From Ric.Skinner@bhs.org Mon Mar 17 04:46:50 2003 Received: from mxu5.u.washington.edu (mxu5.u.washington.edu [140.142.32.164]) by lists.u.washington.edu (8.12.1+UW03.03/8.12.1+UW03.02) with ESMTP id h2HCknCK015846 for ; Mon, 17 Mar 2003 04:46:49 -0800 Received: from bhsexc1.bhs.org (springfield.bhs.org [141.154.134.25]) by mxu5.u.washington.edu (8.12.1+UW03.03/8.12.1+UW03.02) with ESMTP id h2HCkmIc001676 for ; Mon, 17 Mar 2003 04:46:48 -0800 Received: by BHSEXC1 with Internet Mail Service (5.5.2653.19) id ; Mon, 17 Mar 2003 07:41:45 -0500 Message-ID: <8243B9A9F4E44C4B996F6009E05ECE5E061F46BD@bhsexc2.bhs.org> From: "Skinner, Ric" To: "'waphgis@u.washington.edu'" Subject: RE: zip to county conversions Date: Mon, 17 Mar 2003 07:46:36 -0500 MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2653.19) Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Carlyn, The only way to be assured of accurate assignment of county, census = tract, block group or block -- or for that matter even municipality of = residence is to start by geocoding the full address to the street block face level = of geographic precision. Geocoding only to ZIP code results in the = physical residential address location (=3D situs) assumed to exist at the = geographic location of the centroid of the ZIP. In fact all addresses with the = same ZIP code would map to the same point (centroid). Especially for health = data, this is usually not acceptable. Tagging ZIP code geocoded addresses = with the any of the aformentioned areas (based on the location of the ZIP code centroid) oftentimes results in the address being "placed" in the wrong = area (i.e., county, municipality, etc.). Furthermore, geocoding based on a = P.O. or R.R. box number normally results in the address being placed at the location of the post office indicated by the ZIP code or ZIP+4. A more comprehensive and relevant discussion can be found in "Using Geographic Information Systems Technology in the Collection, Analysis and = Presentation of Cancer Registry Data: Introduction to Basic Practices" which was = written by the GIS Workgroup of the North American Assn. of Central Cancer Registries. This link is to a draft of the document. The final document = and its recommendations were recently accepted by NAACCR and it is in = finaling editing for publication. Link: http://www.schs.state.nc.us/NAACCR-GIS/handbookjune.html. Ric Skinner, Sr. GIS Coordinator=20 Health Geographics & Spatial Analysis Program=20 Baystate Medical Center=20 3601 Main St. 42=B0 07' 36" N=20 Springfield, MA 01199 USA 72=B0 36' 41" W=20 413-794-0662 (office) =20 413-262-2561 (cell) =20 ric.skinner@bhs.org=20 Associate Editor "Geographic Information Systems and Health = Applications" http://www.idea-group.com/books/details.asp?id=3D509 -----Original Message----- From: Orians, Carlyn E [mailto:orians@BATTELLE.ORG]=20 Sent: Friday, March 14, 2003 7:39 PM To: 'waphgis@u.washington.edu' Subject: RE: zip to county conversions Hi, A colleague of mine has a need to identify which county a given address = is located in. What he has to work with is standard mailing address data, including zip code. Has anybody discovered a useful way to convert = these to county locations? Any words of advice would be welcome. Thanks,=20 Carlyn Orians Senior Health Research Scientist Battelle Centers for Public Health Research and Evaluation 4500 Sand Point Way NE, Suite 100 Seattle, WA 98105-3949 phone:(206)528-3320 fax: (206)528-3550 orians@battelle.org=20 .