Missing data from change map API

[mariaadeliaw]

First of all, thank you for this very useful tool! I am currently trying to do a vegetation cover change analysis in a mining area using LT-GEE. I used the change mapper API to get the year of detection and magnitude of change data from 1999-2019, but when I export the TIFF change image data and analyzed it on QGIS, it seems like it's missing several years of data (for example it didn't detect data from 2001 and 2013). So far I've been trying different parameters for the change parameters for NDVI, but the only difference I got is a different missing year every time I tried a new set of parameters (for example now it's missing 2005 and 2006 instead of 2001 and 2013). I have checked the image collection and I think it already has a complete image from every year. I also have changed the start and end day to one year since the area has no significant seasonal change. May I get any suggestions on what may have caused this and how to solve it? Thank you very much!

This is the code I used

// define collection parameters var startYear = 1999; var endYear = 2019; var startDay = '01-20'; var endDay = '12-20'; var aoi = ee.Geometry(115.61162, -3.38938); var index = 'NDVI'; var maskThese = ['cloud', 'shadow', 'water'];

// define landtrendr parameters var runParams = { maxSegments: 6, spikeThreshold: 0.9, vertexCountOvershoot: 3, preventOneYearRecovery: true, recoveryThreshold: 0.25, pvalThreshold: 0.05, bestModelProportion: 0.75, minObservationsNeeded: 6 };

// define change parameters var changeParams = { delta: 'gain', sort: 'greatest', year: {checked:true, start:1999, end:2019}, mag: {checked:true, value:0, operator:'>', dsnr : true}, dur: {checked:true, value:20, operator:'<'}, preval: {checked:true, value:300, operator:'>'}, mmu: {checked:true, value:11}, };

// load the LandTrendr.js module var ltgee = require('users/emaprlab/public:Modules/LandTrendr.js');

// add index to changeParams object changeParams.index = index;

// run landtrendr var lt = ltgee.runLT(startYear, endYear, startDay, endDay, aoi, index, [], runParams, maskThese);

// get the change map layers var changeImg = ltgee.getChangeMap(lt, changeParams);

var annualSRcollection = ltgee.buildSRcollection(startYear, endYear, startDay, endDay, aoi, maskThese); print(annualSRcollection);

var nClearCollection = ltgee.buildClearPixelCountCollection(startYear, endYear, startDay, endDay, aoi, maskThese); print(nClearCollection);

[clarype]

This is an old one. I will look into it, and see if I can recreate it.