ee.Image.arrayDotProduct

  • Computes the dot product of corresponding 1-D arrays within two input images, resulting in a new image.

  • Each 1-D array represents a band in the input images, and they must have the same length.

  • The dot product calculation is performed element-wise between the arrays in matching bands.

  • The resulting image contains a single band representing the dot product values for each pixel location.

 Computes the dot product of each pair of 1-D arrays in the bands of the input images.

UsageReturns
Image.arrayDotProduct(image2)Image
ArgumentTypeDetails
this: image1ImageFirst array image of 1-D vectors.
image2ImageSecond array image of 1-D vectors.

Examples

Code Editor (JavaScript)

// A function to print arrays for a selected pixel in the following examples.
function sampArrImg(arrImg) {
  var point = ee.Geometry.Point([-121, 42]);
  return arrImg.sample(point, 500).first().get('array');
}

// A 1D array image.
var arrayImg1Da = ee.Image([0, 1, 2]).toArray();
print('1D array image A (pixel)', sampArrImg(arrayImg1Da));
// [0, 1, 2]

// A second 1D array image of the same length.
var arrayImg1Db = ee.Image([3, 4, 5]).toArray();
print('1D array image B (pixel)', sampArrImg(arrayImg1Db));
// [3, 4, 5]

// Calculate the dot product for the two 1D arrays.
var test = arrayImg1Da.arrayDotProduct(arrayImg1Db);
print('A⋅B = 0(3) + 1(4) + 2(5) = ', sampArrImg(test));
// 14

Python setup

See the Python Environment page for information on the Python API and using geemap for interactive development.

import ee
import geemap.core as geemap

Colab (Python)

# A function to print arrays for a selected pixel in the following examples.
def samp_arr_img(arr_img):
  point = ee.Geometry.Point([-121, 42])
  return arr_img.sample(point, 500).first().get('array')

# A 1D array image.
array_img_1d_a = ee.Image([0, 1, 2]).toArray()
print('1D array image A (pixel):', samp_arr_img(array_img_1d_a).getInfo())
# [0, 1, 2]

# A second 1D array image of the same length.
array_img_1d_b = ee.Image([3, 4, 5]).toArray()
print('1D array image B (pixel):', samp_arr_img(array_img_1d_b).getInfo())
# [3, 4, 5]

# Calculate the dot product for the two 1D arrays.
test = array_img_1d_a.arrayDotProduct(array_img_1d_b)
print('A⋅B = 0(3) + 1(4) + 2(5) = ', samp_arr_img(test).getInfo())
# 14