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Overview

This import is available since DELFT-FEWS version 2017.01 and later.

This import type can also be used to import data using OPeNDAP, see Import data using OPeNDAP.

Parser for importing track data from a NetCDF file. This can be used for importing data that is valid according to the CF-1.6 conventions with featureType "trajectory" or "point". More information about the CF conventions can be found at http://cfconventions.org/cf-conventions/v1.6.0/cf-conventions.html.

For featureType "point" all points in the file are imported together to form a single track. For featureType "trajectory" this parser supports only a single track per file, i.e. variables in the NetCDF file must be one dimensional and only have a time dimension. For an example of the format that can be imported with this import type, see http://cfconventions.org/cf-conventions/cf-conventions.html#_single_trajectory

Track x,y coordinates are imported as normal timeSeries, i.e. they do not get any special treatment in this parser and are handled like other data variables. In fact this parser does not know about tracks at all. Tracks are constructed in other places in Delft-FEWS (e.g. trackLayer in GridDisplay) where it is possible to combine a data timeSeries with two timeSeries with x and y coordinates in the configuration to create a track.

For details about other formats of NetCDF files that can be imported in Delft-FEWS, see NetCDF formats that can be imported in Delft-FEWS.

Consequences for coordinates

The values of coordinate timeSeries are imported as normal timeSeries. Therefore for the coordinate timeSeries there must be timeSeriesSets configured in the import run and parameters configured in the id map. Furthermore the imported coordinates are rounded to floats. For global lat,lon coordinates in degrees this corresponds to a spatial accuracy of about 4 meters.

Supported properties

  • connection_retry_count (only used for importing data from an OPeNDAP server)
  • connection_retry_interval_in_milliseconds (only used for importing data from an OPeNDAP server)

Configuring the import

Note that in the idMapping, the external parameterIds must match the variable names used in the NetCDF file exactly (case sensitive). The external locationIds are not used by this import.

Example import id map config file:

<?xml version="1.0" encoding="UTF-8"?>
<idMap xmlns="http://www.wldelft.nl/fews" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.wldelft.nl/fews http://fews.wldelft.nl/schemas/version1.0/idMap.xsd" version="1.1">
    <parameter internal="latitude" external="lat"/>
    <parameter internal="longitude" external="lon"/>
    <parameter internal="H.m" external="ssha"/>
    <!-- dummy locationId (not used by track import) -->
    <location internal="H-2001" external="dummy"/>
</idMap>

Example time series import run config file:

<?xml version="1.0" encoding="UTF-8"?>
<timeSeriesImportRun xmlns="http://www.wldelft.nl/fews" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.wldelft.nl/fews http://fews.wldelft.nl/schemas/version1.0/timeSeriesImportRun.xsd">
    <import>
        <general>
            <importType>NETCDF-CF_TRAJECTORY</importType>
            <folder>../junit_test_output/nl/wldelft/fews/system/plugin/dataImport/TimeSeriesImportTestData/import/netcdf_track</folder>
            <idMapId>netcdf_track</idMapId>
        </general>
        <timeSeriesSet>
            <moduleInstanceId>NetcdfTrackImportTest</moduleInstanceId>
            <valueType>scalar</valueType>
            <parameterId>latitude</parameterId>
            <locationId>H-2001</locationId>
            <timeSeriesType>external historical</timeSeriesType>
            <timeStep unit="nonequidistant"/>
            <readWriteMode>add originals</readWriteMode>
        </timeSeriesSet>
        <timeSeriesSet>
            <moduleInstanceId>NetcdfTrackImportTest</moduleInstanceId>
            <valueType>scalar</valueType>
            <parameterId>longitude</parameterId>
            <locationId>H-2001</locationId>
            <timeSeriesType>external historical</timeSeriesType>
            <timeStep unit="nonequidistant"/>
            <readWriteMode>add originals</readWriteMode>
        </timeSeriesSet>
        <timeSeriesSet>
            <moduleInstanceId>NetcdfTrackImportTest</moduleInstanceId>
            <valueType>scalar</valueType>
            <parameterId>H.m</parameterId>
            <locationId>H-2001</locationId>
            <timeSeriesType>external historical</timeSeriesType>
            <timeStep unit="nonequidistant"/>
            <readWriteMode>add originals</readWriteMode>
        </timeSeriesSet>
    </import>
</timeSeriesImportRun>
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