# Changes between Version 28 and Version 29 of udg/ecoms

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Timestamp:
Mar 14, 2013 1:44:04 PM (9 years ago)
Comment:

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 v28 The ''SPECS-EUPORIAS Data Portal'' can be accessed through the '''Data Portal URL''' provided in the abstract. First of all, an authentication dialog will request a valid user name and password. [[Image(loginTHREDDS.png,align=center,width=80%,title=Authentication dialog)]] [[Image(loginTHREDDS.png,align=center,title=Authentication dialog)]] {{{#!comment Afterwards, the different datasets described in [#s.thredds TDS section] are listed as links in the web browser window. [[Image(fig01.png,align=center,width=80%,title=Catalog of the EUPORIAS-SPECS System4 datasets. Note that although they only include a few variables, their size range from one to four Terabytes)]] [[Image(fig01.png,align=center,title=Catalog of the EUPORIAS-SPECS System4 datasets. Note that although they only include a few variables, their size range from one to four Terabytes)]] {{{#!comment By clicking in any of the datasets, a new window will appear providing information on the variables and geospatial and time coverages, and offering different options for data access and/or visualization. [[Image(fig02.png,align=center,width=80%,title=Detail of a particular dataset with information on the included variables and geospatial and time coverages. The different options for data access and visualization are also shown.)]] [[Image(fig02.png,align=center,title=Detail of a particular dataset with information on the included variables and geospatial and time coverages. The different options for data access and visualization are also shown.)]] {{{#!comment Currently, only the OPeNDAP access service is fully operative in the portal. Therefore, in this example, we will illustrate the use of this service, which allows selecting time/spatial data slices from the OPeNDAP data access form shown in Fig. \ref{fig:opendapwin} and downloading the resulting data in both ''ASCII'' and ''Binary'' formats. [[Image(openDAPwindow.png,align=center,width=80%,title=Detail of the OPeNDAP dataset access form for a particular dataset.)]] [[Image(openDAPwindow.png,align=center,title=Detail of the OPeNDAP dataset access form for a particular dataset.)]] {{{#!comment The main disadvantage of the OPeNDAP service from the end-user point of view is that the specifications for subsetting dimensions are not given in their original magnitudes (i.e., latitudes and longitudes are not given in decimal degrees), but by the indexes of their position along their respective axes (note that first index value is always 0). Thus, to find out the indexes for the desired selection, we need to dump and analyze the particular values defined in the coordinate variable. For instance, Fig.~\ref{fig:latlonDump} shows the 241 values defined for the lat (latitude) coordinate, as provided by the ''Get ASCII'' option (selecting the corresponding check-box). [[Image(latlonDump.png,align=center,width=100%,title=Text file displaying the values for the lat (latitude) coordinate variable.)]] [[Image(latlonDump.png,align=center,title=Text file displaying the values for the lat (latitude) coordinate variable.)]] {{{#!comment Using these facilities it can be obtained after some calculations that the closest lat and lon coordinates for a particular location of interest (e.g. Madrid) are 66 and 475, respectively. Thus, the time series for Madrid corresponding to the example described in the previous section (minimum temperature forecasts for January with one-month lead time, i.e. from the simulations started the first of December) could be requested as shown in Figure [[Image(opendapquery.png,align=center,width=95%,title=Detail of the query from the OPeNDAP dataset access form to retrieve a subset (a time series for a single gridbox) of minimum temperature.)]] [[Image(opendapquery.png,align=center,title=Detail of the query from the OPeNDAP dataset access form to retrieve a subset (a time series for a single gridbox) of minimum temperature.)]] {{{#!comment