python地理 Python教程地理視覺化

matplotlib是python常用的資料繪製包，其繪圖功能強大；而basemap則是matplotlib的乙個子包，負責地圖繪製。本文簡單介紹如何利用該程式包繪製風向圖。具體操作如下：

匯入命令

1)設定工作環境並匯入程式包%cd "f:\\dropbox\\python"

import numpy as np

import matplotlib.pyplot as plt

import datetime

from mpl_toolkits.basemap import basemap, shiftgrid

from netcdf4 import dataset

3)設定時間並讀取資料yyyy=1993; mm=03; dd=14; hh=00

date = datetime.datetime(yyyy,mm,dd,hh)

urlbase=""

url=urlbase+"%04i/%04i%02i/%04i%02i%02i/pgbh00.gdas.%04i%02i%02i%02i.grb2" %\

(yyyy,yyyy,mm,yyyy,mm,dd,yyyy,mm,dd,hh)

data = dataset(url)

4)資料預處理latitudes = data.variables['lat'][::-1]

longitudes = data.variables['lon'][:].tolist()

slpin = 0.01*data.variables['pressure_msl'][:].squeeze()

slp[:,0:-1] = slpin[::-1]; slp[:,-1] = slpin[::-1,0]u = np.zeros((uin.shape[0],uin.shape[1]+1),np.float64)

u[:,0:-1] = uin[::-1]; u[:,-1] = uin[::-1,0]v = np.zeros((vin.shape[0],vin.shape[1]+1),np.float64)v[:,0:-1] = vin[::-1];

5)設定並繪製圖示m = basemap(resolution='c',projection='ortho',lat_0=60.,lon_0=-60.)fig1 = plt.figure(figsize=(8,10))

ax = fig1.add_axes([0.1,0.1,0.8,0.8])clevs = np.arange(960,1061,5)x, y = m(lons, lats)parallels = np.arange(-80.,90,20.)

meridians = np.arange(0.,360.,20.)cs1 = m.contour(x,y,slp,clevs,linewidths=0.5,colors='k',animated=true)

cs2 = m.contourf(x,y,slp,clevs,cmap=plt.cm.rdbu_r,animated=true)ugrid,newlons = shiftgrid(180.,u,longitudes,start=false)

vgrid,newlons = shiftgrid(180.,v,longitudes,start=false)

uproj,vproj,xx,yy = \

m.transform_vector(ugrid,vgrid,newlons,latitudes,31,31,returnxy=true,masked=true)

q = m.quiver(xx,yy,uproj,vproj,scale=700)qk = plt.quiverkey(q, 0.1, 0.1, 20, '20 m/s', labelpos='w')m.drawcoastlines(linewidth=1.5)

m.drawparallels(parallels)

m.drawmeridians(meridians)

cb = m.colorbar(cs2,"bottom", size="5%", pad="2%")

cb.set_label('hpa')

ax.set_title('slp and wind vectors '+str(date))

plt.show()

輸出影象如下

python地理 Python教程 地理視覺化