content: __author__ = 'sonal'
  
  import numpy as np
  from mpl_toolkits.basemap import Basemap
  import matplotlib.pyplot as plt
  from matplotlib import cm
  from mpl_toolkits.axes_grid1 import make_axes_locatable
  import os
  from math import *
  
  def polar_plot(grid, title):
  
      #z = grid[:,8]
      u = grid[:,8]
      v = grid[:,9]
      plt.figure(figsize=(18,18))
      ax = plt.gca()
      #m = Basemap(projection='npaeqd',boundinglat=20,lon_0=-100.,resolution='l')
      m = Basemap(width=8000000, height=8000000, resolution='l', projection='lcc',\
               lat_0=60,lon_0=-100.)
      m.drawcoastlines()
      m.drawparallels(np.arange(-80.,81,20.),labels=[1,0,0,0],fontsize=10)
      m.drawmeridians(np.arange(-180.,181.,20.),labels=[0,0,0,1],fontsize=10)
  
      x,y =m(grid[:,7],grid[:,6])
      sc = m.scatter(x,y,s=abs(u),c=u,marker=',',cmap=cm.jet,alpha=0.9,edgecolors='none')
      plt.title(title)
  
      divider = make_axes_locatable(ax)
      cax = divider.append_axes("right", size="5%", pad=0.05)
      cb1 = plt.colorbar(sc,cax=cax)
      cb1.set_label("mA/m",fontsize=18)
      plt.savefig('GOCE_asc_EICSu_krigged_201104.png',bbox_inches='tight',pad_inches=0.2)
      #plt.show()
  
  def asc_desc(data):
      asc = []
      desc = []
      lat = data[:,6]
      for i in range(0,len(data)-1):
          if lat[i+1] >= lat[i]:
              asc.append(i)
          else:
              desc.append(i)
  
      return asc, desc
  
  SECS_data = np.loadtxt('EICS_201103_krigged.txt')
  
  asc_idx, desc_idx= asc_desc(SECS_data)
  
  asc_track = SECS_data[asc_idx,:]
  desc_track = SECS_data[desc_idx,:]
  
  
  polar_plot(asc_track,'GOCE Ascending EICS u component Krigged April, 2011')