Array Data Charts

Arrays represent table data in matrix form. (Learn more about arrays in Earth Engine from the Arrays section). To plot these data, use ui.Chart.array.values(). Both X-data and Y-data are supplied to the constructor as arrays. For example, consider the following script which plots Landsat 8 band correlations for a region in San Francisco:

// Define an arbitrary region of interest.
var sanFrancisco = ee.Geometry.Rectangle([-122.45, 37.74, -122.4, 37.8]);

// Load a Landsat 8 image.
var image = ee.Image('LANDSAT/LC8_L1T_TOA/LC80440342014077LGN00');

// Get a dictionary with band names as keys, pixel lists as values.
var result = image.reduceRegion(ee.Reducer.toList(), sanFrancisco, 120);

// Convert the band data to plot on the y-axis to arrays.
var y1 = ee.Array(result.get('B5'));
var y2 = ee.Array(result.get('B6'));
// Concatenate the y-axis data by stacking the arrays on the 1-axis.
var yValues = ee.Array.cat([y1, y2], 1);

// The band data to plot on the x-axis is a List.
var xValues = result.get('B4');

// Make a band correlation chart.
var chart = ui.Chart.array.values(yValues, 0, xValues)
    .setSeriesNames(['B5', 'B6'])
    .setOptions({
      title: 'LC8 TOA B4 vs. {B5,B6}',
      hAxis: {'title': 'B4'},
      vAxis: {'title': '{B5,B6}'},
      pointSize: 3,
});

// Print the chart.
print(chart);
    

In this example, note that the data to plot on the y-axis are in an Array (yValues) and the x-coordinates of the data are provided in a List (xValues). The second parameter (0) of ui.Chart.array.values() tells Earth Engine along which array axis the chart data vary. The output should look something like Figure 1.

ui.Chart.array.values
Figure 1. Band correlations for a subset of a Landsat 8 scene in San Francisco.

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