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Subject: Re: [emergency] Talking Point re CAP and CEA "Public Alert"
At 2:19 PM -0700 4/8/04, Kon Wilms wrote: >The only compatibility I see is that at some point in time the Public Alert >message elements can be stuffed into a CAP message for transport on headend >networks. Right now that's right. It's a backward compatibility challenge that we're addressing at the content level. And saying CAP is compatible with Public Alert (or NWR, or EAS) is not the same as saying the reverse. Obviously it's going to take more than a couple of weeks for the existing public warning infrastructure to convert to CAP. Fortunately (and by design) it's not an all-or-nothing proposition. And looking at it politically, if we want uptake for CAP, seems like we may want to avoid appearing to detract from any of the major existing players. Instead, we may want to emphasize how CAP can make existing systems even better. Over time, I'm confident the benefits of CAP will become clear to everyone and its use will become more pervasive. >It isn't compatible with the NWS system from the point where one can just >take an NWS message like EMWIN products and stuff them into a CAP file. True, because NWS doesn't enforce strict structures for their text products. The current NWS text system comes from a tradition of "rip-and-read" teletype copy meant for human reading, not for easy computer processing. NWS management are well aware of the huge variations in how different forecast offices format their products, but it's a huge organization and change takes time. Besides, until now there wasn't an industry standard available... and the current administration is very much oriented toward industry-generated standards. There's been progress: The LAT...LON convention for describing precise target area coordinates in "short fuse" warning products is being used pretty consistently... and the "bullet" format used by a number of offices for warnings can be mapped fairly precisely into the component elements of a CAP document. And their experiment using CAP suggests that NWS is actively considering moving to more structured formats. But in the meantime it's a little like copying VHS to DVD... the output product can't be any better than the input. The best we can do is make sure that we can accurately reflect the input, however structured or unstructured it may be. >I don't see any CAP compatible files coming over the GOES satellite feeds >(thats the real stuff I care about - test feeds are good for demo only). NWS has a whole process they have to go through to adopt new technology. The first step is an "experimental" service, which is what they're doing now. So if you want CAP feeds by satellite, I'd encourage you to communicate your support to Bob Bunge in the NWS CIO's office (<robert.bunge@noaa.gov>) so he'll have ammunition to persuade his management to take that next step. >CAP and XML in general is also >too wordy to transmit quickly at a low datarate - the 3000+ products that >are transmitted at 2400 and 9600bps over GOES would never come through in a >timely fashion if they were all reformatted to CAP spec. This objection comes up regularly... but as you've demonstrated, XML compresses really well, and that's a fairly routine, standards-based solution. >CAP is only compatible with the NWS system when the NWS decides to reformat >all their products to CAP and starts distributing them over their satellite >feeds. This is just my opinion, however. Get your point, but I think that may be putting the shoe on the wrong foot. We're the new guys on the block, and we're taken pains to be compatible with the old established systems. We can hope to see a migration toward more modern methods as the benefits of CAP are demonstrated, and as consumers start asking providers to make the move. - Art
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