2017-09-26 269 views
2

我知道如何手动将netCDF4.Dataset转换为xarray DataArray。不过,我想知道是否有简单而优雅的方式,例如使用xarray后端,以下“netCDF4.Dataset”对象的简单转换为xarray于DataArray对象:netCDF4.Dataset简单转换为xarray数据集

<type 'netCDF4.Dataset'> 
root group (NETCDF4 data model, file format HDF5): 
    Originating_or_generating_Center: US National Weather Service, National Centres for Environmental Prediction (NCEP) 
    Originating_or_generating_Subcenter: NCEP Ensemble Products 
    GRIB_table_version: 2,1 
    Type_of_generating_process: Ensemble forecast 
    Analysis_or_forecast_generating_process_identifier_defined_by_originating_centre: Global Ensemble Forecast System (GEFS) 
    Conventions: CF-1.6 
    history: Read using CDM IOSP GribCollection v3 
    featureType: GRID 
    History: Translated to CF-1.0 Conventions by Netcdf-Java CDM (CFGridWriter2) 
Original Dataset = /data/ldm/pub/native/grid/NCEP/GEFS/Global_1p0deg_Ensemble/member/GEFS_Global_1p0deg_Ensemble_20170926_0600.grib2.ncx3#LatLon_181X360-p5S-180p0E; Translation Date = 2017-09-26T17:50:23.259Z 
    geospatial_lat_min: 0.0 
    geospatial_lat_max: 90.0 
    geospatial_lon_min: 0.0 
    geospatial_lon_max: 359.0 
    dimensions(sizes): time2(2), ens(21), isobaric1(12), lat(91), lon(360) 
    variables(dimensions): float32 u-component_of_wind_isobaric_ens(time2,ens,isobaric1,lat,lon), float64 time2(time2), int32 ens(ens), float32 isobaric1(isobaric1), float32 lat(lat), float32 lon(lon), float32 v-component_of_wind_isobaric_ens(time2,ens,isobaric1,lat,lon) 
    groups: 

我有了这个使用siphon.ncss

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是一个更好的标题为您的问题:“简单的netCDF4.Dataset转换为xarray.Dataset”?如果是这样,@DopplerShift有正确的答案。 – jhamman

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由于netCDF4.Dataset可以包含多个变量,因此无法将其转换为DataArray ... – DopplerShift

回答

4

xarray的下一个版本(0.10)有支持这事,或者至少得到一个xarray 数据集从netCDF4之一,正是原因你要使用它:

import xarray as xr 

nc = nc4.Dataset('filename.nc', mode='r') # Or from siphon.ncss 
dataset = xr.open_dataset(xr.backends.NetCDF4DataStore(nc)) 

或者与siphon.ncss,这看起来像:

from datetime import datetime 
from siphon.catalog import TDSCatalog 
import xarray as xr 

gfs_cat = TDSCatalog('http://thredds.ucar.edu/thredds/catalog' 
        '/grib/NCEP/GFS/Global_0p5deg/catalog.xml') 
latest = gfs_cat.latest 
ncss = latest.subset() 
query = ncss.query().variables('Temperature_isobaric') 
query.time(datetime.utcnow()).accept('netCDF4') 
nc = ncss.get_data(query) 
dataset = xr.open_dataset(xr.backends.NetCDF4DataStore(nc)) 

,直到它的发布,你可以从主安装xarray。否则,唯一的其他解决方案是手动完成所有工作。

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是的,当我使用xarray'0.9.6'和上面的代码时,我收到** TypeError **: '预期的字符串或Unicode对象,找到netCDF4.Dataset'。但是,当我使用xarray'0.9.6-51-g25d1855'时,在'siphon.ncss中调用了数据集(tmp_file.name,'r')'时,我收到** RuntimeError **:'NetCDF:HDF error' '。你能重现吗? – Ales

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我更新了答案,以明确显示如何使用'siphon.ncss'。 – DopplerShift

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链接到笔记本电脑不适合我。 – DopplerShift