The most accurate info would be to get what the PSAPs have... Frank -----Original Message----- From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Peter Beckman Sent: Monday, September 20, 2010 9:23 PM To: Troy Davis Cc: VoiceOps Subject: Re: [VoiceOps] Rate Center Maps, Locations for NPANXXs On Mon, 20 Sep 2010, Troy Davis wrote:
On Mon, Sep 20, 2010 at 11:08 AM, Peter Beckman <beckman at angryox.com> wrote:
In the past I've paid MelissaData.com $400 or so to get access to their NPANXX-Ratecenter-Location-GIS data. For each NPANXX, they list the Ratecenter, City and state/region, Lat/Lon coordinates. It's fairly accurate, though I'm not entirely sure how they get the data.
We ran the ratecenter through Google's geocoder, in some cases with a bit ofB preprocessing and/or filters (state/county where known). But it's very much a best guess. Our goal with Digits has been to expose everything we can provide for free. Sometimes that's quite reliable (rate center), some of which is mostly accurate (carrier, city), and some of which is a crapshoot (lat/lng).
Those are cases of garbage in, garbage out. We start with mediocre data (ratecenter string like "WSNGTNZN17") and run with it as far as possible. Some ("SEATTLE") are easier than others :-)
I'd definitely consider replacing these lat/lng values with the CO lat/lng if you're able to find an unencumbered copy. I think you're right that they would be more accurate.
Actually I was saying in some cases it would be way inaccurate. Take 571-269. The CO is listed as Beltsville, MD, but the rate center is listed as being in a different state entirely. Using the CO lat/lng would confuse the issue. I used to think the CO lat/long would be more accurate, but I've learned otherwise.
As far as current accuracy, it depends on what you want to do with the data. It's completely unsuitable for making call routing or rating decisions. It's ideal for customizing/localizing IVRs, displaying inline maps, analyzing CDRs, deciding whether to offer a SMS menu choice, data appending, and the like, because all of those depend on depth of data and flexibility more than accuracy.
Yep. Though it would be great to try to get the City name normalized to a real city name, rather than NWYRCYZN01 for a ratecenter of NWYRCYZN15.
Regarding John Todd's note that wireless users and VoIP carriers have decoupled number from location, a byproduct is that for non-routing uses, that makes Digits about as accurate as anything else -- not because Digits is dead on, but because nothing else is anymore either. Digits might be 50 miles off, but there's a good chance that a wireless subscriber is 50 miles from their area code center anyway, so the API consumer already expects imprecision (except for routing).
Good catch, and thanks for the heads up. I just added geo_precision to the docs and examples, and clarified its meaning and where lat/lng come from.
Thanks for the clarification and link! I've started a wiki page on voip-info.org to try to put our collective heads together about regions and ratecenter names that don't map nicely to a city name. Any other thoughts are appreciated. I'll make it prettier tomorrow. http://www.voip-info.org/wiki/view/NANPA+Rate+Centers --------------------------------------------------------------------------- Peter Beckman Internet Guy beckman at angryox.com http://www.angryox.com/ --------------------------------------------------------------------------- _______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops