CAP Fact Sheet
From CAP Cookbook
The Common Alerting Protocol (CAP) standardizes the content of alerts and notifications across all hazards, including law enforcement and public safety as well as natural hazards such as severe weather, fires, earthquakes, and tsunami. Systems using CAP have shown that a single authoritative and secure alert message can quickly launch Internet messages, news feeds, television text captions, highway sign messages, and synthesized voice over automated telephone calls or radio broadcasts.
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Background
The goal of public warning is to reduce the damage and loss of life caused by a natural or man-made hazard event. For efficiency and to minimize the confusion that occurs during emergencies, the alerting system should be in routine use for all hazards, including not only rare events such as earthquakes and tsunami, but for severe weather, fire, and other threats.
Emergency managers need to get timely and appropriate alerts to everyone who needs them, and to only those who need them. Authoritative alert messages should transmit on all available communications media as appropriate, including broadcast or individual targeting. Alerts can be converted automatically and securely from the CAP XML format into forms suitable for each technology: Internet, news media, television, radio, telephones, Internet, etc.
In many nations, common carriers such as radio, television, and telephone networks have implemented particular public alert technologies for hazards or threats such as weather events or civil defense. From the societal perspective of public warning investments, it makes no sense to continue building separate public warning systems for each particular threat. Efficient use of funds as well as effectiveness of public warning both argue for using standards and combining the public warning requirement for all-media coverage with the requirement for an all-hazards approach.
A standards-based, all-media, all-hazards public warning strategy not only makes sense for governments to alert the public, it makes sense for information technology providers and communications carriers as well. As these providers migrate to digital technologies, services are being offered that integrate radio and television with cellular and satellite telephone and with a variety of Internet-based and other network services. A service that supports all-hazard alerts and warnings is no longer so much a matter of designing specialized communications technology as it is a matter of simply agreeing on common standards for the content and handling of such alerts.
Benefits of CAP
CAP defines a single message format with the essential features to handle existing and emerging alert systems and sensor technologies. This standard format can replace a range of single-purpose interfaces among warning sources and disseminations channels. CAP addresses the concerns about compatibility and operational complexity that have been stifling development. CAP is a breakthrough standard that opens the door to new alerting systems and technical innovation. For example, location-aware receiving devices can use the standardized geospatial information in a CAP alert message to determine whether that particular message is relevant based on the current location of the device.
A key benefit of CAP for sending alert messages is that the sender can activate multiple warning systems with a single input. Using a single input reduces the cost and complexity of notifying many warning systems. A single input message also provides consistency in the information delivered over multiple systems. People receive exact corroboration of the warning through multiple channels. This is very important, as research has found that people do not typically act on the first warning signal but begin looking for confirmation. Only when convinced that the warning is not a false alarm, do they act on it.
CAP is designed to be compatible with all kinds of information systems and public alerting systems, including broadcast radio and television as well as public and private data networks. Rather than being defined for one particular communications technology, CAP is essentially a "content standard": a digital message format that can be applied to all types of alerts and notifications. In this way, CAP is compatible with emerging technologies such as Internet Web services, and with existing formats such as the U.S. national Emergency Alert System and the Specific Area Message Encoding (SAME) used for NOAA Weather Radio in the U.S. CAP is also compatible with alerting systems designed for multilingual and special-needs populations. By reducing the barriers of technical incompatibility, CAP creates the foundation for a technology-independent national and international "warning internet".
A further benefit of CAP for emergency managers is that standardized warnings from various sources can be compiled in tabular or graphical form as an aid to situational awareness and pattern detection. When CAP is applied extensively, managers will be able to monitor at any one time the whole picture of local, regional, and national warnings of all types. CAP alert messages can also be used at sensor systems as a format for direct reporting of relevant events to centers for collection and analysis.
The CAP Message Format
The CAP message format uses the eXtensible Markup Language (XML) to implement the recommendation of the National Science and Technology Council's report on "Effective Disaster Warnings" (2000) that:
"A standard method should be developed to collect and relay instantaneously and automatically all types of hazard warnings and reports locally, regionally and nationally for input into a wide variety of dissemination systems."
The CAP XML format was reviewed and refined in consultation with emergency managers and public safety professionals and adopted as a standard by the international Organization for the Advancement of Structured Information Standards (OASIS) in April, 2004.
The CAP format is designed to contain a broad range of information about the alert message, the specific hazard event, and appropriate responses. Effective warning systems need to reach everyone who is at risk, wherever they are and whenever the event occurs, yet must not alarm people unnecessarily. Systems must be easy to use, reliable and secure. An effective warning message delivered by such a system must be accurate, specific, and action oriented. And, warning messages must be understandable in terms of languages and special needs, with attention to the prior knowledge and experience of the receivers. It is also critical that times, places, and instructions are easily understood.
Each CAP message includes information that describes the message itself. Messages have unique identification numbers, and may reference other, related CAP messages. Identifying information about the message also includes the status and time sent, allowing messages to serve as updates and cancellations of previous messages. In addition, messages are identified by source, and are compatible with digital encryption and signature techniques that ensure the reliability and security of the message.
The information about an event in a CAP message may be contained in multiple informational segments. Each informational segment includes a description of the event in terms its urgency, severity, and certainty. CAP has separate descriptions for each of these three characteristics. Urgency describes how much time is available to prepare; Severity describes the intensity of the impact; and Certainty is a measure of confidence in the observation or prediction being made. The event may be assigned to a category (e.g., geophysical, meteorological, safety, security, rescue, fire, health, environmental, transportation, infrastructure), and is also described in text. CAP also supports the inclusion of associated digital images and audio. The inclusion of audio messages, for example, allows warnings to be broadcast directly on radio, without requiring an announcer to read the message text aloud.
Multiple informational segments allow the message to be transmitted in multiple languages or to multiple audiences. Because each segment is associated with a geographic description, the multiple segments may also be used to convey information about bands of intensity. For example, an industrial fire might develop the potential for a major explosion. The incident commander needs to specify several components: evacuation of the area within half a mile of the fire; shelter-in-place instruction for the dispersion plume; and a request for media and aircraft to remain above 2500 feet in the vicinity of the fire. Using CAP, the incident commander can send one message including the appropriate message elements for each area. The incident commander supplies the geographic descriptions, expressed using latitude, longitude, and altitude, by outlining a polygon on a displayed map as he enters the CAP message.
Current Deployment of CAP
The OASIS Common Alerting Protocol is the agreed international standard for all-hazard alert messages. All-media distribution of CAP messages is being implemented on ever larger scales, types of alerts, and ranges of technologies.
The United States Department of Homeland Security is conducting trials in and around the Washington, D.C., area using CAP over digital television and satellite broadcasts to provide an enhanced version of the existing EAS broadcast alerting system.
The Office of Management and Budget has enjoined all Federal agencies to implement CAP. The U.S. Geological Survey is leading in CAP implementation for the Department of the Interior. Earthquake notifications in CAP format will be available from USGS by the end of June, 2005. CAP messages for landslides and volcanoes will be available by the end of September, 2005. These CAP messages will also be disseminated through a communications link to NOAA's HazCollect system. This allows distribution through NOAA All-hazards Radio and the Emergency Alert System (EAS) in cooperation with the Department of Homeland Security.
The California Office of Emergency Services is converting its existing Emergency Digital Information Service to more fully utilize the advanced targeting and more complete information model provided by CAP.
Applications using CAP have been deployed in multi-vendor events and field trials in Washington, D.C., Virginia, Florida, Nevada and California. Implementors of CAP already include: U.S. Department of Homeland Security; U.S. National Weather Service; California Office of Emergency Services; Virginia Department of Transportation; Capital Wireless Integrated Network (CapWIN); GeoDecisions, Inc.; E Team; Blue292; Warning Systems, Inc.; Comlabs, Inc.; mobileFoundations; Ship Analytics; MyStateUSA; Integrated Environmental Management, Inc.; Hormann America, Inc.; Oregon RAINS; and NDS, Ltd.; among others.
