Forcing y-axis range in ui.Chart.image.series()

Question

I am harmonizing Landsat 8 and Sentinel-2 datasets for agricultural mapping purposes. When plotting the results using ui.Chart.image.series function, one graph shows the y-axis starting not at 0. For comparison purposes I need the y-axis on the charts to start at zero. How to adjust the below command to force y-axis to start at zero?

// Plot the fitted model and the original data at the ROI.
print(ui.Chart.image.series(fittedHarmonicboth.select(['fitted','NDVI']), roi, ee.Reducer.mean(), 10)
    .setOptions({
      title: 'Harmonic model: both S2 and L8 values',
      lineWidth: 1,
      pointSize: 3,
}));

Answer 1

Within your options you should add the vAxis.minValue, such as:

print(ui.Chart.image.series(fittedHarmonicboth.select(['fitted','NDVI']), roi, ee.Reducer.mean(), 10)
    .setOptions({
      title: 'Harmonic model: both S2 and L8 values',
      lineWidth: 1,
      pointSize: 3,
      vAxis: {minValue:0},
}));

More options are shown here.

Answer 2

Add the limits with vAxis: {viewWindow: }}

print(ui.Chart.image.series(fittedHarmonicboth.select(['fitted','NDVI']), roi, ee.Reducer.mean(), 10)
    .setOptions({
      title: 'Harmonic model: both S2 and L8 values',
      lineWidth: 1,
      pointSize: 3,
      vAxis: {viewWindow: {min: 0}},
}));