Vectors being plotted outside the desired limit

[KhanalKrishna]

import matplotlib.pyplot as plt
import pydarn
from datetime import datetime
import matplotlib

map_file = "20110128.north.map2"
map_data = pydarn.SuperDARNRead().read_dmap(map_file)
stime= datetime(2011, 1, 28, 18)

lats,lons,data = pydarn.Maps.plot_mapdata(map_data, start_time=stime, parameter=pydarn.MapParams.FITTED_VELOCITY,
lowlat=75, colorbar_label='Velocity m/s',
contour_fill = False,
contour_fill_cmap= 'RdBu',
contour_colorbar = False,
contour_colorbar_label='Potential (kV)',
pot_minmax_color = 'r',
map_info=True, imf_dial=True, hmb=False,cmap=matplotlib.cm.jet)
plt.show()