plot gps coords on german map

plot.py

import sys                                                                      
import cartopy.crs as ccrs                                                      
import cartopy.io.shapereader as shpreader                                      
import matplotlib.pyplot as plt                                                 
import json                                                                     
                                                                                
                                                                                
# Downloaded from http://biogeo.ucdavis.edu/data/gadm2/shp/DEU_adm.zip          
fname = 'DEU_adm1.shp'                                                          
                                                                                
adm1_shapes = list(shpreader.Reader(fname).geometries())                        
                                                                                
ax = plt.axes(projection=ccrs.PlateCarree())                                    
                                                                                
plt.title(sys.argv[1].split('/')[-1])                                           
ax.coastlines(resolution='10m')                                                 
                                                                                
ax.add_geometries(adm1_shapes, ccrs.PlateCarree(),                              
                  edgecolor='black', facecolor='gray', alpha=0.5)               
                                                                                
ax.set_extent([4, 16, 47, 56], ccrs.PlateCarree())                              
                                                                                
x = []                                                                          
y = []                                                                          
                                                                                
print 'Loading File...',sys.argv[1]                                             
with open(sys.argv[1]) as f:                                                    
    for i in f:                                                                 
        temp = json.loads(i)                                                    
        x.append(float(temp['x'])/10**6)                                        
        y.append(float(temp['y'])/10**6)                                        
                                                                                
plt.plot(x, y,                                                                  
         color='blue', linewidth=0, marker='.',                                 
         transform=ccrs.Geodetic(),                                             
         )                                                                      
                                                                                
plt.savefig(sys.argv[2],dpi=300)