Scientific Python
Why Python & SciPy?
- Free and open source, no commercial license constraints
- Large and stable community
- Fully featured programming language, truly object oriented
- Very powerful & flexible （https://www.lfd.uci.edu/~gohlke/pythonlibs/）
- Favor readable code
- Publication quality figure ploting
- Easily read/write netcdf and grib data
- Easily work with Fortran/C/C++
- Wide library support for both numerical & non-numerical work
[from Ivan Lima’s presentation]
[from matplotlib/BaseMap example]
Read NetCDF file with scipy.io.netcdf
Scipy.io.netcdf doesn’s support writes at present and can only read NetCDF 3 files. To read a NetCDF file:
from scipy.io import netcdf
f = netcdf.netcdf_file('test.nc', 'r')
print f.history
time = f.variables['time']
print time.units
print time.shape
print time[:]
f.close()
Read/Write NetCDF file with Scientific.IO.NetCDF
To create a NetCDF file:
from Scientific.IO.NetCDF import NetCDFFile
import numpy as np
f = NetCDFFile('scientificio.nc', 'w')
# dimension
f.createDimension('time', 12)
# variable
time = f.createVariable('time', 'd', ('time',))
# data
time[:] = np.random.uniform(size=12)
f.close()
To read the file:
from Scientific.IO.NetCDF import NetCDFFile
import matplotlib.pyplot as plt
f = NetCDFFile('scientificio.nc')
fig = plt.figure()
ax = fig.add_subplot(111)
ax.plot(f.variables['time'])
plt.show()
Read/Write NetCDF file with netcdf4-python
To create a NetCDF file:
from netCDF4 import Dataset
import numpy as np
root_grp = Dataset('test.nc', 'w', format='NETCDF4')
root_grp.description = 'Example temperature data'
# dimensions
root_grp.createDimension('time', None)
root_grp.createDimension('lat', 72)
root_grp.createDimension('lon', 144)
# variables
times = root_grp.createVariable('time', 'f8', ('time',))
latitudes = root_grp.createVariable('latitude', 'f4', ('lat',))
longitudes = root_grp.createVariable('longitude', 'f4', ('lon',))
temp = root_grp.createVariable('temp', 'f4', ('time', 'lat', 'lon',))
# data
lats = np.arange(-90, 90, 2.5)
lons = np.arange(-180, 180, 2.5)
latitudes[:] = lats
longitudes[:] = lons
for i in range(5):
temp[i,:,:] = np.random.uniform(size=(len(lats), len(lons)))
# group
# my_grp = root_grp.createGroup('my_group')
root_grp.close()
To read the file:
from netCDF4 import Dataset
import pylab as pl
root_grp = Dataset('test.nc')
temp = root_grp.variables['temp']
for i in range(len(temp)):
pl.clf()
pl.contourf(temp[i])
pl.show()
raw_input('Press enter.')
Read/Write Grib files with pygrib
To read a Grib file:
import pygrib
grbs = pygrib.open('sampledata/flux.grb')
grbs.seek(2)
grbs.tell()
grb = grbs.read(1)[0]
print grb
grb = grbs.select(name='Maximum temperature')[0]
To write a Grib file:
import pygrib
grbout = open('test.grb','wb')
grbout.write(msg)
grbout.close()
print pygrib.open('test.grb').readline()
Read/Write Matlab .mat file
To read a .mat file:
import scipy.io as sio
mat_contents = sio.loadmat('data.mat')
print mat_contents
To write a .mat file:
import numpy as np
import scipy.io as sio
vect = np.arange(10)
print vect.shape
sio.savemat('data.mat', {'vect':vect})
for hdf5
f = h5py.File('foo.hdf5','w')
其他：雷达PyCINRAD
MICPAS
绘图
图形的种类
常用的
气象常用的绘图库
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image.png
