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Questions tagged [opendap]

Stands for "Open-source Project for a Network Data Access Protocol"

"Open-source Project for a Network Data Access Protocol"

Home: https://www.opendap.org/
Wikipedia: https://en.wikipedia.org/wiki/OPeNDAP

44 questions
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How to select specific data variables from xarray dataset

BACKGROUND I am trying to download GFS weather data netcdf4 files via xarray & OPeNDAP. Big thanks to Vorticity0123 for their prior post, which allowed me to get the bones of the python script sorted (as below). PROBLEM Thing is, the GFS dataset has…
Bobby Heyer
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2 answers

Easy, scriptable way to sub-sample unstructured THREDDS data?

I'm trying to get a subset of data from a triangular mesh model that is being served by THREDDS. I'd like to be able to specify a LAT/LON bounding box and just get the data from within that box. The Data URL…
Steve Cousins
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4
votes
2 answers

xarray wave period in seconds ingested as timedelta64

The "units" attribute of a variable measuring ocean wave period is in "seconds". This is not a datetime field, but xarray is automatically ingesting this variable as timedelta64. Since the units are not "seconds since...", I would have assumed that…
John Maurer
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1 answer

xarray: mean of data stored via OPeNDAP

I'm using xarray's very cool pydap back-end (http://xarray.pydata.org/en/stable/io.html#opendap) to read data stored via OPenDAP at IRI: import xarray as xr remote_data =…
Ray Bell
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2
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1 answer

How to open/download MODIS data in XArray using OPeNDAP

I would like to access several MODIS products through OPeNDAP as an xarray.Dataset, for example the MOD13Q1 tiles found here. However I'm running into some problems, which I think are somehow related to the authentication. For data sources that do…
Bert Coerver
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2
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0 answers

PyDap and Xarray remote access to LP DAAC

I would like to use xarray/pydap for remote access of data on the LP DAAC OpeNDAP server. I have an earth data account (username and password - login page), and I have added the LP DAAC OpeNDAP application to my list of approved applications. Below…
Rowan_Gaffney
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Load selection GFS-ensemble openDAP data into memory (Python)

I want to download a subselection from GFS-ensemble data from an OpenDAP server via netCDF and xarray. However, when trying to load the subselection into memory, the program crashes after a while returning a RuntimeError (netCDF: I/O failure). The…
Vorticity0123
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python load OpenDap to NetcdfFile

I am opening netcdf data from an opendap server (a subset of the data) using an URL. When I open it the data is (as far as I can see) not actually loaded until the variable is requested. I would like to save the data to a file on disk, how would I…
Yorian
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2 answers

How to download nasa satellite OPeNDAP data using python

I have tried requests, pydap, urllib, and netcdf4 and keep either getting redirect errors or permission errors when trying to download the following NASA data: GLDAS_NOAH025SUBP_3H: GLDAS Noah Land Surface Model L4 3 Hourly 0.25 x 0.25 degree…
timpjohns
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2
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1 answer

How to use MFDataset to read multiple files in OPeNDAP dataset with Python NetCDF4 module?

I have an opendap thredds link to a directory holding many oceanographic model output files from the Delaware Operational Forecast System (DBOFS). Historical data are stored in separate hourly files and even some files spanning multiple hours. I'd…
Chris Englert
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1 answer

Calculating the size (bytes) of subset large netCDF file from a THREDDS Data Server before reading the file using ncvar_get?

I'm using nc_open to get a DatasetNode from a THREDDS Data Server, and reading a subset of the data in ncvar_get by specifying start and count. Reproducible example below: library(thredds) library(ncdf4) Top <-…
marine-ecologist
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1
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Matlab: Error while trying to extract data from a netCDF for a specific range

I want to read the variable “tref” for desired latitude and longitude (which I index), 24th M, 4th L, and all S from a NetCDF file: filename =…
Behzad
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1 answer

Fastest way to slice and download hundreds of NetCDF files from THREDDS/OPeNDap server

I am working with NASA-NEX-GDDP CMIP6 data. I currently have working code that individually opens and slices each file, however it takes days to download one variable for all model outputs and scenarios. My goal is to have all temperature and…
Clim Sci
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1 answer

xarray MissingDimensionsError when reading remote dataset (NBM)

When reading a remote dataset of NBM (https://vlab.ncep.noaa.gov/web/mdl/nbm) I get a xarray.core.variable.MissingDimensionsError. I'm sure i'm missing some arg settings in the open_dataset. You can see the structure of the data here:…
Ray Bell
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1
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2 answers

read in authorized opendap url using xarray

I would like to open a opendap url using xarray. It requires authorization as it held at UCAR RDA: https://rda.ucar.edu/datasets/ds084.1/#!description The url for one file is as follows…
Ray Bell
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