访问 netcdf 文件中嵌套组中的变量（文件格式 HDF5）
Posted
技术标签:
【中文标题】访问 netcdf 文件中嵌套组中的变量（文件格式 HDF5）【英文标题】：Access variables in nested group in netcdf file (file format HDF5) 【发布时间】：2021-05-20 22:05:48 【问题描述】：我正在尝试使用 python 和 netcdf4 库访问 NETCDF4_CLASSIC 文件中的对象“纬度”，但没有成功。当我打开文件时：
ncFile = '/path/to/file.nc4'
f = netCDF4.Dataset(ncFile, 'r')
f 我得到了这个结构：
NETCDF4_CLASSIC
<class 'netCDF4._netCDF4.Dataset'>
root group (NETCDF4_CLASSIC data model, file format HDF5):
StructMetadata_0: GROUP=SwathStructure
GROUP=SWATH_1
SwathName="2B-CLDCLASS"
GROUP=Dimension
OBJECT=Dimension_1
DimensionName="nray"
Size=37081
END_OBJECT=Dimension_1
OBJECT=Dimension_2
DimensionName="scalar"
Size=1
END_OBJECT=Dimension_2
OBJECT=Dimension_3
DimensionName="nbin"
Size=125
END_OBJECT=Dimension_3
OBJECT=Dimension_4
DimensionName="Ncloud"
Size=10
END_OBJECT=Dimension_4
END_GROUP=Dimension
GROUP=DimensionMap
END_GROUP=DimensionMap
GROUP=IndexDimensionMap
END_GROUP=IndexDimensionMap
GROUP=GeoField
OBJECT=GeoField_1
GeoFieldName="Profile_time"
DataType=DFNT_FLOAT32
DimList=("nray")
END_OBJECT=GeoField_1
OBJECT=GeoField_2
GeoFieldName="UTC_start"
DataType=DFNT_FLOAT32
DimList=("scalar")
END_OBJECT=GeoField_2
OBJECT=GeoField_3
GeoFieldName="TAI_start"
DataType=DFNT_FLOAT64
DimList=("scalar")
END_OBJECT=GeoField_3
OBJECT=GeoField_4
GeoFieldName="Latitude"
DataType=DFNT_FLOAT32
DimList=("nray")
END_OBJECT=GeoField_4
OBJECT=GeoField_5
GeoFieldName="Longitude"
DataType=DFNT_FLOAT32
DimList=("nray")
END_OBJECT=GeoField_5
OBJECT=GeoField_6
GeoFieldName="Height"
DataType=DFNT_INT16
DimList=("nray","nbin")
END_OBJECT=GeoField_6
OBJECT=GeoField_7
GeoFieldName="Range_to_intercept"
DataType=DFNT_FLOAT32
DimList=("nray")
END_OBJECT=GeoField_7
OBJECT=GeoField_8
GeoFieldName="DEM_elevation"
DataType=DFNT_INT16
DimList=("nray")
END_OBJECT=GeoField_8
OBJECT=GeoField_9
GeoFieldName="Vertical_binsize"
DataType=DFNT_FLOAT32
DimList=("scalar")
END_OBJECT=GeoField_9
OBJECT=GeoField_10
GeoFieldName="Pitch_offset"
DataType=DFNT_FLOAT32
DimList=("scalar")
END_OBJECT=GeoField_10
OBJECT=GeoField_11
GeoFieldName="Roll_offset"
DataType=DFNT_FLOAT32
DimList=("scalar")
END_OBJECT=GeoField_11
END_GROUP=GeoField
GROUP=DataField
OBJECT=DataField_1
DataFieldName="Data_quality"
DataType=DFNT_UINT8
DimList=("nray")
END_OBJECT=DataField_1
OBJECT=DataField_2
DataFieldName="Data_status"
DataType=DFNT_UINT16
DimList=("nray")
END_OBJECT=DataField_2
OBJECT=DataField_3
DataFieldName="Data_targetID"
DataType=DFNT_UINT8
DimList=("nray")
END_OBJECT=DataField_3
OBJECT=DataField_4
DataFieldName="RayStatus_validity"
DataType=DFNT_UINT8
DimList=("nray")
END_OBJECT=DataField_4
OBJECT=DataField_5
DataFieldName="Navigation_land_sea_flag"
DataType=DFNT_UINT8
DimList=("nray")
END_OBJECT=DataField_5
OBJECT=DataField_6
DataFieldName="Precip_flag"
DataType=DFNT_INT8
DimList=("nray")
END_OBJECT=DataField_6
OBJECT=DataField_7
DataFieldName="SST"
DataType=DFNT_FLOAT32
DimList=("nray")
END_OBJECT=DataField_7
OBJECT=DataField_8
DataFieldName="Surface_wind"
DataType=DFNT_FLOAT32
DimList=("nray")
END_OBJECT=DataField_8
OBJECT=DataField_9
DataFieldName="cloud_scenario"
DataType=DFNT_INT16
DimList=("nray","nbin")
CompressionType=HDFE_COMP_DEFLATE
DeflateLevel=4
END_OBJECT=DataField_9
OBJECT=DataField_10
DataFieldName="CloudLayer"
DataType=DFNT_INT16
DimList=("nray")
END_OBJECT=DataField_10
OBJECT=DataField_11
DataFieldName="CloudLayerBase"
DataType=DFNT_FLOAT32
DimList=("nray","Ncloud")
CompressionType=HDFE_COMP_DEFLATE
DeflateLevel=4
END_OBJECT=DataField_11
OBJECT=DataField_12
DataFieldName="CloudLayerTop"
DataType=DFNT_FLOAT32
DimList=("nray","Ncloud")
CompressionType=HDFE_COMP_DEFLATE
DeflateLevel=4
END_OBJECT=DataField_12
OBJECT=DataField_13
DataFieldName="CloudLayerType"
DataType=DFNT_INT16
DimList=("nray","Ncloud")
CompressionType=HDFE_COMP_DEFLATE
DeflateLevel=4
END_OBJECT=DataField_13
END_GROUP=DataField
GROUP=MergedFields
END_GROUP=MergedFields
END_GROUP=SWATH_1
END_GROUP=SwathStructure
GROUP=GridStructure
END_GROUP=GridStructure
GROUP=PointStructure
END_GROUP=PointStructure
END
HDFEOSVersion: HDFEOS_V2.5
creation_date: Wed Feb 17 03:59:37 UTC 2021
NCL_Version: 6.6.2
system: Linux 0fc9309f2c2a 4.19.112+ #1 SMP Thu Jul 23 08:00:38 PDT 2020 x86_64 x86_64 x86_64 GNU/Linux
Conventions: None
hdf_source: 2010017014344_19801_CS_2B-CLDCLASS_GRANULE_P1_R05_E03_F00.hdf
title: NCL: convert-HDF-to-netCDF
dimensions(sizes): nray_2B_CLDCLASS(37081), nbin_2B_CLDCLASS(125), Ncloud_2B_CLDCLASS(10)
variables(dimensions): int16 Height(nray_2B_CLDCLASS, nbin_2B_CLDCLASS), int16 cloud_scenario(nray_2B_CLDCLASS, nbin_2B_CLDCLASS), float32 CloudLayerBase(nray_2B_CLDCLASS, Ncloud_2B_CLDCLASS), float32 CloudLayerTop(nray_2B_CLDCLASS, Ncloud_2B_CLDCLASS), int16 CloudLayerType(nray_2B_CLDCLASS, Ncloud_2B_CLDCLASS)
groups: 我尝试了this，但没有成功。此外，当我尝试使用 f.variables.keys() 检索变量键时，我得到了
odict_keys(['Height', 'cloud_scenario', 'CloudLayerBase', 'CloudLayerTop', 'CloudLayerType'])似乎“身高”是一个变量，而“纬度”不是，即使它们在同一个 GROUP 中。我还尝试了 f.groups，输出只是 OrderedDict()。
该文件是 Cloudsat CLDCLASS.hdf 通过 NCL (convert2nc) 转换为 .nc。
任何提示将不胜感激。我是 NetCDF 世界的新手。
【问题讨论】：
【参考方案1】：dt = netCDF4.Dataset(file_names,'r')
variable = dt.groups['group_name'].variables['variable_name']
（另见https://www.codegrepper.com/code-examples/python/python+nc+group+variables）
【讨论】：
您的答案可以通过额外的支持信息得到改进。请edit 添加更多详细信息，例如引用或文档，以便其他人可以确认您的答案是正确的。你可以找到更多关于如何写好答案的信息in the help center。以上是关于访问 netcdf 文件中嵌套组中的变量（文件格式 HDF5）的主要内容，如果未能解决你的问题，请参考以下文章
使用 Java 从 HDF5 文件中的 NetCDF 字符数组变量中检索一维数组