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TSTool / Datastore Reference / WaterML2

Overview

The WaterML2 input type corresponds to the WaterML 2 time series file format. WaterML is now an Open Geospacial Consortium (OGC) standard. See the following resources:

WaterML 2.0 formats are supported at various levels in the following TSTool commands: ReadUsgsNwisDaily, ReadUsgsNwisGroundwater, ReadUsgsNwisInstantaneous, ReadWaterML2, and WriteWaterML2. The WebGet command also can be used to retrieve WaterML 2 files from web services such as the USGS NWIS daily data site (see the UsgsNwisDaily Data Store appendix).

Standard Time Series Properties

This section needs to be updated for WaterML 2. The following was copied from the WaterML documentation.

The standard time series identifier for WaterML 2 time series in TSTool is of the form:

Location.DataSource.DataType.Interval~InputType~InputName

More specifically, the identifier adheres to the following convention:

SiteCode.AgencyCode.VariableCode-StatisticCode.Interval~WaterML~InputFile

where identifier parts are described as follows:

  • The SiteCode corresponds to the siteCode XML element in the sourceInfo element (e.g., this is the USGS stream gage station identifier).
  • AgencyCode corresponds to the agencyCode attribute of the siteCode XML element (e.g., USGS for USGS NWIS stream gage stations).
  • VariableCode corresponds to the variableCode XML element in the variable element (e.g., this is 00060 for streamflow for USGS stream gages). In the future, a more humanly-readable text value may be used, perhaps with a string prefix; however, such handling must guarantee that the variable is unique.
  • StatisticCode corresponds to the optionCode attribute of the option XML element in the options element, in the variable element (e.g., 00006 for USGS NWIS sum statistic). In the future, a more humanly-readable text value may be used, perhaps with a string prefix; however, such handling must guarantee that the variable is unique.
  • According to the WaterML specification, Interval should correspond to the timeScale or timeSpacing XML elements. However, current USGS NWIS WaterML does not include this information and the interval must be specified externally when reading the WaterML. A more thorough handling of the interval will be explored if full support for WaterOneFlow WaterML web services is added.
  • InputType is WaterML and InputName is the name of the WaterML file.
  • Data units correspond to the unitCode XML element in the unit element of the variable element
  • Missing numerical values are internally represented as NaN and are assigned to any date/times in the period that do not have values. The noDataValue element in the variable element is checked and matching data values are handled as missing. Often, however, missing values are simply not included as data.
  • Data value flags, if encountered, are retained in the time series. However, because the USGS uses A for approved, it may be necessary to ignore this flag so that other flags stand out more when visualized.
  • Data value qualifiers definitions are saved with time series and are available to use in time series visualization as flag definitions

Limitations

WaterML limitations relative to TSTool standard features are as follows:

  • WaterML files from NWIS do not indicate the interval of the data. Day can be assumed for the daily values web service; however, trying to read the WaterML file later requires that the interval is specified.
  • Some of the descriptions contain units, which may lead to confusion if time series are processed into different units.

TSTool Configuration File

WaterML support in TSTool is enabled/disabled using a configuration property as shown below. Note that the same property is used to enable WaterML2 as older versions.

Configuration file for TSTool

[TSTool]

WaterMLEnabled = true

TSTool Configuration File with WaterML 2 Properties