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/LC08/C01/T1_TOA/LC08_044034_20140318'); // 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.
