emergency-cap-profiles — archive

[Art Botterell]

CAP 1.1 actually provides for this, albeit in what may be too subtle a way. The "rule of primacy" says that the first info block in an alert that targets a particular location preempts subsequent ones. Thus the innermost zone in a nested-zone message would come first and would override subsequent, more broadly targeted infos. Obviously this approach has several potential side effects. In CAP 2.0 adopting a more complete subset of GML might allow explicit "cut out" areas within polygons... although that in turn might create some new potential pitfalls having to do with inadvertent gaps or overlaps among infos. I'd agree that this is going to require some careful analysis and is probably best left for the future. In the meantime, this best practical approach to this sort of complex geometry may be to use multiple distinct CAP alerts so as to avoid any ambiguity. - Art