some polynoms

sat.py

@@ -1,6 +1,7 @@
 from PIL import Image
 import requests
 from sat7_pointer import *
+from numpy import np
 
 # Load Landsat 7 band 1, 2, 3 TIF images and create a composite image
 # from the three bands.
@@ -127,3 +128,33 @@ for x in range(ndvi.size[0]):
 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.
+
+# Coefficients of polynominal g_0
+# l0,1 l0,2 l0,3 l0,4 l0,5 l0,6
+# 0.27505 0.35511 −0.004 −0.322 0.299 −0.0131
+l_0 = np.array([0.27505, 0.35511, -0.004, -0.322, 0.299, -0.0131])
+
+# Coefficients of polynominal g_1
+# l1,1 l1,2 l1,3 l1,4 l1,5 l1,6 l1,7 l1,8 l1,9 l1,10 l1,11
+# −10.036 −0.019804 0.55438 0.14108 12.494 0 0 0 0 0 1.0
+l_1 = np.array([-10.036, -0.019804, 0.55438, 0.14108, 12.494, 0, 0, 0, 0, 0, 1.0])
+
+# Coefficients of polynominal g_2
+# l2,1 l2,2 l2,3 l2,4 l2,5 l2,6 l2,7 l2,8 l2,9 l2,10
+# 0.42720 0.069884 −0.33771 0.24690 −1.0821 −0.30401 −1.1024 −1.2596 −0.31949 −1.4864
+l_2 = np.array([0.42720, 0.069884, -0.33771, 0.24690, -1.0821, -0.30401, -1.1024, -1.2596, -0.31949, -1.4864])
+
+l = [l_0, l_1, l_2]
+
+# Function to calculate ratio of polynominals 
+def g_n(n, x, y):
+    if n == 0:
+        return l_0[0] * y - l_0[1] * x + l_0[2] / (l_0[3] - x)**2 + (l_0[4] - y)**2 + l_0[5]
+    if n == 1:
+        return l_1[0]
+
+    l[n][0] * (x + l[n][1])**2 + l[n][2] * (y + l[n][3])**2 + l[n][4] * x * y / l[n][5] * (x + l[n][6])**2 + l