OstuMODIS

var geometry = ee.Geometry.Point([-114.25034538171685, 50.91587090557124]);

// can be changed
var otsuMode='sequence'; //'sequence'

var oeel=require('users/OEEL/lib:loadAll')

var modis=ee.ImageCollection("MODIS/006/MOD09GQ").filterDate('2018-01-01','2021-01-01')
var ndvi=modis.map(function(im){return im.addBands(im.normalizedDifference(['sur_refl_b02','sur_refl_b01']))});

var otsuTh=oeel.ImageCollection.OtsuThreshold(ndvi,'nd',otsuMode)
var otsuThCol=oeel.ImageCollection.OtsuThreshold({imageCollection:ndvi, selectBand:'nd', mode:otsuMode, getCoefCollection:true});

var ftC=ee.FeatureCollection(ndvi.map(function(im){return ee.Feature(null,im.reduceRegion(ee.Reducer.mean(), geometry, 250))}))//.filter(ee.Filter.notNull(['nd']));
print(ui.Chart.feature.histogram(ftC, 'nd'))


var ftCol=otsuThCol.map(function(im){return ee.Feature(null,im.reduceRegion(ee.Reducer.mean(), geometry, 250))});

print(ui.Chart.feature.byFeature(ftCol, 'threshold','score').setChartType('ScatterChart'))

var localTh=ee.Number(otsuTh.reduceRegion(ee.Reducer.mean(), geometry, 250).get('threshold'));


var hist=ee.FeatureCollection(ee.Array(ftC.reduceColumns(ee.Reducer.autoHistogram(),['nd']).get('histogram')).toList().map(function(li){ li=ee.List(li);
  return ee.Feature(null,ee.Dictionary.fromLists(['nd','amount','aboveTh'],li.add(ee.Number(li.get(0)).gt(localTh))))}));

print(ui.Chart.feature.groups(hist,'nd', 'amount', 'aboveTh').setChartType('ColumnChart'))


Map.addLayer(otsuTh,{min:-1,max:1},'threshold',false)

print('list of functions used',oeel.refs())