Google Earth Engine to Numpy

Export the the result of your earth engine calculation to an numpy array


The code below imports sentinel-2 satellite imagery.
use the first function do any calculation on the image collection. The second function will get the latitude, longitude and value of each pixel. The third function will convert the 1 dimensional array into a 2 dimensional image.

import ee
import numpy as np
from osgeo import gdal
from osgeo import osr
import time

# init the ee object

# Define the roi
area = ee.Geometry.Polygon([[105.4084512289977,12.960956032145036],\

# define the image
collection = ee.ImageCollection("COPERNICUS/S2").filterBounds(area)\
									  .select(['B8', 'B4'])

print(" number of image: ",collection.size().getInfo())

# perform any calculation on the image collection here
def anyFunction(img):
	ndvi = ee.Image(img.normalizedDifference(['B8', 'B4'])).rename(["ndvi"])
	return ndvi

# export the latitude, longitude and array
def LatLonImg(img):
	img = img.addBands(ee.Image.pixelLonLat())

	img = img.reduceRegion(reducer=ee.Reducer.toList(),\

 	data = np.array((ee.Array(img.get("result")).getInfo()))
	lats = np.array((ee.Array(img.get("latitude")).getInfo()))
	lons = np.array((ee.Array(img.get("longitude")).getInfo()))
	return lats, lons, data

# covert the lat, lon and array into an image
def toImage(lats,lons,data):

	# get the unique coordinates
	uniqueLats = np.unique(lats)
	uniqueLons = np.unique(lons)

	# get number of columns and rows from coordinates
	ncols = len(uniqueLons)
	nrows = len(uniqueLats)

	# determine pixelsizes
	ys = uniqueLats[1] - uniqueLats[0]
	xs = uniqueLons[1] - uniqueLons[0]

	# create an array with dimensions of image
	arr = np.zeros([nrows, ncols], np.float32) #-9999

	# fill the array with values
	counter =0
	for y in range(0,len(arr),1):
		for x in range(0,len(arr[0]),1):
			if lats[counter] == uniqueLats[y] and lons[counter] == uniqueLons[x] and counter < len(lats)-1:
				arr[len(uniqueLats)-1-y,x] = data[counter] # we start from lower left corner
	return arr

# map over the image collection
myCollection  =

# get the median
result = ee.Image(myCollection.median()).rename(['result'])

# get the lon, lat and result as 1d array
lat, lon, data = LatLonImg(result)

# 1d to 2d array
image  = toImage(lat,lon,data)

# in case you want to plot the image
import matplotlib.pyplot as plt

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s