GEE：如何理解FUNCTION 'ui.Chart.image.series'中的参数'SCALE'？

Question

print(ui.Chart.image.series(col, geometry,ee.Reducer.mean(),20).setOptions({
title: 'TimeSeries analysis',
lineWidth: 1,
pointSize: 3 }));

print(ui.Chart.image.series(col, geometry,ee.Reducer.mean(),200).setOptions({
title: 'TimeSeries analysis',
lineWidth: 1,
pointSize: 3 }));

when I set the parameter scale in different values, the chart is different(I mean at the same time while the value is different), so I want to know the meaning of the "scale" parameter and ee.Reducer parameter? I try to find the meaning in the GEE guide help, but can't understand.

Answer 1

Scale refers to the pixel resolution used to analyse the image. The larger the scale the more aggregated the pixels will be, thus outputting different results. Say you are analyzing a vegetation index on a plot of land. If you want to know the max value, analyzing it by pixels of 20 m by 20 m will lead to a different result than if you analysed it in pieces of 1000 m by 1000 m. The smaller the resolution, the more accurate the results, but the slower the calculation and vice-versa.

More info on this here https://developers.google.com/earth-engine/guides/scale