NovaStar Data / Ratings
Introduction
A "rating" in water resources typically refers to the conversion of a water level to a discharge value. This can occur by applying one or more equations to the input value (depending on where the input falls in a range), or by using a lookup rating table to interpolate input to output.
NovaStar supports the above approach but also uses ratings for other conversions.
Ratings in NovaStar
Ratings in NovaStar are used to convert the scaled point value into a "rated" value, which is a derived value. Unlike calibrations, ratings can be fairly complex. The term "ratings" applies to traditional use such as rating table that converts river stage (water level) to discharge and to other standard calculations that don't involve a rating table. Examples of ratings include:
- using a rating table to convert an input value to an output value (e.g., a lookup table with interpolation)
- computing incremental precipitation from accumulated precipitation
- computing storm and seasonal precipitation totals
Data web services allow rated values to be queried and such time series are called "rated value" time series. Rating assignments use an effective time because characteristics of ratings can change over time.
Services
The following services are related to ratings:
- ratingAssigns - return relationships between ratings and points
- ratingTables - return rating tables (can be shared among multiple points)
- ratingRows - return rating rows for rating table or lists of rating equations
- ratingShifts - return shifts that adjust a previously measured rating for conditions that have changed (e.g., erosion or sedimentation)