove(el);
  });

  // Add new point to the Map.
  map.addLayer(aoiCircle, {color: AOI_COLOR});
  map.centerObject(aoiCircle, 14);

  // Get collection options.
  var cloudThresh = cloudSlider.getValue();
  var startDate = ee.Date(startYearTextbox.getValue() + '-01-01');
  var endDate = ee.Date(endYearTextbox.getValue() + '-01-01').advance(1, 'year');

  // Build the collection.
  var col = getLandsatCollection(aoiCircle, startDate, endDate, cloudThresh).sort('system:time_start');
  print('len', col.size())

  OPTIONAL_PARAMS['chartParams']['vAxis']['title'] = indexSelect.getValue();
  OPTIONAL_PARAMS['scale'] = sensorInfo[dataType]['scale'];

  // Render the time series chart.
  rgbTs.rgbTimeSeriesChart(col, aoiCircle,
    sensorInfo[dataType]['index'][indexSelect.getValue()],
    sensorInfo[dataType]['rgb'][rgbSelect.getValue()],
    chartPanel, OPTIONAL_PARAMS);
}

/**
 * Handles map clicks.
 */
function handleMapClick(coords) {
  CLICKED = true;
  COORDS = [coords.lon, coords.lat];
  ui.url.set('run', 'true');
  ui.url.set('lon', COORDS[0]);
  ui.url.set('lat', COORDS[1]);
  renderGraphics(COORDS);
}

/**
 * Handles submit button click.
 */
function handleSubmitClick() {
  renderGraphics(COORDS);
  submitButton.style().set('shown', false);
}

/**
 * Sets URL params.
 */
function setParams() {
  ui.url.set('index', indexSelect.getValue());
  ui.url.set('rgb', rgbSelect.getValue());
  ui.url.set('cloud', cloudSlider.getValue());
  ui.url.set('start', startYearTextbox.getValue());
  ui.url.set('end', endYearTextbox.getValue());
}   
  
/**
 * Show/hide the submit button.
 */
function showSubmitButton() {
  if(CLICKED) {
    submitButton.style().set('shown', true);
  }
}

/**
 * Handles options changes.
 */
function optionChange() {
  showSubmitButton();
  setParams();
}

/**
 * Show/hide the control panel.
 */
var controlShow = false;
function controlButtonHandler() {
  if(controlShow) {
    controlShow = false;
    controlElements.style().set('shown', false);
    controlButton.setLabel('Options ❯');
  } else {
    controlShow = true;
    controlElements.style().set('shown', true);
    controlButton.setLabel('Options ❮');
  }
  
  if(infoShow | controlShow) {
    controlPanel.style().set('width', CONTROL_PANEL_WIDTH);
  } else {
    controlPanel.style().set('width', CONTROL_PANEL_WIDTH_HIDE);
  }
}

/**
 * Show/hide the control panel.
 */
var infoShow = false;
function infoButtonHandler() {
  if(infoShow) {
    infoShow = false;
    infoElements.style().set('shown', false);
    infoButton.setLabel('About ❯');
  } else {
    infoShow = true;
    infoElements.style().set('shown', true);
    infoButton.setLabel('About ❮');
  }
  
  if(infoShow | controlShow) {
    controlPanel.style().set('width', CONTROL_PANEL_WIDTH);
  } else {
    controlPanel.style().set('width', CONTROL_PANEL_WIDTH_HIDE);
  }
}



// #############################################################################
// ### SETUP UI ELEMENTS ###
// #############################################################################

infoElements.add(infoLabel);
infoElements.add(aboutLabel);
infoElements.add(appCodeLink);

controlElements.add(optionsLabel);
controlElements.add(indexPanel);
controlElements.add(rgbPanel);
controlElements.add(startYearPanel);
controlElements.add(endYearPanel);
controlElements.add(cloudPanel);
controlElements.add(submitButton);

controlPanel.add(instr);
controlPanel.add(buttonPanel);
controlPanel.add(infoElements);
controlPanel.add(controlElements);

map.add(controlPanel);

infoButton.onClick(infoButtonHandler);
controlButton.onClick(controlButtonHandler);
rgbSelect.onChange(optionChange);
indexSelect.onChange(optionChange);
startYearTextbox.onChange(optionChange);
endYearTextbox.onChange(optionChange);
durationSlider.onChange(optionChange);
cloudSlider.onChange(optionChange);
submitButton.onClick(handleSubmitClick);
map.onClick(handleMapClick);

map.style().set('cursor', 'crosshair');
map.setOptions('SATELLITE');
map.setControlVisibility(
  {layerList: false, fullscreenControl: false, zoomControl: false});
//map.centerObject(ee.Geometry.Point([-122.91966, 44.24135]), 14);

ui.root.clear();
ui.root.add(mapChartSplitPanel);


if(ui.url.get('run')) {
  CLICKED = true;
  COORDS = [ui.url.get('lon'), ui.url.get('lat')];
  renderGraphics(COORDS);
}