FossWarn: An Open-Source Solution for Multi-Platform Emergency Alerts
0:00:19 Introduction and Problem Statement: The talk introduces the issue of delayed or insufficient emergency warnings, highlighting recent events like the floods in Ahtal, Germany (2021) and severe weather in Spain. These events often result in casualties due to late or inadequate warnings, such as the absence of cell broadcasts in Germany during the 2021 floods.
0:01:26 Cell Broadcast Limitations: Cell broadcast, while effective for rapid dissemination, has limitations, including character restrictions, lack of detailed information or maps, and inability to reach devices without reception. In Germany, cell broadcast is just one component of a broader alert system comprising sirens, radio, TV, and warning apps.
0:01:55 Advantages of Cell Broadcast: This technology enables the rapid distribution of warnings to a large number of mobile devices, requiring only a compatible device logged into a cell network—no app installation or SIM card needed.
0:02:56 Issues with Existing Warning Apps: The speaker criticizes existing German warning apps (e.g., Katwarn, Nina, Hessenwarn) for their dependency on Google Play Services, limited geographic scope, and lack of cross-border functionality.
0:04:06 Proposed Solution: The presenters propose an open-source solution with an open API, free apps, integration with other systems (like OpenStreetMap), cross-border functionality, and real-time push notifications.
0:05:33 System Architecture: The proposed system consists of an aggregation server that collects warnings, standardizes their format, and allows clients to query for current alerts or subscribe to specific areas.
0:07:54 Common Alerting Protocol (CAP): The system is built on the CAP standard, a 20-year-old Oasis standard that defines an XML format for describing warning messages. CAP supports human-readable descriptions, affected area information (geographical polygons), structured data (event category, severity, urgency), and multilingualism.
0:11:19 CAP Feeds: CAP feeds, similar to RSS feeds, provide a mechanism for regularly checking for updates. The speakers have compiled a list of over 200 feeds from around 100 countries.
0:13:45 German Warning System: Germany's warning system (MoWaS) is primarily managed by the Federal Office of Civil Protection and Disaster Assistance (BBK). Other sources include the German Weather Service (DWD) and the cross-country flood portal.
0:15:38 German Weather Service (DWD): The DWD serves as a positive example with its publicly documented feeds, multilingual support, and high spatial resolution.
0:16:57 MoWaS API: MoWaS offers a JSON API, similar to CAP, which can be converted for broader use. The speakers highlight some issues with the spatial resolution and categorization of warnings in the MoWaS data.
0:20:42 Aggregation Server Details: The aggregation server is a Django application with a PostgreSQL/PostGIS database, using Celery for scheduling and supporting push notifications.
0:22:41 Fosswarn App: Fosswarn is an open-source Flutter app, available on F-Droid, designed to receive and display warnings from the aggregation server.
0:24:01 Push Notifications with UnifiedPush: The system uses UnifiedPush for push notifications, offering an open-source alternative to proprietary solutions like Google's.
0:25:41 Fosswarn App User Interface: The app allows users to select an area on a map and subscribe to warnings for that region.
0:26:15 Future Plans: Future development includes improving accessibility, adding automatic travel route registration, and creating clients for other platforms (e.g., desktop, smart home integration).
0:27:23 Call for Contributions: The speakers encourage contributions in the form of code, testing, feedback, and assistance with identifying warning infrastructure in other countries.
0:28:33 Q&A: The Q&A session addresses web interfaces, access to official warning sources, automatic subscription, filtering warnings by severity, and the possibility of modifying warning messages. The speakers clarify that they currently do not have direct access to CAP-compliant feeds from official sources like MoWaS but are working towards it. They also discuss the challenges of modifying warning messages due to potential legal and ethical issues.
0:36:06 Access Control: The CAP standard does allow for marking warnings as non-public, but this feature is rarely used and its implementation is unclear. The general principle is that warnings should be disseminated as widely as possible.