|Date: ||Tue, 18 Mar 2008 08:37:30 -0700|
|Sender: ||"SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>|
|From: ||Jack Hamilton <jfh@STANFORDALUMNI.ORG>|
|Subject: ||Re: How to lookup zipcodes from longitude and lattitude of a city?|
|Content-Type: ||text/plain; charset="ISO-8859-1"|
Wll a centroid really suffice? If you use centroids instead of
boundaries, some assignments will be incorrect (a ZIP code area might be
partially or totally inside another ZIP code area). If you can't have
any incorrect assignments, you will have to use geocoding software.
It's available commercially, and there are (or were) some free programs
I wonder if that's something you can persuade Google Maps to tell you.
I don't know how, but probably someone does.
You might want to look at <http://maps.huge.info/zip.htm>,
On Mon, 17 Mar 2008 18:13:58 -0400, "George Joseph" <gjman@HOTMAIL.COM>
> If a hypothetical Tornado struck Beverly Hills High School, CA 90210 then
> you have the lat/long of the event (courtesy Google Maps for this
> Latitude: 34.06295236314582
> Longitude: -118.41236114501953
> If I understand zip code data correctly. The lat/long of a "zip code" is
> simply the centroid of the zip code. And the centroid is defined as: "A
> Code’s centroid is a point near the center of the areas of a polygon
> for a
> 5-Digit ZIP Code. The centroid is calculated as the internal balance
> based on the coordinate extremes of the polygon. In cases where the
> is irregular, the centroid may be adjusted so that ZIP Code labels never
> fall outside of the polygon."
> So Beverly Hills CA 90210 has a centroid of (Google for CA 90210 +
> Latitude: 34.096629
> Longitude: -118.412426
> I think you can get the lat/long of each zip code centroid from
> GIS vendors. We have one.
> So you are looking for a database which list EVERY possible lat/long in a
> given zip code. Since an "adverse weather" with a specific lat/long could
> fall in a zip code but NOT on the same centroid.
> You could try asking commercial vendors if they have such info or if you
> don't have much data you could manually create it.
> The question is: can you mathematically assign each lat/long to each zip
> centroid. In the above example the longitudes are the same (or the
> difference is zero) while the latitudes differ by 0.034. So how much
> their absolute difference be for you to assign them to a given zip
> centroid ?
> On Mon, 17 Mar 2008 13:15:00 -0700, vatodorov <vatodorov@GMAIL.COM>
> >Hi all,
> >The National Weather Service provides daily data for adverse weather
> >in the USA with the latitudes and longitudes of where an event has
> >taken place. I need to lookup the zip codes from the geospatial
> >coordinates. However, so far I haven't been able to do it. I tried
> >with the TIGER files provided from the Census Bureau, but to no avail.
> >Does anyone know how to lookup the zipcodes from the Earth's
> >coordinate system?
> >Thank you!