Moving Area Blocks How do moving area blocks work with Preset Polygons Alert Message Polygons Subject event Polygons

Preset polygons translate to geocodes in a CAP file that then make heavy use of lookup tables (common in non-GIS CAP based systems)

Preset polygons change to reflect the new time period by adding or deleting new polygons to the list of affected polygons

Alert message polygons define the area to be alerted (used when mapping to broadcast assets within the affected area)

Alert message polygons change to reflect the new area to be alerted (used when mapping to broadcast assets within the affected area)

Subject event polygons define the threat zone of the hazard as it exists at T+0 and the motion vector provides advanced systems with the information needed to progress the polygon through time

Subject event polygons define the threat zone of the hazard as it exists at T+0 and the motion vector provides advanced systems with the information needed to progress the polygon through time

Questions? Originators and Distributors will make assumptions realizing later several approaches exist Preset polygons deprecated? Alert message/Subject event polygons result in a distribution asset that is discontinued by not mapping as an asset in the polygon rather than an expires or cancel Alert message/subject event polygons result in a message possibly starting, continuing and ending for a specific location without an Alert or Cancel involved? Subject event polygons may require more frequent updates Will likely require the use of an PTF (Protocol Transfer Function)