Add ui.Button Google Earth Engine

Question

I just wrote a code for an online application through GEE. The application works when I click on the "run" button within the GEE interface. However, there is no way to run the code in the app interface because there is no "run" button.

Is there any way to add a button to run the code in the app interface?

Answer 1

In your link you have a section labeled PROCESSING STARTS HERE. You could try wrapping your processing steps in a ui.Button object:

var submit = ui.Button({
  label: 'Calculate NDVI',
  onClick: function() {
    var date_start = startDate.getValue();
    var date_end= endDate.getValue();
    // ...
    // The rest of your processing code here
    // Be sure to add your new layer at the end
    // ...
    mapPanel.addLayer(NDVI_annual_recl.select("slope").clip(AOI),BandCompViz);
  }
});

You should also consider whether you want previously calculated images to remain as layers on the map if the user changes the dates and calculates a new NDVI image. Multiple layers on the map can be nice for comparison but can also become cluttered quickly. If you want to clear out the previous layers, add a line at the beginning of the onClick function:

mapPanel.clear() // Or .remove() to specify a single layer

Finally, you'll need to add your new button to the UI panel. You can do this around lines 129-130, where you add the start and end date textboxes.

mainPanel.add(startDate);
mainPanel.add(endDate);
mainPanel.add(submit);

Answer 2

Earth Engine Apps automatically “run the code”. You can see that it's working in your app because the custom left sidebar appears — if the code were not run there would be just a blank map.

If you need a button to take a specific action or reset things, use a ui.Button set up by your code.

In your case, the problem is not that your code is not running. The problem is that it fails partway though. Looking at errors in the browser JavaScript console, I can see that:

Collection.loadTable: Collection asset 'users/jtbsurrey/Collserola' not found.

Therefore, a problem is that you have not made the asset used by the app public. Fix that, and test further.