1 from scipy import float32,int16,tan,sin,array,zeros,arange,pi,fromfile,reshape,ones,clip,log10
   2 from pylab import rc,imshow,show,gray,figure,cm,hold,colorbar,title,savefig,subplot,hist,title,close,xlabel,ylabel
   3 import scipy.ndimage as ndi
   4 import scipy.misc as misc
   5 
   6 rc('image',origin='lower',interpolation='nearest')
   7 
   8 def ql(img,vmin,vmax):
   9     figure()
  10     imshow(img,vmin=vmin,vmax=vmax)
  11     gray()
  12     show()
  13     
  14 y0,x0,wy,wx=2300,2800,1000,1000
  15 img=reshape(fromfile('ASAR_seaice_20080421_f32_5000x5000.dat',dtype=float32),(5000,5000))[y0:y0+wy,x0:x0+wx]
  16 
  17 close('all')
  18 ql(img,vmin=0,vmax=0.3)
  19 colorbar()
  20 title('Sea ice radar backscatter intensity')
  21 savefig('seaice_intensity.png',dpi=100)
  22 dbimg=10*log10(img)
  23 
  24 figure()
  25 subplot(2,1,1)
  26 hist(img,bins=500)
  27 xlabel('Intensity')
  28 ylabel('Occurrence')
  29 subplot(2,1,2)
  30 hist(dbimg,bins=500)
  31 xlabel('Intensity [dB]')
  32 ylabel('Occurrence')
  33 savefig('seaice_histogram.png',dpi=100)
  34 
  35 
  36 ql(dbimg,-30,0)
  37 colorbar()
  38 title('Sea ice radar backscatter intensity [dB]')
  39 savefig('seaice_dB.png',dpi=100)