DataType and ValueType are fields that describe how a data set was created in the Observations Data Model (ODM). For example, is the time series a daily average of field observations or laboratory samples that are done every once in a while? This information can be conveyed through these two attributes, which are controlled vocabularies in the ODM:
The DataType is field is used to categorize data sets into types that convey the frequency of observations or post-processing of the data such as creating an average or sum during a time period that is specified by the TimeSupport field. Typical entries for DataType include:
- Average: The values represent the average over a time interval, such as daily mean discharge or daily mean temperature.
- Continuous: A quantity specified at a particular instant in time measured with sufficient frequency (small spacing) to be interpreted as a continuous record of the phenomenon.
- Cumulative: The values represent the cumulative value of a variable measured or calculated up to a given instant of time, such as cumulative volume of flow or cumulative precipitation.
- Maximum: The values are the maximum values occurring at some time during a time interval, such as annual maximum discharge or a daily maximum air temperature.
- Sporadic: The phenomenon is sampled at a particular instant in time but with a frequency that is too coarse for interpreting the record as continuous. This would be the case when the spacing is significantly larger than the support and the time scale of fluctuation of the phenomenon, such as for example infrequent water quality samples.
ValueType, on the other hand, is used to convey the type of "observation" that is being made. For example, was a measurement made in the field or is it a value that comes from a model run? Typical entries for ValueType include:
- Field Observation: Observation of a variable using a field instrument.
- Derived Value: Value that is directly derived from an observation or set of observations.
- Model Simulation Result: Values generated by a simulation model.
- Sample: Observation that is the result of analyzing a sample in a laboratory.
For more information on interpreting metadata, see the Help Center article Interpreting Metadata within Search Results.