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Python

"""This module contains all the functions needed to download the satellite images from the Google
Earth Engine Server
Author: Kilian Vos, Water Research Laboratory, University of New South Wales
"""
# load modules
import os
import numpy as np
import matplotlib.pyplot as plt
import pdb
# earth engine modules
import ee
from urllib.request import urlretrieve
import zipfile
import copy
from coastsat import gdal_merge
# additional modules
from datetime import datetime
import pytz
import pickle
import skimage.morphology as morphology
# own modules
from coastsat import SDS_preprocess, SDS_tools
np.seterr(all='ignore') # raise/ignore divisions by 0 and nans
# initialise connection with GEE server
ee.Initialize()
def download_tif(image, polygon, bandsId, filepath):
"""
Downloads a .TIF image from the ee server and stores it in a temp file
Arguments:
-----------
image: ee.Image
Image object to be downloaded
polygon: list
polygon containing the lon/lat coordinates to be extracted
longitudes in the first column and latitudes in the second column
bandsId: list of dict
list of bands to be downloaded
filepath: location where the temporary file should be saved
"""
url = ee.data.makeDownloadUrl(ee.data.getDownloadId({
'image': image.serialize(),
'region': polygon,
'bands': bandsId,
'filePerBand': 'false',
'name': 'data',
}))
local_zip, headers = urlretrieve(url)
with zipfile.ZipFile(local_zip) as local_zipfile:
return local_zipfile.extract('data.tif', filepath)
def retrieve_images(inputs):
"""
Downloads all images from Landsat 5, Landsat 7, Landsat 8 and Sentinel-2 covering the area of
interest and acquired between the specified dates.
The downloaded images are in .TIF format and organised in subfolders, divided by satellite
mission and pixel resolution.
KV WRL 2018
Arguments:
-----------
inputs: dict
dictionnary that contains the following fields:
'sitename': str
String containig the name of the site
'polygon': list
polygon containing the lon/lat coordinates to be extracted,
longitudes in the first column and latitudes in the second column,
there are 5 pairs of lat/lon with the fifth point equal to the first point.
e.g. [[[151.3, -33.7],[151.4, -33.7],[151.4, -33.8],[151.3, -33.8],
[151.3, -33.7]]]
'dates': list of str
list that contains 2 strings with the initial and final dates in format 'yyyy-mm-dd'
e.g. ['1987-01-01', '2018-01-01']
'sat_list': list of str
list that contains the names of the satellite missions to include
e.g. ['L5', 'L7', 'L8', 'S2']
'filepath_data': str
Filepath to the directory where the images are downloaded
Returns:
-----------
metadata: dict
contains the information about the satellite images that were downloaded: filename,
georeferencing accuracy and image coordinate reference system
"""
# read inputs dictionnary
sitename = inputs['sitename']
polygon = inputs['polygon']
dates = inputs['dates']
sat_list= inputs['sat_list']
filepath_data = inputs['filepath']
# format in which the images are downloaded
suffix = '.tif'
# initialize metadata dictionnary (stores information about each image)
metadata = dict([])
# create a new directory for this site
if not os.path.exists(os.path.join(filepath_data,sitename)):
os.makedirs(os.path.join(filepath_data,sitename))
print('Downloading images:')
#=============================================================================================#
# download L5 images
#=============================================================================================#
if 'L5' in sat_list or 'Landsat5' in sat_list:
satname = 'L5'
# create a subfolder to store L5 images
filepath = os.path.join(filepath_data, sitename, satname, '30m')
filepath_meta = os.path.join(filepath_data, sitename, satname, 'meta')
if not os.path.exists(filepath):
os.makedirs(filepath)
if not os.path.exists(filepath_meta):
os.makedirs(filepath_meta)
# Landsat 5 collection
input_col = ee.ImageCollection('LANDSAT/LT05/C01/T1_TOA')
# filter by location and dates
flt_col = input_col.filterBounds(ee.Geometry.Polygon(polygon)).filterDate(dates[0],dates[1])
# get all images in the filtered collection
im_all = flt_col.getInfo().get('features')
# remove very cloudy images (>95% cloud)
cloud_cover = [_['properties']['CLOUD_COVER'] for _ in im_all]
if np.any([_ > 95 for _ in cloud_cover]):
idx_delete = np.where([_ > 95 for _ in cloud_cover])[0]
im_col = [x for k,x in enumerate(im_all) if k not in idx_delete]
else:
im_col = im_all
n_img = len(im_col)
# print how many images there are
print('%s: %d images'%(satname,n_img))
# loop trough images
timestamps = []
acc_georef = []
filenames = []
all_names = []
im_epsg = []
for i in range(n_img):
# find each image in ee database
im = ee.Image(im_col[i]['id'])
# read metadata
im_dic = im_col[i]
# get bands
im_bands = im_dic['bands']
# get time of acquisition (UNIX time)
t = im_dic['properties']['system:time_start']
# convert to datetime
im_timestamp = datetime.fromtimestamp(t/1000, tz=pytz.utc)
timestamps.append(im_timestamp)
im_date = im_timestamp.strftime('%Y-%m-%d-%H-%M-%S')
# get EPSG code of reference system
im_epsg.append(int(im_dic['bands'][0]['crs'][5:]))
# get geometric accuracy
if 'GEOMETRIC_RMSE_MODEL' in im_dic['properties'].keys():
acc_georef.append(im_dic['properties']['GEOMETRIC_RMSE_MODEL'])
else:
acc_georef.append(12) # default value of accuracy (RMSE = 12m)
# delete dimensions key from dictionnary, otherwise the entire image is extracted
for j in range(len(im_bands)): del im_bands[j]['dimensions']
# bands for L5
ms_bands = [im_bands[0], im_bands[1], im_bands[2], im_bands[3], im_bands[4], im_bands[7]]
# filenames for the images
filename = im_date + '_' + satname + '_' + sitename + suffix
# if two images taken at the same date add 'dup' in the name (duplicate)
if any(filename in _ for _ in all_names):
filename = im_date + '_' + satname + '_' + sitename + '_dup' + suffix
all_names.append(filename)
filenames.append(filename)
# download .TIF image
local_data = download_tif(im, polygon, ms_bands, filepath)
# update filename
try:
os.rename(local_data, os.path.join(filepath, filename))
except:
os.remove(os.path.join(filepath, filename))
os.rename(local_data, os.path.join(filepath, filename))
# write metadata in .txt file
filename_txt = filename.replace('.tif','')
metadict = {'filename':filename,'acc_georef':acc_georef[i],
'epsg':im_epsg[i]}
with open(os.path.join(filepath_meta,filename_txt + '.txt'), 'w') as f:
for key in metadict.keys():
f.write('%s\t%s\n'%(key,metadict[key]))
print('\r%d%%' % (int(((i+1)/n_img)*100)), end='')
print('')
# sort metadata (downloaded images are sorted by date in directory)
timestamps_sorted = sorted(timestamps)
idx_sorted = sorted(range(len(timestamps)), key=timestamps.__getitem__)
acc_georef_sorted = [acc_georef[j] for j in idx_sorted]
filenames_sorted = [filenames[j] for j in idx_sorted]
im_epsg_sorted = [im_epsg[j] for j in idx_sorted]
# save into dict
metadata[satname] = {'dates':timestamps_sorted, 'acc_georef':acc_georef_sorted,
'epsg':im_epsg_sorted, 'filenames':filenames_sorted}
#=============================================================================================#
# download L7 images
#=============================================================================================#
if 'L7' in sat_list or 'Landsat7' in sat_list:
satname = 'L7'
# create subfolders (one for 30m multispectral bands and one for 15m pan bands)
filepath = os.path.join(filepath_data, sitename, 'L7')
filepath_pan = os.path.join(filepath, 'pan')
filepath_ms = os.path.join(filepath, 'ms')
filepath_meta = os.path.join(filepath, 'meta')
if not os.path.exists(filepath_pan):
os.makedirs(filepath_pan)
if not os.path.exists(filepath_ms):
os.makedirs(filepath_ms)
if not os.path.exists(filepath_meta):
os.makedirs(filepath_meta)
# landsat 7 collection
input_col = ee.ImageCollection('LANDSAT/LE07/C01/T1_RT_TOA')
# filter by location and dates
flt_col = input_col.filterBounds(ee.Geometry.Polygon(polygon)).filterDate(dates[0],dates[1])
# get all images in the filtered collection
im_all = flt_col.getInfo().get('features')
# remove very cloudy images (>95% cloud)
cloud_cover = [_['properties']['CLOUD_COVER'] for _ in im_all]
if np.any([_ > 95 for _ in cloud_cover]):
idx_delete = np.where([_ > 95 for _ in cloud_cover])[0]
im_col = [x for k,x in enumerate(im_all) if k not in idx_delete]
else:
im_col = im_all
n_img = len(im_col)
# print how many images there are
print('%s: %d images'%(satname,n_img))
# loop trough images
timestamps = []
acc_georef = []
filenames = []
all_names = []
im_epsg = []
for i in range(n_img):
# find each image in ee database
im = ee.Image(im_col[i]['id'])
# read metadata
im_dic = im_col[i]
# get bands
im_bands = im_dic['bands']
# get time of acquisition (UNIX time)
t = im_dic['properties']['system:time_start']
# convert to datetime
im_timestamp = datetime.fromtimestamp(t/1000, tz=pytz.utc)
timestamps.append(im_timestamp)
im_date = im_timestamp.strftime('%Y-%m-%d-%H-%M-%S')
# get EPSG code of reference system
im_epsg.append(int(im_dic['bands'][0]['crs'][5:]))
# get geometric accuracy
if 'GEOMETRIC_RMSE_MODEL' in im_dic['properties'].keys():
acc_georef.append(im_dic['properties']['GEOMETRIC_RMSE_MODEL'])
else:
acc_georef.append(12) # default value of accuracy (RMSE = 12m)
# delete dimensions key from dictionnary, otherwise the entire image is extracted
for j in range(len(im_bands)): del im_bands[j]['dimensions']
# bands for L7
pan_band = [im_bands[8]]
ms_bands = [im_bands[0], im_bands[1], im_bands[2], im_bands[3], im_bands[4], im_bands[9]]
# filenames for the images
filename_pan = im_date + '_' + satname + '_' + sitename + '_pan' + suffix
filename_ms = im_date + '_' + satname + '_' + sitename + '_ms' + suffix
# if two images taken at the same date add 'dup' in the name
if any(filename_pan in _ for _ in all_names):
filename_pan = im_date + '_' + satname + '_' + sitename + '_pan' + '_dup' + suffix
filename_ms = im_date + '_' + satname + '_' + sitename + '_ms' + '_dup' + suffix
all_names.append(filename_pan)
filenames.append(filename_pan)
# download .TIF image
local_data_pan = download_tif(im, polygon, pan_band, filepath_pan)
local_data_ms = download_tif(im, polygon, ms_bands, filepath_ms)
# update filename
try:
os.rename(local_data_pan, os.path.join(filepath_pan, filename_pan))
except:
os.remove(os.path.join(filepath_pan, filename_pan))
os.rename(local_data_pan, os.path.join(filepath_pan, filename_pan))
try:
os.rename(local_data_ms, os.path.join(filepath_ms, filename_ms))
except:
os.remove(os.path.join(filepath_ms, filename_ms))
os.rename(local_data_ms, os.path.join(filepath_ms, filename_ms))
# write metadata in .txt file
filename_txt = filename_pan.replace('_pan','').replace('.tif','')
metadict = {'filename':filename_pan,'acc_georef':acc_georef[i],
'epsg':im_epsg[i]}
with open(os.path.join(filepath_meta,filename_txt + '.txt'), 'w') as f:
for key in metadict.keys():
f.write('%s\t%s\n'%(key,metadict[key]))
print('\r%d%%' % (int(((i+1)/n_img)*100)), end='')
print('')
# sort metadata (dowloaded images are sorted by date in directory)
timestamps_sorted = sorted(timestamps)
idx_sorted = sorted(range(len(timestamps)), key=timestamps.__getitem__)
acc_georef_sorted = [acc_georef[j] for j in idx_sorted]
filenames_sorted = [filenames[j] for j in idx_sorted]
im_epsg_sorted = [im_epsg[j] for j in idx_sorted]
# save into dict
metadata[satname] = {'dates':timestamps_sorted, 'acc_georef':acc_georef_sorted,
'epsg':im_epsg_sorted, 'filenames':filenames_sorted}
#=============================================================================================#
# download L8 images
#=============================================================================================#
if 'L8' in sat_list or 'Landsat8' in sat_list:
satname = 'L8'
# create subfolders (one for 30m multispectral bands and one for 15m pan bands)
filepath = os.path.join(filepath_data, sitename, 'L8')
filepath_pan = os.path.join(filepath, 'pan')
filepath_ms = os.path.join(filepath, 'ms')
filepath_meta = os.path.join(filepath, 'meta')
if not os.path.exists(filepath_pan):
os.makedirs(filepath_pan)
if not os.path.exists(filepath_ms):
os.makedirs(filepath_ms)
if not os.path.exists(filepath_meta):
os.makedirs(filepath_meta)
# landsat 8 collection
input_col = ee.ImageCollection('LANDSAT/LC08/C01/T1_RT_TOA')
# filter by location and dates
flt_col = input_col.filterBounds(ee.Geometry.Polygon(polygon)).filterDate(dates[0],dates[1])
# get all images in the filtered collection
im_all = flt_col.getInfo().get('features')
# remove very cloudy images (>95% cloud)
cloud_cover = [_['properties']['CLOUD_COVER'] for _ in im_all]
if np.any([_ > 95 for _ in cloud_cover]):
idx_delete = np.where([_ > 95 for _ in cloud_cover])[0]
im_col = [x for k,x in enumerate(im_all) if k not in idx_delete]
else:
im_col = im_all
n_img = len(im_col)
# print how many images there are
print('%s: %d images'%(satname,n_img))
# loop trough images
timestamps = []
acc_georef = []
filenames = []
all_names = []
im_epsg = []
for i in range(n_img):
# find each image in ee database
im = ee.Image(im_col[i]['id'])
# read metadata
im_dic = im_col[i]
# get bands
im_bands = im_dic['bands']
# get time of acquisition (UNIX time)
t = im_dic['properties']['system:time_start']
# convert to datetime
im_timestamp = datetime.fromtimestamp(t/1000, tz=pytz.utc)
timestamps.append(im_timestamp)
im_date = im_timestamp.strftime('%Y-%m-%d-%H-%M-%S')
# get EPSG code of reference system
im_epsg.append(int(im_dic['bands'][0]['crs'][5:]))
# get geometric accuracy
if 'GEOMETRIC_RMSE_MODEL' in im_dic['properties'].keys():
acc_georef.append(im_dic['properties']['GEOMETRIC_RMSE_MODEL'])
else:
acc_georef.append(12) # default value of accuracy (RMSE = 12m)
# delete dimensions key from dictionnary, otherwise the entire image is extracted
for j in range(len(im_bands)): del im_bands[j]['dimensions']
# bands for L8
pan_band = [im_bands[7]]
ms_bands = [im_bands[1], im_bands[2], im_bands[3], im_bands[4], im_bands[5], im_bands[11]]
# filenames for the images
filename_pan = im_date + '_' + satname + '_' + sitename + '_pan' + suffix
filename_ms = im_date + '_' + satname + '_' + sitename + '_ms' + suffix
# if two images taken at the same date add 'dup' in the name
if any(filename_pan in _ for _ in all_names):
filename_pan = im_date + '_' + satname + '_' + sitename + '_pan' + '_dup' + suffix
filename_ms = im_date + '_' + satname + '_' + sitename + '_ms' + '_dup' + suffix
all_names.append(filename_pan)
filenames.append(filename_pan)
# download .TIF image
local_data_pan = download_tif(im, polygon, pan_band, filepath_pan)
local_data_ms = download_tif(im, polygon, ms_bands, filepath_ms)
# update filename
try:
os.rename(local_data_pan, os.path.join(filepath_pan, filename_pan))
except:
os.remove(os.path.join(filepath_pan, filename_pan))
os.rename(local_data_pan, os.path.join(filepath_pan, filename_pan))
try:
os.rename(local_data_ms, os.path.join(filepath_ms, filename_ms))
except:
os.remove(os.path.join(filepath_ms, filename_ms))
os.rename(local_data_ms, os.path.join(filepath_ms, filename_ms))
# write metadata in .txt file
filename_txt = filename_pan.replace('_pan','').replace('.tif','')
metadict = {'filename':filename_pan,'acc_georef':acc_georef[i],
'epsg':im_epsg[i]}
with open(os.path.join(filepath_meta,filename_txt + '.txt'), 'w') as f:
for key in metadict.keys():
f.write('%s\t%s\n'%(key,metadict[key]))
print('\r%d%%' % (int(((i+1)/n_img)*100)), end='')
print('')
# sort metadata (dowloaded images are sorted by date in directory)
timestamps_sorted = sorted(timestamps)
idx_sorted = sorted(range(len(timestamps)), key=timestamps.__getitem__)
acc_georef_sorted = [acc_georef[j] for j in idx_sorted]
filenames_sorted = [filenames[j] for j in idx_sorted]
im_epsg_sorted = [im_epsg[j] for j in idx_sorted]
metadata[satname] = {'dates':timestamps_sorted, 'acc_georef':acc_georef_sorted,
'epsg':im_epsg_sorted, 'filenames':filenames_sorted}
#=============================================================================================#
# download S2 images
#=============================================================================================#
if 'S2' in sat_list or 'Sentinel2' in sat_list:
satname = 'S2'
# create subfolders for the 10m, 20m and 60m multipectral bands
filepath = os.path.join(filepath_data, sitename, 'S2')
if not os.path.exists(os.path.join(filepath, '10m')):
os.makedirs(os.path.join(filepath, '10m'))
if not os.path.exists(os.path.join(filepath, '20m')):
os.makedirs(os.path.join(filepath, '20m'))
if not os.path.exists(os.path.join(filepath, '60m')):
os.makedirs(os.path.join(filepath, '60m'))
filepath_meta = os.path.join(filepath, 'meta')
if not os.path.exists(filepath_meta):
os.makedirs(filepath_meta)
# Sentinel2 collection
input_col = ee.ImageCollection('COPERNICUS/S2')
# filter by location and dates
flt_col = input_col.filterBounds(ee.Geometry.Polygon(polygon)).filterDate(dates[0],dates[1])
# get all images in the filtered collection
im_all = flt_col.getInfo().get('features')
# remove duplicates in the collection (there are many in S2 collection)
timestamps = [datetime.fromtimestamp(_['properties']['system:time_start']/1000,
tz=pytz.utc) for _ in im_all]
# utm zone projection
utm_zones = np.array([int(_['bands'][0]['crs'][5:]) for _ in im_all])
utm_zone_selected = np.max(np.unique(utm_zones))
# find the images that were acquired at the same time but have different utm zones
idx_all = np.arange(0,len(im_all),1)
idx_covered = np.ones(len(im_all)).astype(bool)
idx_delete = []
i = 0
while 1:
same_time = np.abs([(timestamps[i]-_).total_seconds() for _ in timestamps]) < 60*60*24
idx_same_time = np.where(same_time)[0]
same_utm = utm_zones == utm_zone_selected
idx_temp = np.where([same_time[j] == True and same_utm[j] == False for j in idx_all])[0]
idx_keep = idx_same_time[[_ not in idx_temp for _ in idx_same_time ]]
# if more than 2 images with same date and same utm, drop the last ones
if len(idx_keep) > 2:
idx_temp = np.append(idx_temp,idx_keep[-(len(idx_keep)-2):])
for j in idx_temp:
idx_delete.append(j)
idx_covered[idx_same_time] = False
if np.any(idx_covered):
i = np.where(idx_covered)[0][0]
else:
break
# update the collection by deleting all those images that have same timestamp and different
# utm projection
im_all_updated = [x for k,x in enumerate(im_all) if k not in idx_delete]
# remove very cloudy images (>95% cloud)
cloud_cover = [_['properties']['CLOUDY_PIXEL_PERCENTAGE'] for _ in im_all_updated]
if np.any([_ > 95 for _ in cloud_cover]):
idx_delete = np.where([_ > 95 for _ in cloud_cover])[0]
im_col = [x for k,x in enumerate(im_all_updated) if k not in idx_delete]
else:
im_col = im_all_updated
n_img = len(im_col)
# print how many images there are
print('%s: %d images'%(satname,n_img))
# loop trough images
timestamps = []
acc_georef = []
filenames = []
all_names = []
im_epsg = []
for i in range(n_img):
# find each image in ee database
im = ee.Image(im_col[i]['id'])
# read metadata
im_dic = im_col[i]
# get bands
im_bands = im_dic['bands']
# get time of acquisition (UNIX time)
t = im_dic['properties']['system:time_start']
# convert to datetime
im_timestamp = datetime.fromtimestamp(t/1000, tz=pytz.utc)
im_date = im_timestamp.strftime('%Y-%m-%d-%H-%M-%S')
# delete dimensions key from dictionnary, otherwise the entire image is extracted
for j in range(len(im_bands)): del im_bands[j]['dimensions']
# bands for S2
bands10 = [im_bands[1], im_bands[2], im_bands[3], im_bands[7]]
bands20 = [im_bands[11]]
bands60 = [im_bands[15]]
# filenames for images
filename10 = im_date + '_' + satname + '_' + sitename + '_' + '10m' + suffix
filename20 = im_date + '_' + satname + '_' + sitename + '_' + '20m' + suffix
filename60 = im_date + '_' + satname + '_' + sitename + '_' + '60m' + suffix
# if two images taken at the same date skip the second image (they are the same)
if any(filename10 in _ for _ in all_names):
filename10 = filename10[:filename10.find('.')] + '_dup' + suffix
filename20 = filename20[:filename20.find('.')] + '_dup' + suffix
filename60 = filename60[:filename60.find('.')] + '_dup' + suffix
all_names.append(filename10)
filenames.append(filename10)
# download .TIF image and update filename
local_data = download_tif(im, polygon, bands10, os.path.join(filepath, '10m'))
try:
os.rename(local_data, os.path.join(filepath, '10m', filename10))
except:
os.remove(os.path.join(filepath, '10m', filename10))
os.rename(local_data, os.path.join(filepath, '10m', filename10))
local_data = download_tif(im, polygon, bands20, os.path.join(filepath, '20m'))
try:
os.rename(local_data, os.path.join(filepath, '20m', filename20))
except:
os.remove(os.path.join(filepath, '20m', filename20))
os.rename(local_data, os.path.join(filepath, '20m', filename20))
local_data = download_tif(im, polygon, bands60, os.path.join(filepath, '60m'))
try:
os.rename(local_data, os.path.join(filepath, '60m', filename60))
except:
os.remove(os.path.join(filepath, '60m', filename60))
os.rename(local_data, os.path.join(filepath, '60m', filename60))
# save timestamp, epsg code and georeferencing accuracy (1 if passed 0 if not passed)
timestamps.append(im_timestamp)
im_epsg.append(int(im_dic['bands'][0]['crs'][5:]))
# Sentinel-2 products don't provide a georeferencing accuracy (RMSE as in Landsat)
# but they have a flag indicating if the geometric quality control was passed or failed
# if passed a value of 1 is stored if failed a value of -1 is stored in the metadata
if 'GEOMETRIC_QUALITY_FLAG' in im_dic['properties'].keys():
if im_dic['properties']['GEOMETRIC_QUALITY_FLAG'] == 'PASSED':
acc_georef.append(1)
else:
acc_georef.append(-1)
elif 'quality_check' in im_dic['properties'].keys():
if im_dic['properties']['quality_check'] == 'PASSED':
acc_georef.append(1)
else:
acc_georef.append(-1)
else:
acc_georef.append(-1)
# write metadata in .txt file
filename_txt = filename10.replace('_10m','').replace('.tif','')
metadict = {'filename':filename10,'acc_georef':acc_georef[i],
'epsg':im_epsg[i]}
with open(os.path.join(filepath_meta,filename_txt + '.txt'), 'w') as f:
for key in metadict.keys():
f.write('%s\t%s\n'%(key,metadict[key]))
print('\r%d%%' % (int(((i+1)/n_img)*100)), end='')
print('')
# sort metadata (dowloaded images are sorted by date in directory)
timestamps_sorted = sorted(timestamps)
idx_sorted = sorted(range(len(timestamps)), key=timestamps.__getitem__)
acc_georef_sorted = [acc_georef[j] for j in idx_sorted]
filenames_sorted = [filenames[j] for j in idx_sorted]
im_epsg_sorted = [im_epsg[j] for j in idx_sorted]
metadata[satname] = {'dates':timestamps_sorted, 'acc_georef':acc_georef_sorted,
'epsg':im_epsg_sorted, 'filenames':filenames_sorted}
# merge overlapping images (necessary only if the polygon is at the boundary of an image)
if 'S2' in metadata.keys():
metadata = merge_overlapping_images(metadata,inputs)
# save metadata dict
filepath = os.path.join(filepath_data, sitename)
with open(os.path.join(filepath, sitename + '_metadata' + '.pkl'), 'wb') as f:
pickle.dump(metadata, f)
return metadata
def merge_overlapping_images(metadata,inputs):
"""
When the area of interest is located at the boundary between 2 images, there will be overlap
between the 2 images and both will be downloaded from Google Earth Engine. This function
merges the 2 images, so that the area of interest is covered by only 1 image.
KV WRL 2018
Arguments:
-----------
metadata: dict
contains all the information about the satellite images that were downloaded
inputs: dict
dictionnary that contains the following fields:
'sitename': str
String containig the name of the site
'polygon': list
polygon containing the lon/lat coordinates to be extracted,
longitudes in the first column and latitudes in the second column,
there are 5 pairs of lat/lon with the fifth point equal to the first point.
e.g. [[[151.3, -33.7],[151.4, -33.7],[151.4, -33.8],[151.3, -33.8],
[151.3, -33.7]]]
'dates': list of str
list that contains 2 strings with the initial and final dates in format 'yyyy-mm-dd'
e.g. ['1987-01-01', '2018-01-01']
'sat_list': list of str
list that contains the names of the satellite missions to include
e.g. ['L5', 'L7', 'L8', 'S2']
'filepath_data': str
Filepath to the directory where the images are downloaded
Returns:
-----------
metadata_updated: dict
updated metadata with the information of the merged images
"""
# only for Sentinel-2 at this stage (not sure if this is needed for Landsat images)
sat = 'S2'
filepath = os.path.join(inputs['filepath'], inputs['sitename'])
# find the images that are overlapping (same date in S2 filenames)
filenames = metadata[sat]['filenames']
filenames_copy = filenames.copy()
# loop through all the filenames and find the pairs of overlapping images (same date and time of acquisition)
pairs = []
for i,fn in enumerate(filenames):
filenames_copy[i] = []
# find duplicate
boolvec = [fn[:22] == _[:22] for _ in filenames_copy]
if np.any(boolvec):
idx_dup = np.where(boolvec)[0][0]
if len(filenames[i]) > len(filenames[idx_dup]):
pairs.append([idx_dup,i])
else:
pairs.append([i,idx_dup])
# for each pair of images, merge them into one complete image
for i,pair in enumerate(pairs):
fn_im = []
for index in range(len(pair)):
# read image
fn_im.append([os.path.join(filepath, 'S2', '10m', filenames[pair[index]]),
os.path.join(filepath, 'S2', '20m', filenames[pair[index]].replace('10m','20m')),
os.path.join(filepath, 'S2', '60m', filenames[pair[index]].replace('10m','60m')),
os.path.join(filepath, 'S2', 'meta', filenames[pair[index]].replace('_10m','').replace('.tif','.txt'))])
im_ms, georef, cloud_mask, im_extra, im_QA, im_nodata = SDS_preprocess.preprocess_single(fn_im[index], sat, False)
# in Sentinel2 images close to the edge of the image there are some artefacts,
# that are squares with constant pixel intensities. They need to be masked in the
# raster (GEOTIFF). It can be done using the image standard deviation, which
# indicates values close to 0 for the artefacts.
# First mask the 10m bands
if len(im_ms) > 0:
im_std = SDS_tools.image_std(im_ms[:,:,0],1)
im_binary = np.logical_or(im_std < 1e-6, np.isnan(im_std))
mask = morphology.dilation(im_binary, morphology.square(3))
for k in range(im_ms.shape[2]):
im_ms[mask,k] = np.nan
SDS_tools.mask_raster(fn_im[index][0], mask)
# Then mask the 20m band
im_std = SDS_tools.image_std(im_extra,1)
im_binary = np.logical_or(im_std < 1e-6, np.isnan(im_std))
mask = morphology.dilation(im_binary, morphology.square(3))
im_extra[mask] = np.nan
SDS_tools.mask_raster(fn_im[index][1], mask)
else:
continue
# make a figure for quality control
# plt.figure()
# plt.subplot(221)
# plt.imshow(im_ms[:,:,[2,1,0]])
# plt.title('imRGB')
# plt.subplot(222)
# plt.imshow(im20, cmap='gray')
# plt.title('im20')
# plt.subplot(223)
# plt.imshow(imQA, cmap='gray')
# plt.title('imQA')
# plt.subplot(224)
# plt.title(fn_im[index][0][-30:])
# merge masked 10m bands
fn_merged = os.path.join(os.getcwd(), 'merged.tif')
gdal_merge.main(['', '-o', fn_merged, '-n', '0', fn_im[0][0], fn_im[1][0]])
os.chmod(fn_im[0][0], 0o777)
os.remove(fn_im[0][0])
os.chmod(fn_im[1][0], 0o777)
os.remove(fn_im[1][0])
os.rename(fn_merged, fn_im[0][0])
# merge masked 20m band (SWIR band)
fn_merged = os.path.join(os.getcwd(), 'merged.tif')
gdal_merge.main(['', '-o', fn_merged, '-n', '0', fn_im[0][1], fn_im[1][1]])
os.chmod(fn_im[0][1], 0o777)
os.remove(fn_im[0][1])
os.chmod(fn_im[1][1], 0o777)
os.remove(fn_im[1][1])
os.rename(fn_merged, fn_im[0][1])
# merge QA band (60m band)
fn_merged = os.path.join(os.getcwd(), 'merged.tif')
gdal_merge.main(['', '-o', fn_merged, '-n', 'nan', fn_im[0][2], fn_im[1][2]])
os.chmod(fn_im[0][2], 0o777)
os.remove(fn_im[0][2])
os.chmod(fn_im[1][2], 0o777)
os.remove(fn_im[1][2])
os.rename(fn_merged, fn_im[0][2])
# remove the metadata .txt file of the duplicate image
os.chmod(fn_im[1][3], 0o777)
os.remove(fn_im[1][3])
print('%d pairs of overlapping Sentinel-2 images were merged' % len(pairs))
# update the metadata dict (delete all the duplicates)
metadata_updated = copy.deepcopy(metadata)
filenames_copy = metadata_updated[sat]['filenames']
index_list = []
for i in range(len(filenames_copy)):
if filenames_copy[i].find('dup') == -1:
index_list.append(i)
for key in metadata_updated[sat].keys():
metadata_updated[sat][key] = [metadata_updated[sat][key][_] for _ in index_list]
return metadata_updated
def get_metadata(inputs):
"""
Gets the metadata from the downloaded .txt files in the \meta folders.
KV WRL 2018
Arguments:
-----------
inputs: dict
dictionnary that contains the following fields:
'sitename': str
String containig the name of the site
'filepath_data': str
Filepath to the directory where the images are downloaded
Returns:
-----------
metadata: dict
contains the information about the satellite images that were downloaded: filename,
georeferencing accuracy and image coordinate reference system
"""
# directory containing the images
filepath = os.path.join(inputs['filepath'],inputs['sitename'])
# initialize metadata dict
metadata = dict([])
# loop through the satellite missions
for satname in ['L5','L7','L8','S2']:
# if a folder has been created for the given satellite mission
if satname in os.listdir(filepath):
# update the metadata dict
metadata[satname] = {'filenames':[], 'acc_georef':[], 'epsg':[], 'dates':[]}
# directory where the metadata .txt files are stored
filepath_meta = os.path.join(filepath, satname, 'meta')
# get the list of filenames and sort it chronologically
filenames_meta = os.listdir(filepath_meta)
filenames_meta.sort()
# loop through the .txt files
for im_meta in filenames_meta:
# read them and extract the metadata info: filename, georeferencing accuracy
# epsg code and date
with open(os.path.join(filepath_meta, im_meta), 'r') as f:
filename = f.readline().split('\t')[1].replace('\n','')
acc_georef = float(f.readline().split('\t')[1].replace('\n',''))
epsg = int(f.readline().split('\t')[1].replace('\n',''))
date_str = filename[0:19]
date = pytz.utc.localize(datetime(int(date_str[:4]),int(date_str[5:7]),
int(date_str[8:10]),int(date_str[11:13]),
int(date_str[14:16]),int(date_str[17:19])))
# store the information in the metadata dict
metadata[satname]['filenames'].append(filename)
metadata[satname]['acc_georef'].append(acc_georef)
metadata[satname]['epsg'].append(epsg)
metadata[satname]['dates'].append(date)
# save a .pkl file containing the metadata dict
with open(os.path.join(filepath, inputs['sitename'] + '_metadata' + '.pkl'), 'wb') as f:
pickle.dump(metadata, f)
return metadata