Extracted from https://issues.oasis-open.org/browse/EMERGENCY-10 after a discussion in the CAP-SC meeting on August 20.
In the case a CAP message has multiple <area> blocks, it would be quite useful to define a single field that succinctly summarized all of the areas.
For example, we frequently see alerts with a long list of <area> blocks that correspond to existing political boundaries (zip codes, counties, warning zones) rather than defining the alertable area in a single polygon. In these cases, each <area> block has an <areaDesc> that describes that area. There is no field, then that summarizes the long list of areas to a single string.
As an example, NWS creates a severe winter storm alert with 5 <area> blocks, each with a geocode of a county in or around Atlanta. I'm looking for a single, optional field like
<areaDesc>Atlanta Metro Area</areaDesc>
It may be argued that CAP already supports what I'm looking for, if only NWS in this case used a single <area> block instead of 5.
Art Botterell comments on https://issues.oasis-open.org/browse/EMERGENCY-10:
By the same token, if the multiple areas can be described by a single label, they probably should be a single Area. In other words, I'm thinking we should look to help originators make better use the existing <areaDesc> field before asking them to populate another, potentially redundant element.
And of course having redundancy or semantic overlap among fields is almost always a bad thing in the structured-data context because it raises the problem of what to do if the two values conflict.
If that is the argument, then this issue becomes roughly the same as issue 10: What if a CAP author wants/needs to provide multiple granularities of area description (name both the counties and the metro area) in a single CAP alert?