= Overview of the `ecomsUDG.Raccess` package  

{{{#!td 
  * [wiki:./versions Versions]
  * [wiki:./prerequisites Pre-requisites]
  * [wiki:./authentication Authentication]
  * [wiki:./homogeneization Data Homogeneization]
  * [wiki:./examples Examples]
  * [wiki:./biascorrection Bias Correction]
}}}
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[[Image(Rlogo.jpg)]]
}}}

Since the [http://www.r-project.org/ R] language has been adopted for some key tasks in the EUPORIAS and SPECS projects (including the development of comprehensive validation and statistical-downscaling packages), the `ecomsUDG.Raccess` is envisaged as a user-friendly, R-based interface to the ECOMS User Data Gateway, enabling [http://meteo.unican.es/trac/wiki/udg/ecoms/RPackage/authentication authentication] and remote access to the different datasets (seasonal forecasting, observations, reanalysis) currently available. Moreover, `ecomsUDG.Raccess` implements data homogenization (a single vocabulary) and time filtering/aggregation functionality.

The `ecomsUDG.Raccess` package relies on the `rJava` package as an interface to the powerful capabilities of the [http://www.unidata.ucar.edu/downloads/netcdf/netcdf-java-4/index.jsp Unidata's netCDF Java library].

{{{#!comment
  * [wiki:./Functions Defined Functions]
 }}}

The following panels show an illustrative use of ECOMS-UDG to obtain the minimum DJF temperature DJF bias for System4 hindcast (one-month lead time) over Europe. WFDEI is used as reference.
||= R code =||= Output =||
{{{#!td 
   {{{#!text/R
obs <- loadECOMS(dataset = "WFDEI", 
                  var = "tasmin",
                  season = c(12,1,2))
prd <- loadECOMS(dataset = "CFSv2_seasonal", 
                  var = "tasmin", 
                  season = c(12,1,2), 
                  members = 1:2, 
                  leadMonth = 1)
  }}}
  {{{#!text/R
obsr <- interpGridData(gridData = obs, 
                  new.grid = getGrid(prd), 
                  method = "bilinear")
bias <- getBias(obsr,prd)
plotMeanField(bias, multi.member = TRUE) 
  }}}
}}}
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[[Image(fig_bias.png)]]
}}}