Import Module Configuration

The import module allows data from external source to be imported into DELFT-FEWS. Data may be provided to FEWS in a variety of formats. The approach taken in the import module is that a class is defined for each of the file formats that can be imported.

Data is imported from specified directories. An attempt is made to import all files in the directories configured. If a file conforms to the expected format then the data will be imported. If the file does not conform to the expected format, it will not be imported, but will be moved to a configurable directory with failed import files.

Two main groups of import can be defined;

• Importing data in the XML format defined by the Environment Agency, UK.
• Importing of various data formats (including ASCII formats, png files- e.g. meteosat images- grids and GRIB files).

On importing data, the approach to be used for converting flags, units, locations and parameters can be defined. These conversions are identified by referring to the appropriate configuration files (see Regional Configuration). When data is imported to an equidistant time series, a time tolerance may also be defined. If the time recorded is within this tolerance it will be snapped to the cardinal time step in the imported series.

When available as configuration on the file system, the name of the XML file for configuring an instance of the import module called for example ImportRTS may be:

ImportRTS 1.00 default.xml

ImportRTS File name for the ImportRTS configuration.
1.00 Version number
default Flag to indicate the version is the default configuration (otherwise omitted).

Time Series Import Module

The time series import class can be applied to import data from a variety of external formats. The formats are included in an enumeration of supported import types. Each of these enumerations is used for a specifically formatted file.

Figure 62 Elements of the TimeSeriesImport configuration

import

Root element for the definition of an import run task. Each task defined will import data in a specified format from a specified directory. For defining multiple formats, different import tasks reading from different directories must be defined.

general

Root element for general definitions used in the import runs.

description

Optional description for the import run. Used for reference purposes only.

importType

Specification of the format of the data to be imported. The enumeration of options includes;

• MSW : Import of data provided by the MSW System (Rijkswaterstaat, the Netherlands).
• KNMI : Import of synoptic data from KNMI (Dutch Meteorological Service).
• WISKI : Import of time series data from the WISKI Database system (Kisters AG).
• DWD-GME : Import of NWP data of the DWD Global Modell, (German Meteorological Service). This is a grid data format.
• DWD-LM : Import of NWP data of the DWD Lokal Modell, (German Meteorological Service). This is a grid data format.
• GRIB : Import of the GRIB data format. General format for exchange of meteorological data.
• EVN: Import of data in the EVN format (Austrian Telemetry)
• METEOSAT: Import of images form meteosat satellite

folder

Folder to import data from. This may be a UNC path (ie located on the network).

failedFolder

Folder to move badly formatted files to. This may be a UNC path (ie located on the network).

idMapId

ID of the IdMap used to convert external parameterId's and locationId's to internal parameter and location Id's. Each of the formats specified will have a unique method of identifying the id in the external format. See section on configuration for Mapping Id's units and flags.

unitConversionsId

ID of the UnitConversions used to convert external units to internal units. Each of the formats specified will have a unique method of identifying the unit in the external format. See section on configuration for Mapping Id's units and flags.

flagConversionsId

ID of the FlagConversions used to convert external data quality flags to internal data quality flags. Each of the formats specified will have a unique method of identifying the flag in the external format. See section on configuration for Mapping Id's units and flags.

missingValue

Optional specification of missing value identifier in external data format.

importTimeZone

Time zone the external data is provided in if this is not specified in the data format itself. This may be specified as a timeZoneOffset, or as a specific timeZoneName.

timeZoneOffset

The offset of the time zone with reference to UTC (equivalent to GMT). Entries should define the number of hours (or fraction of hours) offset. (e.g. +01:00)

timeZoneName

Enumeration of supported time zones. See appendix B for list of supported time zones.

gridStartPoint

Identification of the cell considered as the first cell of the grid. This may be in the upper left corner or in the lower left corner. Enumeration of options include;

• NW : for upper left
• SW : for lower left
  

  tolerance

  Definition of the tolerance for importing time values to cardinal time steps in the series to be imported to. Tolerance is defined per location/parameter combination. Multiple entries may exist.

Attributes;

• locationId : Id of the location tolerance is to be considered for.
• parameterId : Id for the parameter tolerance is to be considered for.
• timeUnit : Spefication of time units tolerances is defined in (enumeration).
• unitCount : integer number of units defined for tolerance.
  

  startTimeShift

  Specification of a shift to apply to the start time of a data series to be imported as external forecasting. This is required when the time value of the first data point is not the same as the start time of the forecast. This may be the case in for example external precipitation values, where the first value given is the accumulative precipitation for the first time step. The start time of the forecast is then one time unit earlier than the first data point in the series. Multiple entries may exist.
  

  startTimeShift:locationId

  Id of the location to apply the startTimeShift to.
  

  startTimeShift:parameterId

  Id of the parameter to apply the startTimeShift to.
  

  timeSeriesSet

  TimeSeriesSet to import the data to. Multiple time series sets may be defined, and each may include either a (list of) locationId's ar a locationSetId. Data imported is first read from the source data file in the format specifed. An attempt is then made to map the locationId's and the parameterId's as specified in the IdMap's to one of the locations/parameters defined in the import time series sets. If a valid match is found, then the time values are mapped to those in the timeSeriesSet, taking into account the tolerance for time values. A new entry is made in the timeSeries for each valid match made.

For non-equidistant time series the time values imported will be taken as is. For equidistant time series values are only returned on the cardinal time steps. For cardinal time steps where no value is available, no data is returned.

externUnit

For some data formats an external unit is not defined in the file to be imported. This elements allows the unit to be specified explicitly. This unit is then used in possible unit conversions.

Attributes;

• parameterId: Id of the parameter for which a unit is specified. This is the internal parameter Id.
• unit: specification of unit. This unit must be available in the UnitConversions specified in the unitConversionsId element.
  

  gridRecordTimeIgnore

  Boolean flag to specify if the start of forecast is read from the GRIB file or if it is inferred from the data imported. In some GRIB files a start of forecast is specified, but the definition of this may differ from that used in DELFT-FEWS.

Example: Import of Meteosat images as time-series

Meteosat Images are generally imported as images in _\[filename\].png_ format. The Meteosat images constitute a time series of png images, that are geo-referenced by means of a specific world file. Each image needs its own world file, which in case of PNG carries the extension _\[filename\].pgw_ . 
Import of images in another format, such as JPEG is also possible. The corresponding world file for a JPEG file has the extension _\[filename\].jpg_ .
The images are imported via a common time series import, for which a specific image parameter needs to be specified in a _parameterGroup_ via the parameter id _image_ .

_\[parameterGroup id="image"\]_ 
_		  \[parameterType\]instantaneous\[/parameterType\]_ 
_		  \[unit\]-\[/unit\]_ 
_		  \[valueResolution\]8\[/valueResolution\]_ 
_		  \[parameter id="image"\]_ 
_		   \[shortName\]image\[/shortName\]_ 
_		  \[/parameter\]_ 
_\[/parameterGroup\]_ 

The value resolution indicates the resolution of the values of the pixels (grey tones) in the Meteosat images. In this case 8 grey tones are resampled into a single grey tone for storage space reductions. In the module for the timemeseries import run for a Meteosat image the import is then configured as follows:

_\[import\]_ 
_  \[general\]_ 
_   \[importType\]GrayScaleImage\[/importType\]_ 
_   \[folder\]$REGION_HOME$/Import/MeteoSat\[/folder\]_ 
_            \[idMapId\]IdImportMeteosat\[/idMapId\]_ 
_   \[/general\]_ 
__ 
_  \[timeSeriesSet\]_ 
_   \[moduleInstanceId\]ImportMeteosat\[/moduleInstanceId\]_ 
_   \[valueType\]grid\[/valueType\]_ 
_   \[parameterId\]image\[/parameterId\]_ 
_   \[locationId\]meteosat\[/locationId\]_ 
_   \[timeSeriesType\]external historical\[/timeSeriesType\]_ 
_   \[timeStep unit="minute" multiplier="15"/\]_ 
_   \[readWriteMode\]add originals\[/readWriteMode\]_ 
_   \[synchLevel\]4\[/synchLevel\]_ 
_   \[expiryTime unit="day" multiplier="750"/\]_ 
_  \[/timeSeriesSet\]_ 
_ \[/import\]_ 

• • The goereferenced image can then be displayed in the grid display.
    

    EA Import module

    A specific import class is available for importing time series data from the XML format specified by the UK Environment Agency. The configuration items required are a sub-set of those required in the more generic time series import format. This is due to much of the required information being available in the XML file itself (ie file is self describing).

Figure 63 Elements of the EAImport configuration.