ee.Image.arrayProject

  • arrayProject reduces the dimensionality of an array image by projecting it onto specified axes.

  • Dropped axes must have a maximum length of 1, meaning they can't contain more than one element along that dimension.

  • This operation effectively reshapes the array within each pixel of the image, retaining data from the specified axes.

  • It's useful for operations like concatenating elements from different axes or reducing the complexity of an array image.

 Projects the array in each pixel to a lower dimensional space by specifying the axes to retain. Dropped axes must be at most length 1.

UsageReturns
Image.arrayProject(axes)Image
ArgumentTypeDetails
this: inputImageInput image.
axesListThe axes to retain. Other axes will be discarded and must be at most length 1.

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');
}

// Create a 2D array image with the 0-axis having length 6 and the 1-axis
// having length 1.
var arrayImg2D = ee.Image([0, 1, 2, 3, 4, 5]).toArray().toArray(1);
print('2D array image (pixel)', sampArrImg(arrayImg2D));
// [[0],
//  [1],
//  [2],
//  [3],
//  [4],
//  [5]]

// Project the 2D array to a 1D array, retain the 0-axis (concatenate elements
// from the 1-axis into the 0-axis).
var arrayImg2Dto1D = arrayImg2D.arrayProject([0]);
print('2D array image (pixel)', sampArrImg(arrayImg2Dto1D));
// [0, 1, 2, 3, 4, 5]

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')

# Create a 2D array image with the 0-axis having length 6 and the 1-axis
# having length 1.
array_img_2d = ee.Image([0, 1, 2, 3, 4, 5]).toArray().toArray(1)
print('2D array image (pixel):', samp_arr_img(array_img_2d).getInfo())
# [[0],
#  [1],
#  [2],
#  [3],
#  [4],
#  [5]]

# Project the 2D array to a 1D array, retain the 0-axis (concatenate elements
# from the 1-axis into the 0-axis).
array_img_2d_to_1d = array_img_2d.arrayProject([0])
print('2D array image (pixel):', samp_arr_img(array_img_2d_to_1d).getInfo())
# [0, 1, 2, 3, 4, 5]