如何使用 pygrib expand_reduce 功能？

Question

我正在使用 pygrib 打开 GFS 数据，我希望数据为非结构化格式（不是默认选项）。简而言之，如何将 expand_reduce 设置为 False？

grbs = pygrib.open(filename)
print(grbs[1].expand_reduce) # this prints True (default)

在文档 (https://jswhit.github.io/pygrib/api.html) 中说：

@ivar expand_reduced: If True (default), reduced lat/lon and gaussian grids will be expanded to regular grids when data is accessed via "values" key. If False, data is kept on unstructured reduced grid, and is returned in a 1-d array.

看了源码(https://searchcode.com/file/11567389/pygrib.pyx/)，发现是私有属性，硬编码在_create_gribmessage方法中

 625 cdef _create_gribmessage(grib_handle *gh, object messagenumber):
 626    """factory function for creating gribmessage instances"""
 627    cdef gribmessage grb  = gribmessage.__new__(gribmessage)
 628    grb.messagenumber = messagenumber
 629    grb.expand_reduced = True   ## HERE <---
 630    grb._gh = grib_handle_clone(gh)
 631    grb._all_keys = grb.keys()
 632    grb._ro_keys  = grb._read_only_keys()
 633    grb._set_projparams() # set projection parameter dict.
 634    return setdates(grb)

Answer 1

解决方法是调用expand_grid，这样会修改expand_reduced:

grbs[1].expand_grid(False)
print(grbs[1].expand_reduce) # this now prints False

如何使用 pygrib expand_reduce 功能？

how to use pygrib expand_reduce functionality?

python

gfs

pygrib