[CAP] multiple infos faq entry

[Art Botterell]

There's another significance of multiple info blocks that I don't think can be replicated in multiple separate alerts, at least not in CAP 1.1.  

Where multiple info blocks also can be used to describe different messages (descriptions, instructions, responseType, etc.) for different and potentially overlapping areas... e.g., concentric evacuation and shelter-in-place zones, probability bands for storm strike predictions, etc... then multiple info zones combined with the specified "rule of primacy" allow CAP 1.1 to represent complex geometries ("donut-holes" and the like) without using a more complicated geospatial syntax in the area block.

It might be time to move to a more complete GML-style geospatial form for area blocks.  In that case, we could revisit the use of info blocks and consider restricting them to the Canadian (language-only) or other usages.  However, a lot of folks still seem to find even simple geospatial geometries intimidating, so I wonder whether the market is entirely ready for that.

- Art


Art Botterell, Manager
Community Warning System
Contra Costa County Office of the Sheriff
50 Glacier Drive
Martinez, California 94553
(925) 313-9603
fax (925) 646-1120