标签：sel list 消息 summary 编码 details 不同 经纬度 子集
pygrib-2.0.3/docs/index.html
导入pygrib模块
>>> import pygrib
打开grib文件，获取grib消息迭代器
>>> grbs = pygrib.open(‘sampledata/flux.grb‘)
和打开正常的python文件对象一样，pygrib使用seek, tell, read, readline, 和close方法打开grib文件。唯一的不同的是，偏移量用grib消息衡量，而不是用字节。
>>> grbs.seek(2) >>> grbs.tell() 2 >>> grb = grbs.read(1)[0] # read returns a list with the next N (N=1 in this case) messages. >>> grb # printing a grib message object displays summary info 3:Maximum temperature:K (instant):regular_gg:heightAboveGround:level 2 m:fcst time 108-120 hrs:from 200402291200 >>> grbs.tell() 3
输出文件清单：
>>> grbs.seek(0) >>> for grb in grbs: >>> grb 1:Precipitation rate:kg m**-2 s**-1 (avg):regular_gg:surface:level 0:fcst time 108-120 hrs (avg):from 200402291200 2:Surface pressure:Pa (instant):regular_gg:surface:level 0:fcst time 120 hrs:from 200402291200 3:Maximum temperature:K (instant):regular_gg:heightAboveGround:level 2 m:fcst time 108-120 hrs:from 200402291200 4:Minimum temperature:K (instant):regular_gg:heightAboveGround:level 2 m:fcst time 108-120 hrs:from 200402291200
寻找匹配名字的第一个grib消息
>>> grb = grbs.select(name=‘Maximum temperature‘)[0]
使用‘values‘键提取数据值（grb.keys()将会返回一个可用键的序列）
# The data is returned as a numpy array, or if missing values or a bitmap # are present, a numpy masked array. Reduced lat/lon or gaussian grid # data is automatically expanded to a regular grid. Details of the internal # representation of the grib data (such as the scanning mode) are handled # automatically. >>> maxt = grb.values # same as grb[‘values‘] >>> maxt.shape, maxt.min(), maxt.max() (94, 192) 223.7 319.9
获取网格经纬度值
>>> lats, lons = grb.latlons() >>> lats.shape, lats.min(), lats.max(), lons.shape, lons.min(), lons.max() (94, 192) -88.5419501373 88.5419501373 0.0 358.125
获取第二个消息
>>> grb = grbs.message(2) # same as grbs.seek(1); grb=grbs.readline() >>> grb 2:Surface pressure:Pa (instant):regular_gg:surface:level 0:fcst time 120 hrs:from 200402291200
从北美洲子集中提取数据，得到经纬值
>>> data, lats, lons = grb.data(lat1=20,lat2=70,lon1=220,lon2=320) >>> data.shape, lats.min(), lats.max(), lons.min(), lons.max() (26, 53) 21.904439458 69.5216630593 221.25 318.75
使用存在的键（或者通过属性或者访问字典）修改值
>>> grb[‘forecastTime‘] = 240 >>> grb.dataDate = 20100101
得到与编码信息相关的二进制字符串
>>> msg = grb.tostring() >>> grbs.close() # close the grib file
将修改的信息写到新GRIB文件中
>>> grbout = open(‘test.grb‘,‘wb‘) >>> grbout.write(msg) >>> grbout.close() >>> pygrib.open(‘test.grb‘).readline() 1:Surface pressure:Pa (instant):regular_gg:surface:level 0:fcst time 240 hrs:from 201001011200 Documentation
标签：sel list 消息 summary 编码 details 不同 经纬度 子集
原文地址：https://www.cnblogs.com/jiangleads/p/9705787.html
