Die Besprechung ueber das Vorgehen ihrer Aufgaben ergab:
- die Transformation in polarstereographische Koordinaten und der nachfolgende Uebergang zu den Bildpunkten von ASAR
Eckpunkte und Aufloseung des ASAR-Bildes variieren frei -> allgemeingueltiges Programm fuer den Uebergang der Output erfolgt als Vektor in der Form x, y, Freiboardhoehe; eventuell die Floatangabe
fbh_bildkoordinaten.py
1 from polar_projection import *
2 from read_asar import *
3 import string
4
5 def fit_freeboard_ASAR(filename1,filename2,resolution):
6 """filename1: ASAR data file, filename2: freeboard data file, resolution: data resolution
7 creates new coordinate system defined by corners of ASAR image and selects freeboard values within ASAR image box
8 returns an array containing normalized image coordinates and corresponding freeboard values:
9 [x_coordinate, y_coordinate, freeboardheight(cm)]"""
10
11 sgn=-1 #Antarctica
12 lat1,lon1,lat2,lon2,lat3,lon3,lat4,lon4=read_asar_corners(filename1)
13
14 ASAR_1=[lat1,lon1]
15 ASAR_2=[lat2,lon2]
16 ASAR_3=[lat3,lon3]
17 ASAR_4=[lat4,lon4]
18
19 ASAR_1p=mapll(ASAR_1[0],ASAR_1[1],sgn) #computing polarstereographic coordinates
20 ASAR_2p=mapll(ASAR_2[0],ASAR_2[1],sgn)
21 ASAR_3p=mapll(ASAR_3[0],ASAR_3[1],sgn)
22 ASAR_4p=mapll(ASAR_4[0],ASAR_4[1],sgn)
23
24 X=int(abs(ASAR_2p[0]-ASAR_1p[0])/resolution) #image size in pixel
25 Y=int(abs(ASAR_4p[1]-ASAR_1p[1])/resolution)
26
27 # polarstereographic coordinate system
28 y00,x00,y01,x01,y02,x02,y03,x03=int(ASAR_1p[1]),int(ASAR_1p[0]),int(ASAR_4p[1]),int(ASAR_4p[0]),int(ASAR_3p[1]),int(ASAR_3p[0]),int(ASAR_2p[1]),int(ASAR_2p[0])
29 # new coordinate system with normalized coordinates
30 y10,x10,y11,x11,y12,x12,y13,x13=0,0,1,0,1,1,0,1
31
32 # calculating transformation matrix:
33 P0=array([[x00, x01, x02, x03],[y00,y01,y02,y03],[1.0,1.0,1.0,1.0]])
34 P1=array([[x10, x11, x12, x13],[y10,y11,y12,y13],[1.0,1.0,1.0,1.0]])
35
36 Faktor1=dot(P1,transpose(P0))
37 Faktor2=inverse(dot(P0,transpose(P0)))
38 A=dot(Faktor1,Faktor2) # Transformation matrix
39
40 # reading freeboard data
41 lon=[]
42 lat=[]
43 fbh=[]
44 datei = open (filename2, 'r')
45 line=datei.readline()
46 k=-1
47 while line!="":
48 k=k+1
49 data=string.split(line)
50 lon.append(float(data[0]))
51 lat.append(abs(float(data[1])))
52 fbh.append(float(data[2]))
53 line=datei.readline()
54
55 polar=mapll(array(lat),array(lon),sgn)
56
57 # calculating new coordinates for freeboard data
58 x_neu=[]
59 y_neu=[]
60 for x,y in zip(polar[0],polar[1]):
61 x_neu.append(dot(array([A[0,0],A[0,1]]),array([x,y]))+A[0,2])
62 y_neu.append(dot(array([A[1,0],A[1,1]]),array([x,y]))+A[1,2])
63
64 # cutting off non-corresponding data values
65 m=-1
66 index_vec=[]
67 for xn,yn in zip(x_neu,y_neu):
68 m=m+1
69 if xn<=1. and xn >=0. and yn<=1. and yn >=0.:
70 index_vec.append(m)
71
72 x_bild=[]
73 y_bild=[]
74 fbh_bild=[]
75 for i in index_vec:
76 x_bild.append(x_neu[i])
77 y_bild.append(y_neu[i])
78 fbh_bild.append(fbh[i])
79
80 x_y_fbh=array([x_bild,y_bild,fbh_bild])
81
82 return x_y_fbh
Die benötigten Module polar_projection.py und read_asar.py sind auf der Seite der Arbeitsgruppe 0 AG0_ASAR_Einlesen zu finden.
fbh_bildkoordinaten_test.py
1 from polar_projection import *
2 from read_asar import *
3 import string
4
5 def fit_freeboard_ASAR(filename1,filename2,resolution):
6 """filename1: ASAR data file, filename2: freeboard data file, resolution: data resolution
7 creates new coordinate system defined by corners of ASAR image and selects freeboard values within ASAR image box
8 returns an array containing normalized image coordinates and corresponding freeboard values:
9 [x_coordinate, y_coordinate, freeboardheight(cm)]"""
10
11 sgn=-1 #Antarctica
12 lat1,lon1,lat2,lon2,lat3,lon3,lat4,lon4=read_asar_corners(filename1)
13
14 ASAR_1=[lat1,lon1]
15 ASAR_2=[lat2,lon2]
16 ASAR_3=[lat3,lon3]
17 ASAR_4=[lat4,lon4]
18
19 ASAR_1p=mapll(ASAR_1[0],ASAR_1[1],sgn) #computing polarstereographic coordinates
20 ASAR_2p=mapll(ASAR_2[0],ASAR_2[1],sgn)
21 ASAR_3p=mapll(ASAR_3[0],ASAR_3[1],sgn)
22 ASAR_4p=mapll(ASAR_4[0],ASAR_4[1],sgn)
23
24 X=int(abs(ASAR_2p[0]-ASAR_1p[0])/resolution) #image size in pixel
25 Y=int(abs(ASAR_4p[1]-ASAR_1p[1])/resolution)
26
27 # polarstereographic coordinate system
28 y00,x00,y01,x01,y02,x02,y03,x03=int(ASAR_1p[1]),int(ASAR_1p[0]),int(ASAR_4p[1]),int(ASAR_4p[0]),int(ASAR_3p[1]),int(ASAR_3p[0]),int(ASAR_2p[1]),int(ASAR_2p[0])
29 # new coordinate system with normalized coordinates
30 y10,x10,y11,x11,y12,x12,y13,x13=0,0,1,0,1,1,0,1
31
32 # calculating transformation matrix:
33 P0=array([[x00, x01, x02, x03],[y00,y01,y02,y03],[1.0,1.0,1.0,1.0]])
34 P1=array([[x10, x11, x12, x13],[y10,y11,y12,y13],[1.0,1.0,1.0,1.0]])
35
36 Faktor1=dot(P1,transpose(P0))
37 Faktor2=inverse(dot(P0,transpose(P0)))
38 A=dot(Faktor1,Faktor2) # Transformation matrix
39
40 # reading freeboard data
41 lon=[]
42 lat=[]
43 fbh=[]
44 datei = open (filename2, 'r')
45 line=datei.readline()
46 k=-1
47 while line!="":
48 k=k+1
49 data=string.split(line)
50 lon.append(float(data[0]))
51 lat.append(abs(float(data[1])))
52 fbh.append(float(data[2]))
53 line=datei.readline()
54
55 polar=mapll(array(lat),array(lon),sgn)
56
57 # calculating new coordinates for freeboard data
58 x_neu=[]
59 y_neu=[]
60 for x,y in zip(polar[0],polar[1]):
61 x_neu.append(dot(array([A[0,0],A[0,1]]),array([x,y]))+A[0,2])
62 y_neu.append(dot(array([A[1,0],A[1,1]]),array([x,y]))+A[1,2])
63
64 # cutting off non-corresponding data values
65 m=-1
66 index_vec=[]
67 for xn,yn in zip(x_neu,y_neu):
68 m=m+1
69 if xn<=1. and xn >=0. and yn<=1. and yn >=0.:
70 index_vec.append(m)
71
72 x_bild=[]
73 y_bild=[]
74 fbh_bild=[]
75 for i in index_vec:
76 x_bild.append(x_neu[i])
77 y_bild.append(y_neu[i])
78 fbh_bild.append(fbh[i])
79
80 x_y_fbh=array([x_bild,y_bild,fbh_bild])
81
82 return x_y_fbh
83
84 filename1='ASA_IMP_1PNDPA20060617_043346_000000162048_00362_22460_2136.N1'
85 filename2='LonLatFre_1706_6.xyz'
86 resolution=0.025
87 ergebnis=fit_freeboard_ASAR(filename1,filename2,resolution)