ee.Image.arrayRepeat

  • Image.arrayRepeat() duplicates each pixel's array along a specified axis, creating a new image.

  • The axis parameter determines the dimension along which the repetition occurs (0 or 1 for 1D/2D arrays).

  • The copies parameter specifies the number of times to repeat the array elements along the given axis.

  • Repeating along an existing axis extends the array in that dimension, while repeating along a new axis adds a new dimension to the array.

  • This function is useful for expanding array images or creating patterned data within an image's array structure.

 Repeats each array pixel along the given axis. Each output pixel will have the shape of the input pixel, except length along the repeated axis, which will be multiplied by the number of copies.

UsageReturns
Image.arrayRepeat(axis, copies)Image
ArgumentTypeDetails
this: inputImageImage of array pixels to be repeated.
axisIntegerAxis along which to repeat each pixel's array.
copiesImageNumber of copies of each pixel.

Examples

Code Editor (JavaScript)

// A function to print the array 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');
}

// Create a 1D array image.
var arrayImg1D = ee.Image([0, 1, 2]).toArray();
print('1D array image (pixel)', sampArrImg(arrayImg1D));
// [0, 1, 2]

// Repeat a 1D array along the 0-axis 3 times.
var repeat1DAx0 = arrayImg1D.arrayRepeat(0, 3);
print('1D array repeated 3 times on 0-axis', sampArrImg(repeat1DAx0));
// [0, 1, 2, 0, 1, 2, 0, 1, 2]

// Repeat a 1D array along the 1-axis 3 times (expands the dimensions).
var repeat1DAx1 = arrayImg1D.arrayRepeat(1, 3);
print('1D array repeated 3 times on 1-axis', sampArrImg(repeat1DAx1));
// [[0, 0, 0],
//  [1, 1, 1],
//  [2, 2, 2]]

// Repeat a 2D array along the 0-axis 2 times.
var repeat2DAx0 = repeat1DAx1.arrayRepeat(0, 2);
print('2D array repeated 2 times on 0-axis', sampArrImg(repeat2DAx0));
// [[0, 0, 0],
//  [1, 1, 1],
//  [2, 2, 2],
//  [0, 0, 0],
//  [1, 1, 1],
//  [2, 2, 2]]

// Repeat a 2D array along the 1-axis 2 times.
var repeat2DAx1 = repeat1DAx1.arrayRepeat(1, 2);
print('2D array repeated 2 times on 1-axis', sampArrImg(repeat2DAx1));
// [[0, 0, 0, 0, 0, 0],
//  [1, 1, 1, 1, 1, 1],
//  [2, 2, 2, 2, 2, 2]]

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 the array 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')

# Create a 1D array image.
array_img_1d = ee.Image([0, 1, 2]).toArray()
print('1D array image (pixel):', samp_arr_img(array_img_1d).getInfo())
# [0, 1, 2]

# Repeat a 1D array along the 0-axis 3 times.
repeat_1d_ax0 = array_img_1d.arrayRepeat(0, 3)
print(
    '1D array repeated 3 times on 0-axis:',
    samp_arr_img(repeat_1d_ax0).getInfo()
)
# [0, 1, 2, 0, 1, 2, 0, 1, 2]

# Repeat a 1D array along the 1-axis 3 times (expands the dimensions).
repeat_1d_ax1 = array_img_1d.arrayRepeat(1, 3)
print(
    '1D array repeated 3 times on 1-axis:',
    samp_arr_img(repeat_1d_ax1).getInfo()
)
# [[0, 0, 0],
#  [1, 1, 1],
#  [2, 2, 2]]

# Repeat a 2D array along the 0-axis 2 times.
repeat_2d_ax0 = repeat_1d_ax1.arrayRepeat(0, 2)
print(
    '2D array repeated 2 times on 0-axis:',
    samp_arr_img(repeat_2d_ax0).getInfo()
)
# [[0, 0, 0],
#  [1, 1, 1],
#  [2, 2, 2],
#  [0, 0, 0],
#  [1, 1, 1],
#  [2, 2, 2]]

# Repeat a 2D array along the 1-axis 2 times.
repeat_2d_ax1 = repeat_1d_ax1.arrayRepeat(1, 2)
print(
    '2D array repeated 2 times on 1-axis:',
    samp_arr_img(repeat_2d_ax1).getInfo()
)
# [[0, 0, 0, 0, 0, 0],
#  [1, 1, 1, 1, 1, 1],
#  [2, 2, 2, 2, 2, 2]]