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From the following NDVI collection, I want to keep only the observations with Good Quality (equal to zero). I try to do this with the SummaryQA but I get "Pattern 'SummaryQA' did not match any bands". My attempt:

var geometry = /* color: #0b4a8b */ee.Geometry.Polygon(
  [[[110.49279650854476, 39.617434795765476],
    [111.02014025854476, 36.57484614339866],
    [117.48010119604476, 36.92695433193529],
    [117.43615588354476, 40.35816406661026]]]),modis =ee.ImageCollection("MODIS/006/MOD13Q1")
    .filterBounds(geometry)
    .map(function(image){return image.clip(geometry)}) 
    .filter(ee.Filter.calendarRange(4,7,'month'));
    var modisNDVI = modis.select("NDVI");

    var maskQA = function(image) {
      return image.updateMask(image.select("SummaryQA").eq(0));
    };
    var best = modisNDVI.map(maskQA)
    print(best)

1 Answer 1

1

When you select NDVI band, you are only keeping that band, so you cannot use other band.

Replace

var modisNDVI = modis.select("NDVI");

with

var modisNDVI = modis.select(["NDVI", "SummaryQA"]);
4
  • Thank you @Rodrigo. In this case though, when I try to perform a batch download of the best collection, I get "Failed to decode JSON. Error: Type must be one of: [compoundvalue, date, bytes, point, dictionary, function, invocation, multipoint, linestring, linearring, multilinestring, polygon, multipolygon, geometrycollection, argumentref, valueref]. Object: "FeatureCollection"."
    – foo
    Jan 21, 2019 at 13:39
  • how are you trying to batch download? Jan 21, 2019 at 14:07
  • var batch = require('users/fitoprincipe/geetools:batch') batch.Download.ImageCollection.toDrive(best, "m_ar", {scale:250,region: geometry.getInfo()});
    – foo
    Jan 21, 2019 at 14:08
  • try with geometry instead of geometry.getInfo() Jan 21, 2019 at 15:31

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