# Designing an Interactive Visual Analytics System for
## 5 Interactive Precipitation Data Analysis System
### Station-Specific Analysis Interface  
The station-specific analysis interface allows the examination of precipitation patterns on a selected individual weather station data to find temporal trends, seasonality, and anomalies. Figure 2 shows an example of analyzing the precipitation data from a weather station located at Washington Reagan National Airport. Users can select a specific weather station and specify an IETD threshold in the control panel (A). The figure shows that a user set the IETD threshold value of 2 h and selected the period from 1950 to 2025. The map view (B) displays the geographical location of the selected station, aiding the user in understanding its physical location through navigation features (i.e., zooming and panning). Performed IETD analysis results are displayed in a data table (C) and visualized through line graphs (D). The user can perform a data search in the data table and download all the data for further evaluation. The three visualizations (D) represent hourly precipitation data. Specifically, the first visualization shows the measured hourly precipitation at a weather station. The following two visualizations represent estimated precipitation volumes--the sum of hourly precipitation (\(\mathcal{S}=\sum_{i=1}^{n}p_{i}\)) and the average hourly precipitation (\(\overline{p_{E}}^{\text{new}}=\frac{\sum_{i=1}^{n}p_{i}}{n}\)) per event. These visualizations utilize SVG (scalable vector graphics), CSS (cascading style sheets), and D3 [44] to display detailed visual and textual information. The interface also includes multiple graphical representations (E) to show quantitative analysis results. As numerous visual representations are managed, hiding each visual representation is supported for effective data analysis. Because of its multiple features, the interface supports a comprehensive understanding of precipitation patterns and their relationships across multiple analytical perspectives. Figure 2: Station -specific analysis interface with hourly precipitation data at the Washington Reagan National Airport for the period 1950–2025, using an IETD threshold of \(\theta=2\) h. The interface consists of multiple components: (**A**) station selection panel with IETD date range and threshold control, (**B**) geographical context of the selected station, (**C**) tabular IETD precipitation data, (**D**) three synchronized line graphs representing the data visually, and (**E**) eleven graphical representations showing quantitative analyses of the precipitation data. The figure demonstrates a user performing a volume-based hydrology analysis, where a specific bar within a bar graph is highlighted (see the mouse cursor). This user interaction simultaneously highlights corresponding data across all visualizations where applicable (highlighted in red). Zooming and panning user interaction techniques are added to support interactive IETD data analysis within visualizations (Figure 2D). As the visualizations are internally connected, user interactions in one visualization are seamlessly reflected and synchronized across other visualizations. With these interactions, users can navigate and explore the hourly precipitation data by initiating continuous user interactions at any point in the visualizations. For example, suppose a user zooms in to examine the detailed characteristics of the measured average IETD precipitation data. In this situation, the other two visualizations automatically adjust their visual representations by maintaining temporal alignment with the zoomed visualizations. This synchronized representation is helpful because it enables users to analyze precipitation data across different date ranges while maintaining context across other visualizations. Several statistical methods are added to support analyzing the precipitation data and presenting results through various visualizations (Figure 2E). They are designed as a comprehensive suite of statistical evaluation tools for precipitation events.