# Pearson correlation of two 1D array in Earth Engine

This GEE documentation addressed the correlation chart of two bands over a region.

``````// 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);
``````

My question is how to get the value of their correlation? For example how to apply the `ee.Reducer.pearsonsCorrelation()` in this case?

for instance we have an Image collection of landsat 8, pearson correlation test between Band1 and Band2:

``````print(ui.Chart.image.series({
imageCollection: imageCollection.select(['B1','B2']),
region: geometry,
reducer: ee.Reducer.pearsonsCorrelation(),
scale: 30})
``````
``````var geometry = /* color: #d63000 */ee.Geometry.Polygon(
[[[-122.49306916503907, 37.77346675833223],
[-122.48997926025392, 37.738722521119186],
[-122.41101502685548, 37.747953050546485],
[-122.41822480468751, 37.7886622307073]]]);
// Load a Landsat 8 collection for a single path-row.
var collection = ee.ImageCollection('LANDSAT/LC08/C01/T1_TOA')
.filter(ee.Filter.eq('WRS_PATH', 44))
.filter(ee.Filter.eq('WRS_ROW', 34))
.filterDate('2014-01-01', '2020-01-01');
// Compute a median image and display.
var median = collection.median();
Map.setCenter(-122.3578, 37.7726, 12);
Map.addLayer(median, {bands: ['B4', 'B3', 'B2'], max: 0.3}, 'median');

// Make a band correlation chart.
print(ui.Chart.image.series({
imageCollection: collection.select(['B1','B10']),
region: geometry,
reducer: ee.Reducer.pearsonsCorrelation(),
scale: 30}));
``````