Fast, attractive and efficient visualization in the form of time series charts is important for communicating the results of hydrologic research to the public. While there are many popular tools and application programming interfaces (API's) for creating time-series charts on the web (Google charts, HighCharts and others), none of these tools are specially tailored for hydrologic time-series observations and forecasts. This presentation introduces the concept of a free web service for generating hydrologic time-series charts from any combination of data sources available in the Consortium of Universities for Advancement of Hydrologic Science (CUAHSI)'s Hydrologic information System. This catalog of distributed services provides a growing volume of hydrological and meteorological data from many parts of the world using a standard WaterML format. By using a Representational State Transfer (REST) API, the end user can specify the time period, data source, site and variable to be displayed in the chart. Several pre-defined charts frequently used in hydrology (logarithmic plot, rainfall accumulation plot, multiple season plot, combined rainfall-runoff plot) are supported by the API. Special care has been taken for handling periods of missing data, displaying sporadic observations, and combining multiple time series in the chart. The size, quality and format of the chart can also be specified by the user. Once a chart image is generated, it can be cached on the hydrodata.info server for improving the speed of repeated requests. The hydrological time series chart API is already used in the hydrodata.cz and grafy.plaveniny.cz web portals for providing user-friendly access to hydrologic information from the Czech Republic and neighbouring countries.
Kadlec, Jiri, "Hydrodata.Info: A Web Service For Hydrological Time Series Visualization" (2014). CUNY Academic Works.