# Designing an Interactive Visual Analytics System for
## Appendix A Creating a Composite Weather Station Dataset  
A unified station list is created to track the geographical locations of weather stations effectively. Various organizations and agencies operate and manage their weather stations and collect data, including the National Centers for Environmental Information (NCEI), NWS, FAA, the World Meteorological Organization (WMO), the International Civil Aviation Organization (ICAO), and more. Each organization uses unique identifiers to handle its stations. Thus, we created a unified station list by cross-referencing attributes from multiple data sources. Each station on the list has 46 attributes, including longitude, latitude, elevation, station name, physical address, and the dates marking the beginning and endof data collection. The list includes 85,003 stations, averaging about 1700 stations per U.S. state. Delaware has the fewest stations, numbering 181, whereas Texas has the most, with 6794 stations. The two datasets (LCD and COOP HPD) are used in this study. They use distinct station identifiers--NCDC ID for the LCD and COOP ID for the COOP HPD datasets. To combine the datasets, the Historical Observing Metadata Repository (HOMR) [99] is used as the primary weather station referencing data. HOMR is NCEI's integrated station history database. It provides detailed information for various weather stations throughout their lifespans, including identifiers, names, locations, observation times, reporting methods, photos, equipment modifications, and siting. However, HOMR does not include information on unique weather station identifiers. Therefore, we performed data filtration and merged multiple duplicate entries by cross-referencing other additional station datasets, including the primary sources of the International Civil Aviation Organization (ICAO), the FAA, Transport Canada, the NWS, and the WMO. It is important to note that this study only considers weather stations in the U.S. Thus, all international weather station identifiers are excluded. For example, Table A1 shows records about the station \"NEWPORT MUNICIPAL AP\" in Oregon, which has been operational since 1949. We found the COOP ID missing for specific periods. We also discovered that the station dataset contained duplicate entries. Thus, we reduced records by combining identical geographical information into a single station entry to address the duplicate entries and avoid missing or redundant data. Because of the scale of the data, which included numerous weather station records, we handled all inconsistently formatted data entries by evaluating the records referencing their original data specifications. As many data entries were inconsistently formatted, we performed repeated manual reviews to ensure the accuracy of the final corrected station dataset. A composite station dataset is created by incorporating multiple attributes to track each weather station. As no universal unique identifier exists to manage all weather stations, a unique identifier number is assigned to handle each station in the dataset. This number is also used to support per-station data analysis with the designed visual analytics system. As various organizations use different identifiers to handle collected weather data in weather stations, the dataset includes ten identifiers (nine IDs and one call sign) for future reference and connectivity to the original data source. For example, the NCEI uses NCDC IDs (National Climatic Data Center IDs) to manage weather station records. The World Meteorological Organization (WMO) assigns WMO station numbers to weather stations worldwide. These identifiers are used to standardize weather station data internationally.