Interpolation lat lon regular grid

def create_map(ax, llcrnrlon,llcrnrlat,urcrnrlon,urcrnrlat):
     m =
 Basemap(llcrnrlon=llcrnrlon,llcrnrlat=llcrnrlat,urcrnrlon=urcrnrlon,urcrnrlat=urcrnrlat,resolution='i',projection='cyl',lon_0=(urcrnrlon+llcrnrlon)/2,lat_0=(urcrnrlat+llcrnrlat)/2)
     m.drawcoastlines()
     m.drawmapboundary()
     m.drawstates(linewidth=3)
    m.fillcontinents(color='lightgrey',lake_color='white')
     m.drawcountries(linewidth=3)
     return m


def plotMapData(ax,data):

     lats = []
     lons = []
     val = []

     for k,v in data.iteritems():
         lats.append(float(k[0]))
         lons.append(float(k[1]))
         val.append(float(v))

    value = np.array(val)
     lat = np.array(lats)
    lon = np.array(lons)

     llcrnlon = lon.min()-0.5
     llcrnlat = lat.min()-0.5
     urcrnlon = lon.max()+0.5
     urcrnlat = lat.max()+0.5

    xi = np.linspace(llcrnlon,urcrnlon,1000)
    yi = np.linspace(llcrnlat,urcrnlat,1000)
     zi = griddata(lon,lat,value,xi,yi)

    cmap = cm.jet
     m = create_map(ax,llcrnlon,llcrnlat,urcrnlon,urcrnlat)
     cs = ax.contour(xi,yi,zi,15,linewidth=0.5,cmap=cmap,alpha=0.5)
     ax.contourf(xi,yi,zi,15,cmap=cmap,zorder=1000,alpha=0.5)

     colorscale = cm.ScalarMappable()
     colorscale.set_array(value)
     colorscale.set_cmap(cmap)

     colors = colorscale.to_rgba(value)
     ax.scatter(lon,lat,c=colors,zorder=1000,cmap=cmap,s=10)
     colorbar(colorscale, shrink=0.50, ax=ax,extend='both')