Polygons What are Preset Polygons Alert Message Polygons

Polygons • What are… – Preset Polygons – Alert Message Polygons – Subject event Polygons • What is Bias? • What is Best? • What is a motion vector? Page 1 – 2021 -03 -06

Preset polygons translate to geocodes in a CAP file that then make heavy use of lookup tables (common in non-GIS CAP based systems) Page 2 – 2021 -03 -06

Alert message polygons define the area to be alerted (used when mapping to broadcast assets within the affected area) Page 3 – 2021 -03 -06

Subject event polygons define 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 Page 4 – 2021 -03 -06

Questions? • Preset polygons subject to heavy over-alerting • Preset polygons subject to maintenance overhead • Alert message polygons define the area to be alerted (when mapping • • • to assets within the affected area) Alert message polygons more likely in public alert based systems Subject event polygons require advanced interfaces to message originators Subject event polygons more likely in incident management systems Subject event polygons can be converted to the other two but this would require two or three alerts Subject event alerts and Action based alerts – Fire zone vs. Evacuation zone – Contaminated Water zone vs. Boil Water zone • May require the use of an PTF (Protocol Transfer Function) Page 5 – 2021 -03 -06