Changes between Version 4 and Version 5 of udg/interfaces


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Timestamp:
Apr 1, 2015 5:41:59 PM (7 years ago)
Author:
gutierjm
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  • udg/interfaces

    v4 v5  
    11== Web interface to explore and download data ==
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    3 The User Data Gateway (UDG) builds on a THREDDS data server which provides different web interfaces to explore and access the datasets. For instance, the NetCDF Subset Service allows to select (and download as a NetCDF file) a subset of the data (some variables in a particular region for a particular time slice). In this example, we illustrate the use of this service to select geo-temporal data subsets from the ERA-Interim (predictors for downscaling) dataset (available for VALUE and CORDEX-ESD users).
     3The User Data Gateway (UDG) builds on a THREDDS data server which provides different web interfaces to explore and access the datasets. For instance, the NetCDF Subset Service allows to select (and download as a NetCDF file) a subset of the data (some variables in a particular region for a particular time slice).
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    5 We start by clicking in the link of the corresponding  dataset
     5In this example, we illustrate the use of this service to select geo-temporal data subsets from the ERA-Interim (predictors for downscaling) dataset (available for VALUE and CORDEX-ESD users). We start by clicking in the catalog link of the corresponding  dataset:
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    7 [http://www.meteo.unican.es/tds7/ncss/interim/daily/interim20_daily.ncml/dataset.html Predictors from ERA-Interim]
     7 * Predictors from ERA-Interim [http://www.meteo.unican.es/tds7/ncss/interim/daily/interim20_daily.ncml/dataset.html (catalog)]
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    9 First of all, an authentication dialog will request a valid user name and password (see user registration for details).
     9Then resulting web page (shown in the figure below) allows selecting a number of variables (by clicking in the corresponding checkbox), geographical domain (by choosing the boundary coordinates of the spatial subset), and period (by specifying the initial and end date of the time subset). Note that the horizontal (and temporal) stride options allow selecting a sub-sampled spatial (and temporal) subsets, e.g. 3 = every third point (or time steps). Note that the 3D predictors are labelled as "VARLEVEL", where VAR is the name of the variable and LEVEL denotes the vertical coordinate (in mb); e.g. T850 refers to 850mb temperature.
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    11 The variables are stored as ''gridsets'' and, thus, auxiliary coordinate variables (lat, lon, time, member, etc.) should be handled for geo-temporal data referencing.
     11After selecting the subset of interest, the button "Submit" allows sending the request resulting in a NetCDF file. '''Note that this service is not efficient to download the whole global dataset.'''
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    13 In the following we show how to use this service to explore the structure of the datasets and to obtain simple pieces of information in ASCII format.
     13[[Image(subset.png)]]