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
8 sgn=-1 #Antarctica
9 lat1,lon1,lat2,lon2,lat3,lon3,lat4,lon4=read_asar_corners(filename1)
10
11 ASAR_1=[lat1,lon1]
12 ASAR_2=[lat2,lon2]
13 ASAR_3=[lat3,lon3]
14 ASAR_4=[lat4,lon4]
15
16 ASAR_1p=mapll(ASAR_1[0],ASAR_1[1],sgn) #computing polarstereographic coordinates
17 ASAR_2p=mapll(ASAR_2[0],ASAR_2[1],sgn)
18 ASAR_3p=mapll(ASAR_3[0],ASAR_3[1],sgn)
19 ASAR_4p=mapll(ASAR_4[0],ASAR_4[1],sgn)
20
21 X=int(abs(ASAR_2p[0]-ASAR_1p[0])/resolution) #image size in pixel
22 Y=int(abs(ASAR_4p[1]-ASAR_1p[1])/resolution)
23
24 # polarstereographic coordinate system
25 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])
26 # new coordinate system with normalized coordinates
27 y10,x10,y11,x11,y12,x12,y13,x13=0,0,1,0,1,1,0,1
28
29 # calculating transformation matrix:
30 P0=array([[x00, x01, x02, x03],[y00,y01,y02,y03],[1.0,1.0,1.0,1.0]])
31 P1=array([[x10, x11, x12, x13],[y10,y11,y12,y13],[1.0,1.0,1.0,1.0]])
32
33 Faktor1=dot(P1,transpose(P0))
34 Faktor2=inverse(dot(P0,transpose(P0)))
35 A=dot(Faktor1,Faktor2) # Transformation matrix
36
37 # reading freeboard data
38 lon=[]
39 lat=[]
40 fbh=[]
41 datei = open (filename2, 'r')
42 line=datei.readline()
43 k=-1
44 while line!="":
45 k=k+1
46 data=string.split(line)
47 lon.append(float(data[0]))
48 lat.append(abs(float(data[1])))
49 fbh.append(float(data[2]))
50 line=datei.readline()
51
52 polar=mapll(array(lat),array(lon),sgn)
53
54 # calculating new coordinates for freeboard data
55 x_neu=[]
56 y_neu=[]
57 for x,y in zip(polar[0],polar[1]):
58 x_neu.append(dot(array([A[0,0],A[0,1]]),array([x,y]))+A[0,2])
59 y_neu.append(dot(array([A[1,0],A[1,1]]),array([x,y]))+A[1,2])
60
61 # cutting off non-corresponding data values
62 m=-1
63 index_vec=[]
64 for xn,yn in zip(x_neu,y_neu):
65 m=m+1
66 if xn<=1. and xn >=0. and yn<=1. and yn >=0.:
67 index_vec.append(m)
68
69 x_bild=[]
70 y_bild=[]
71 fbh_bild=[]
72 for i in index_vec:
73 x_bild.append(x_neu[i])
74 y_bild.append(y_neu[i])
75 fbh_bild.append(fbh[i])
76
77 x_y_fbh=array([x_bild,y_bild,fbh_bild])
78
79 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
8 sgn=-1 #Antarctica
9 lat1,lon1,lat2,lon2,lat3,lon3,lat4,lon4=read_asar_corners(filename1)
10
11 ASAR_1=[lat1,lon1]
12 ASAR_2=[lat2,lon2]
13 ASAR_3=[lat3,lon3]
14 ASAR_4=[lat4,lon4]
15
16 ASAR_1p=mapll(ASAR_1[0],ASAR_1[1],sgn) #computing polarstereographic coordinates
17 ASAR_2p=mapll(ASAR_2[0],ASAR_2[1],sgn)
18 ASAR_3p=mapll(ASAR_3[0],ASAR_3[1],sgn)
19 ASAR_4p=mapll(ASAR_4[0],ASAR_4[1],sgn)
20
21 X=int(abs(ASAR_2p[0]-ASAR_1p[0])/resolution) #image size in pixel
22 Y=int(abs(ASAR_4p[1]-ASAR_1p[1])/resolution)
23
24 # polarstereographic coordinate system
25 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])
26 # new coordinate system with normalized coordinates
27 y10,x10,y11,x11,y12,x12,y13,x13=0,0,1,0,1,1,0,1
28
29 # calculating transformation matrix:
30 P0=array([[x00, x01, x02, x03],[y00,y01,y02,y03],[1.0,1.0,1.0,1.0]])
31 P1=array([[x10, x11, x12, x13],[y10,y11,y12,y13],[1.0,1.0,1.0,1.0]])
32
33 Faktor1=dot(P1,transpose(P0))
34 Faktor2=inverse(dot(P0,transpose(P0)))
35 A=dot(Faktor1,Faktor2) # Transformation matrix
36
37 # reading freeboard data
38 lon=[]
39 lat=[]
40 fbh=[]
41 datei = open (filename2, 'r')
42 line=datei.readline()
43 k=-1
44 while line!="":
45 k=k+1
46 data=string.split(line)
47 lon.append(float(data[0]))
48 lat.append(abs(float(data[1])))
49 fbh.append(float(data[2]))
50 line=datei.readline()
51
52 polar=mapll(array(lat),array(lon),sgn)
53
54 # calculating new coordinates for freeboard data
55 x_neu=[]
56 y_neu=[]
57 for x,y in zip(polar[0],polar[1]):
58 x_neu.append(dot(array([A[0,0],A[0,1]]),array([x,y]))+A[0,2])
59 y_neu.append(dot(array([A[1,0],A[1,1]]),array([x,y]))+A[1,2])
60
61 # cutting off non-corresponding data values
62 m=-1
63 index_vec=[]
64 for xn,yn in zip(x_neu,y_neu):
65 m=m+1
66 if xn<=1. and xn >=0. and yn<=1. and yn >=0.:
67 index_vec.append(m)
68
69 x_bild=[]
70 y_bild=[]
71 fbh_bild=[]
72 for i in index_vec:
73 x_bild.append(x_neu[i])
74 y_bild.append(y_neu[i])
75 fbh_bild.append(fbh[i])
76
77 x_y_fbh=array([x_bild,y_bild,fbh_bild])
78
79 return x_y_fbh
80
81 filename1='ASA_IMP_1PNDPA20060617_043346_000000162048_00362_22460_2136.N1'
82 filename2='LonLatFre_1706_6.xyz'
83 resolution=0.025
84 ergebnis=fit_freeboard_ASAR(filename1,filename2,resolution)