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DONAR MWL time series data in OpenEarth:

  1. Raw data + scripts (ascii + Matlab)
    • All ascii time series data are available via a live web service from Rijkswaterstaat called Waterbase. The Waterbase web site has a menu to guide you to the correct data which are available via a direct access download mechanism: http://live.waterbase.nl.
    • The ascii files that are returned by Waterbase need to be parsed. OpenEarthTools has a function to parse these files into a matlab struct: rws_waterbase_load.m. We recommend to choose the text files from Waterbase, and not the Excel files. The Excel files are not real (binary) Excel files, but are tab-delimeted ascii files. This means that they do load well into excel, but also that you cannot read them into Matlab with xlsread.
    • The waterbase menu is in fact only a macro to construct a url that is called to download the data. Passing command to a server via a url is a so-called web service. The web service urls to download the data can also be constructed without the macro, and be called directly from other programs, for instance Matlab. The syntax for the waterbase urls is fairly simple. For instance, to download the water levels from Katijk in in the 18th century you can use this url. This url consists of a base-url followed by ampersand(&)-separated keywords. 
      http://live.waterbase.nl/wboutput.cfm?
loc=KATWK
&wbwns=1|Waterhoogte+in+cm+t.o.v.+normaal+amsterdams+peil+in+oppervlaktewater
&byear=1737&bmonth=01&bday=01
&eyear=1808&emonth=01&eday=01
&output=Tekst
&whichform=2
      The method to pass command via url keywords is the typical for web services, and has the same syntax-grammer same as the international WMS and WCS standards used for grids. For time series there is no internationally accepted set f keywords yet, although the WFS standard seems to fit. Ampersand separated keywords are also is also used in the operational Matroos system of Rijkswaterstaat.
    • In OpenEarthTools we made a toolbox that constructs the Waterbase urls for specific combinations of parameter and location. The toolbox allows you to download the data from within Matlab. These tools have prefix rws_waterbase_get*.m.
      Toolbox for downloading and parsing:
      https://svn.oss.deltares.nl/repos/openearthtools/trunk/matlab/applications/Rijkswaterstaat/.
  2. Standardized data (netCDF on OPeNDAP)
    • Working with a bunch of text files as returned is not very useful. For every program dedicated parse functions have to be programmed. Therefore we programmed a matlab workflow that downdload Waterbase data automatically using the aboe mentioned web service urls, parses them into Matlab memory with rws_waterbase_load.m, and uses rws_waterbase2nc.m to save them as a netCDF file obeying the upcoming CF conventions time series, and adding UM Aquo meta-data. These netCDF files are made available on our OPeNDAP server. As a last step we make an overview of all stations for one parameter in a kml file. One matlab script rws_waterbase_all.m performs this entire workflow.
      Toolbox for downloading, parsing and transformation to netCDF+kml:
      https://svn.oss.deltares.nl/repos/openearthtools/trunk/matlab/applications/Rijkswaterstaat/.
    • netCDF data: http://opendap.deltares.nl/thredds/catalog/opendap/rijkswaterstaat/waterbase/catalog.html
  3. Visualized data overviews with previews of statistics (kml)

DONAR MWTL time series (waterbase) description:

See also:

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