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isak/sat.py

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from PIL import Image
import requests
from sat7_pointer import *
import numpy as np
from tqdm import tqdm
from lxml import etree
# Load Landsat 7 band 1, 2, 3 TIF images and create a composite image
# from the three bands.
#
# The composite image is a greyscale image with a red, green and blue
# channel.
#
# The red channel is the red channel of band 3, the green channel is the
# green channel of band 2 and the blue channel is the blue channel of band 1.
#
# The composite image is saved as a PNG file.
band1 = Image.open("LE07_L1TP_177025_20210723_20210818_02_T1_B1.TIF")
band2 = Image.open("LE07_L1TP_177025_20210723_20210818_02_T1_B2.TIF")
band3 = Image.open("LE07_L1TP_177025_20210723_20210818_02_T1_B3.TIF")
composite = Image.merge("RGB", (band3, band2, band1))
# Load corner coordinates of the image.
#
# The coordinates are stored in a MTL text file.
mtl_data = load_metadata("LE07_L1TP_177025_20210723_20210818_02_T1_MTL.txt")
# Fetch coordinates of a city.
#
# The coordinates of a city are fetched from the OpenStreetMap API.
#
# The coordinates are used to calculate the corner coordinates of the
# composite image.
#
# # City is Belgorod, Russia.
url = "http://nominatim.openstreetmap.org/search?q=Belgorod,+Russia&format=json"
response = requests.get(url)
data = response.json()
# Convert bounding box coordinates to image coordinates.
x0, y1 = lat_lot_to_pixel(
data[0]["boundingbox"][0], data[0]["boundingbox"][2], mtl_data
)
x1, y0 = lat_lot_to_pixel(
data[0]["boundingbox"][1], data[0]["boundingbox"][3], mtl_data
)
print(x0, y0)
print(x1, y1)
print(composite.size)
# Crop the image to the bounding box coordinates.
cropped = composite.crop((x0, y0, x1, y1))
cropped.save("cropped.png")
###############################################################################
# LAB 2
###############################################################################
# Load landsat band 4 TIF image.
# Band 4 is near infrared.
band4 = Image.open("LE07_L1TP_177025_20210723_20210818_02_T1_B4.TIF")
# Claculate the NDVI.
#
# The NDVI is calculated by dividing
# difference of the red and near infrared band 4 by the sum of the
# near infrared and near infrared band 4.
#
# The NDVI is calculated for each pixel in the cropped image.
#
# The NDVI is saved as a PNG image.
ndvi = band4.copy().crop((x0, y0, x1, y1))
red = band3.copy().crop((x0, y0, x1, y1))
result = cropped.copy()
print(red.getpixel((0, 0)))
print(ndvi.getpixel((0, 0)))
# Colors for the NDVI.
def get_color(value):
if value < 0.033:
return (255, 255, 255)
elif value < 0.066:
return (196, 184, 168)
elif value < 0.1:
return (180, 150, 108)
elif value < 0.133:
return (164, 130, 76)
elif value < 0.166:
return (148, 114, 60)
elif value < 0.2:
return (124, 158, 44)
elif value < 0.25:
return (148, 182, 20)
elif value < 0.3:
return (116, 170, 4)
elif value < 0.35:
return (100, 162, 4)
elif value < 0.4:
return (84, 150, 4)
elif value < 0.45:
return (60, 134, 4)
elif value < 0.5:
return (28, 114, 4)
elif value < 0.6:
return (4, 96, 4)
elif value < 0.7:
return (4, 74, 4)
elif value < 0.8:
return (4, 56, 4)
elif value < 0.9:
return (4, 40, 4)
else:
return (0, 0, 0)
for x in tqdm(range(ndvi.size[0]), desc="NDVI"):
for y in range(ndvi.size[1]):
r = red.getpixel((x, y))
nir = ndvi.getpixel((x, y))
if nir + r == 0:
result.putpixel((x, y), get_color(0))
else:
result.putpixel((x, y), get_color((nir - r) / (nir + r)))
result.save("ndvi.png")
# Calculate FAPAR (Fraction of Absorbed Photosynthetically Active Radiation)
# for each pixel in the cropped image.
#
# Bands 1, 3, 4 are used.
solar_zenith_angle = np.radians(float(mtl_data["SUN_ELEVATION"]))
sensor_zenith_angle = np.radians(0)
sun_sensor_relative_azimuth = np.radians(float(mtl_data["SUN_AZIMUTH"]))
gain = [float(mtl_data["RADIANCE_MULT_BAND_" + str(i)]) for i in [1, 3, 4]]
offset = [float(mtl_data["RADIANCE_ADD_BAND_" + str(i)]) for i in [1, 3, 4]]
dsol = float(mtl_data["EARTH_SUN_DISTANCE"])
pic = [0.643, 0.80760, 0.89472]
k = [0.76611, 0.63931, 0.81037]
theta = [-0.10055, -0.06156, -0.03924]
k = [0.63931,0.81037, 0.76611]
pic = [0.80760, 0.89472, 0.643]
theta = [-0.06156, -0.03924, -0.10055]
E0 = [1969, 1551, 1044]
cosg = np.cos(solar_zenith_angle) * np.cos(sensor_zenith_angle) + np.sin(
solar_zenith_angle
) * np.sin(sensor_zenith_angle) * np.cos(sun_sensor_relative_azimuth)
G = (
np.tan(solar_zenith_angle) ** 2
+ np.tan(sensor_zenith_angle) ** 2
- 2
* np.tan(solar_zenith_angle)
* np.tan(sensor_zenith_angle)
* np.cos(sun_sensor_relative_azimuth)
) ** 0.5
polynoms = np.array(
[
[0.27505, 0.35511, -0.004, -0.322, 0.299, -0.0131, 0, 0, 0, 0, 0],
[-10.036, -0.019804, 0.55438, 0.14108, 12.494, 0, 0, 0, 0, 0, 1],
[
0.42720,
0.069884,
-0.33771,
0.24690,
-1.0821,
-0.30401,
-1.1024,
-1.2596,
-0.31949,
-1.4864,
0,
],
]
)
blue = band1.copy().crop((x0, y0, x1, y1))
red = band3.copy().crop((x0, y0, x1, y1))
nir = band4.copy().crop((x0, y0, x1, y1))
result = cropped.copy()
f1 = [
((np.cos(solar_zenith_angle) * np.cos(sensor_zenith_angle)) ** (k[i] - 1))
/ (np.cos(solar_zenith_angle) + np.cos(sensor_zenith_angle)) ** (1 - k[i])
for i in range(3)
]
f2 = [
(1 - theta[i] ** 2) / (1 + 2 * theta[i] * cosg + theta[i] ** 2) ** (3 / 2)
for i in range(3)
]
f3 = [1 + (1 - pic[i]) / (1 + G) for i in range(3)]
F = [f1[i] * f2[i] * f3[i] for i in range(3)]
def get_color_fapar(value, rho):
if (0 < rho[0] and rho[0] < 0.257752) \
and (0 < rho[1] and rho[1] < 0.48407) \
and (0 < rho[2] and rho[2] < 0.683928) \
and (rho[0] <= rho[2]) \
and (rho[2] >= 1.26826*rho[1]):
return get_color(value)
if (rho[0] <= 0) or (rho[1] <= 0) or (rho[2] <= 0):
return (0, 0, 0)
if (rho[0] >= 0.257752) or (rho[1] >= 0.48407) or (rho[2] >= 0.683928):
return (255, 255, 255)
if (0 < rho[0] and rho[0] < 0.257752) \
and (0 < rho[1] and rho[1] < 0.48407) \
and (0 < rho[2] and rho[2] < 0.683928) \
and (rho[0] >= rho[2]):
return (0, 0, 255)
if (0 < rho[0] and rho[0] < 0.257752) \
and (0 < rho[1] and rho[1] < 0.48407) \
and (0 < rho[2] and rho[2] < 0.683928) \
and (rho[0] <= rho[2]) \
and (1.25*rho[1] > rho[2]):
return (255, 150, 150)
if (rho[1] < 0) or (rho[2] < 0):
return (0, 0, 0)
if value < 0 or value > 1:
return (0, 0, 0)
return (int(180.0 * (1 - value)), 255, 255)
for x in tqdm(range(result.size[0]), desc="FAPAR"):
for y in range(result.size[1]):
bands = [blue.getpixel((x, y)), red.getpixel((x, y)), nir.getpixel((x, y))]
rho_i = [
(
(np.pi * (gain[i] * bands[i] + offset[i]) * dsol ** 2)
/ (E0[i] * np.cos(sensor_zenith_angle))
)
/ F[i]
for i in range(3)
]
g1 = (
(polynoms[1, 0] * (rho_i[0] + polynoms[1, 1]) ** 2)
+ (polynoms[1, 2] * (rho_i[1] + polynoms[1, 3]) ** 2)
+ polynoms[1, 4] * rho_i[0] * rho_i[1]
) / (
polynoms[1, 5] * (rho_i[0] + polynoms[1, 6]) ** 2
+ polynoms[1, 7] * (rho_i[1] + polynoms[1, 8]) ** 2
+ polynoms[1, 9] * rho_i[0] * rho_i[1]
+ polynoms[1, 10]
)
g2 = (
(polynoms[2, 0] * (rho_i[0] + polynoms[2, 1]) ** 2)
+ (polynoms[2, 2] * (rho_i[2] + polynoms[2, 3]) ** 2)
+ polynoms[2, 4] * rho_i[0] * rho_i[2]
) / (
polynoms[2, 5] * (rho_i[0] + polynoms[2, 6]) ** 2
+ polynoms[2, 7] * (rho_i[2] + polynoms[2, 8]) ** 2
+ polynoms[2, 9] * rho_i[0] * rho_i[2]
+ polynoms[2, 10]
)
FAPAR = ((polynoms[0, 0] * g2) - polynoms[0, 1] * g1 - polynoms[0, 2]) / (
(polynoms[0, 3] - g1) ** 2 + (polynoms[0, 4] - g2) ** 2 + polynoms[0, 5]
)
result.putpixel((x, y), get_color_fapar(FAPAR, rho_i))
result.save('fapar.png')
root = etree.Element("kml")
doc = etree.SubElement(root, "Document")
start_x = 550
start_y = 900
width = 30
height = 30
result = result.crop((start_x, start_y, start_x+width, start_y+height))
for x in tqdm(range(result.size[0]), desc="KML"):
for y in range(result.size[1]):
color = result.getpixel((x, y))
if color == (0, 0, 0):
continue
coord = pixel_to_lat_lot(x+x0+start_x, y+y0+start_y, mtl_data)
neighbour_r = pixel_to_lat_lot(x+1+x0+start_x, y+y0+start_y, mtl_data)
neighbour_d = pixel_to_lat_lot(x+x0+start_x, y+1+y0+start_y, mtl_data)
neighbour_rd = pixel_to_lat_lot(x+1+x0+start_x, y+1+y0+start_y, mtl_data)
placemark = etree.SubElement(doc, "Placemark")
etree.SubElement(placemark, "name").text = f"{x}_{y}"
etree.SubElement(placemark, "styleUrl").text = f"#style_{x}_{y}"
polygon = etree.SubElement(placemark, "Polygon")
outer = etree.SubElement(polygon, "outerBoundaryIs")
linearring = etree.SubElement(outer, "LinearRing")
coordinates = etree.SubElement(linearring, "coordinates")
coordinates.text = f"{coord[0]},{coord[1]},0 {neighbour_r[0]},{neighbour_r[1]},0 {neighbour_rd[0]},{neighbour_rd[1]},0 {neighbour_d[0]},{neighbour_d[1]},0 {coord[0]},{coord[1]},0"
color = result.getpixel((x, y))
color = (color[2], color[1], color[0])
color = '%02x%02x%02x' % color
color = "64" + color
style = etree.SubElement(doc, "Style")
style.set("id", f"style_{x}_{y}")
polystyle = etree.SubElement(style, "PolyStyle")
etree.SubElement(polystyle, "color").text = color
with open("fapar.kml", "wb") as f:
f.write(etree.tostring(root, pretty_print=True))
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