unable to find variable in ncread

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akk
akk 2020-12-29
回答： Walter Roberson 2020-12-31
Hi,
Im having trouble finding variables in my nc file. First I use:
ncdisp('A20150802015171.L3b_SNSP_CHL.x.nc')
I get the display:
Source:
C:\Users\WaterLab\Downloads\requested_files\A20150802015171.L3b_SNSP_CHL.x.nc
Format:
netcdf4
Global Attributes:
product_name = 'A20150802015171.L3b_SNSP_CHL.x.nc'
title = 'MODIS Level-3 Binned Data'
instrument = 'MODIS'
platform = 'Aqua'
temporal_range = '3-month'
start_orbit_number = 68499
end_orbit_number = 69840
date_created = '2020363234255000'
processing_version = 'unspecified'
history = '/sdps/sdpsoper/Science/OCSSW/V2020.2/bin/l3bin ifile=A20150802015171.L3b_SNSP_CHL.nc ofile=A20150802015171.L3b_SNSP_CHL.x.nc latnorth=28.2000 latsouth=27.2000 lonwest=-176.2000 loneast=-175.6000'
time_coverage_start = '2015-03-21T00:05:00.000Z'
time_coverage_end = '2015-06-21T02:24:59.000Z'
northernmost_latitude = 28.1875
southernmost_latitude = 27.2292
easternmost_longitude = -175.5535
westernmost_longitude = -176.1989
geospatial_lat_max = 28.1875
geospatial_lat_min = 27.2292
geospatial_lon_max = -175.5535
geospatial_lon_min = -176.1989
geospatial_lat_units = 'degrees_north'
geospatial_lon_units = 'degrees_east'
geospatial_lon_resolution = 0.041667
geospatial_lat_resolution = 0.041667
spatialResolution = '4.6 km'
data_bins = 318
percent_data_bins = 0.0013383
units = 'chlor_a:mg m^-3,chl_ocx:mg m^-3'
binning_scheme = 'Integerized Sinusoidal Grid'
project = 'Ocean Biology Processing Group (NASA/GSFC/OBPG)'
institution = 'NASA Goddard Space Flight Center, Ocean Ecology Laboratory, Ocean Biology Processing Group'
standard_name_vocabulary = 'CF Standard Name Table v36'
Conventions = 'CF-1.6 ACDD-1.3'
naming_authority = 'gov.nasa.gsfc.sci.oceandata'
id = 'A20150802015171.L3b_SNSP_CHL.x.nc/L3/A20150802015171.L3b_SNSP_CHL.x.nc'
license = 'https://science.nasa.gov/earth-science/earth-science-data/data-information-policy/'
creator_name = 'NASA/GSFC/OBPG'
publisher_name = 'NASA/GSFC/OBPG'
creator_email = 'data@oceancolor.gsfc.nasa.gov'
publisher_email = 'data@oceancolor.gsfc.nasa.gov'
creator_url = 'https://oceandata.sci.gsfc.nasa.gov'
publisher_url = 'https://oceandata.sci.gsfc.nasa.gov'
processing_level = 'L3 Binned'
cdm_data_type = 'point'
identifier_product_doi_authority = 'https://dx.doi.org'
identifier_product_doi = '10.5067/AQUA/MODIS/L3B/CHL/2018'
keywords_vocabulary = 'NASA Global Change Master Directory (GCMD) Science Keywords'
keywords = 'Earth Science > Oceans > Ocean Chemistry > Pigments > Chlorophyll; Earth Science > Oceans > Ocean Chemistry > Chlorophyllr'
Groups:
/level-3_binned_data/
Dimensions:
binListDim = 318 (UNLIMITED)
binDataDim = 318 (UNLIMITED)
binIndexDim = 4320 (UNLIMITED)
Variables:
BinList
Size: 318x1
Dimensions: binListDim
Datatype: UNSUPPORTED DATATYPE
chlor_a
Size: 318x1
Dimensions: binDataDim
Datatype: UNSUPPORTED DATATYPE
chl_ocx
Size: 318x1
Dimensions: binDataDim
Datatype: UNSUPPORTED DATATYPE
BinIndex
Size: 4320x1
Dimensions: binIndexDim
Datatype: UNSUPPORTED DATATYPE
/processing_control/
Attributes:
software_name = 'L3BIN'
software_version = '5.13'
source = 'A20150802015171.L3b_SNSP_CHL.nc'
l2_flag_names = 'ATMFAIL,LAND,HILT,HISATZEN,STRAYLIGHT,CLDICE,COCCOLITH,LOWLW,CHLWARN,CHLFAIL,NAVWARN,MAXAERITER,ATMWARN,HISOLZEN,NAVFAIL,FILTER,HIGLINT'
Groups:
/processing_control/input_parameters/
Attributes:
infile = 'A20150802015171.L3b_SNSP_CHL.nc'
ofile = 'A20150802015171.L3b_SNSP_CHL.x.nc'
pfile = 'A20150802015171.L3b_SNSP_CHL.x.nc'
oformat = 'netCDF4'
syear = '9999'
eyear = '9999'
sday = '1970001'
eday = '2038018'
sorbit = '-1'
eorbit = '-1'
out_parm = ':DEFAULT:'
processing_version = 'unspecified'
reduce_fac = '1'
merged = ''
loneast = '-175.600006'
lonwest = '-176.199997'
latnorth = '28.200001'
latsouth = '27.200001'
verbose = '0'
unit_wgt = '0'
median = '0'
deflate = '5'
composite_prod = ''
composite_scheme = ''
I would like to open the variable chlor_a, so I type:
chla=ncread('A20150802015171.L3b_SNSP_CHL.x.nc','chlor_a')
I receive the error:
Error using internal.matlab.imagesci.nc/getGroupAndVarid (line 2096)
Could not find variable or group 'chlor_a' in file.
Error in internal.matlab.imagesci.nc/read (line 593)
[gid, varid] = getGroupAndVarid(this, location);
Error in ncread (line 66)
vardata = ncObj.read(varName, varargin{:});
I am also suprised there is not a lat and lon variable in here. Any suggestions? Thank you!
  2 个评论
Walter Roberson
Walter Roberson 2020-12-29
chla = ncread('A20150802015171.L3b_SNSP_CHL.x.nc', '/level-3_binned_data/chlor_a')
The groups are like directories

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回答（1 个）

Walter Roberson
Walter Roberson 2020-12-31
chla = ncread('A20150802015171.L3b_SNSP_CHL.x.nc', '/level-3_binned_data/chlor_a')
The groups are like directories

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