I'd love to take a look at those UDFs. Do they work with any lat/long values? I'm asking because I have a DB with US zips and Canadian postal codes all with lat/long values (to about 5 decimals I think). The distance calculation that I found is a pig to put it midly, so hopefully the UDFs can help me out ;-)
TIA Bryan Stevenson VP & Director of E-Commerce Development Electric Edge Systems Group Inc. p. 250.920.8830 e. [EMAIL PROTECTED] --------------------------------------------------------- Macromedia Associate Partner www.macromedia.com --------------------------------------------------------- Vancouver Island ColdFusion Users Group Founder & Director www.cfug-vancouverisland.com ----- Original Message ----- From: "Tom Nunamaker" <[EMAIL PROTECTED]> To: "CF-Talk" <[EMAIL PROTECTED]> Sent: Friday, February 22, 2002 11:08 AM Subject: RE: List of Cities > The US Census agency has a free listing of lat/lon for zip codes at > http://ftp.census.gov/geo/www/gazetteer/places.html > > I wrote a bunch of UDF's for latlon calculations and posted them at > cflib.org about two weeks ago. I see they are still sitting in the > submission queue. <Why does it take two weeks to get to it guys?> > > If anyone needs the UDF's sooner, I can dig them out of the code I'm > using at www.morervs.com. Look at > http://www.morervs.com/fb3/index.cfm?fuseaction=search.home and try the > distance search. I think that's the kind of thing you're after. > > I haven't seen how others do this but my solution was based on the fact > that one degree of latitude is always equal to 60 nautical miles. You > take the distance for the radius of the search and convert it to > nautical miles. Then add that many degrees in a box around the starting > point. If my search was 138 statute miles (about 120 Nautical miles), > the 120 nautical miles is 2 degrees of arc at the earth's surface > (Assuming the earth is a perfect sphere). Do an SQL query to filter out > the vast majority of records that fall outside of the box surrounding > your origin... Something like > > Select * > >From myzipcodedata > Where lat between (targetlat-dist/(60*1.15)) and > (targetlat+dist/(60*1.15)) > AND lon between (targetlon-dist/(60*1.15)) and > (targetlon+dist/(60*1.15)) > > This leaves you with a rectangle that's CLOSE to a radius search. All > that's left to do is to loop through these records and actually > calculate the distance and throw out the ones that exceed your search > distance. One degree of longitude is only equal to 60 NM at the > equator. The farther North you go, the smaller the distance gets until > you get to the poles where it's zero. Your initial box to filter > records out is actually somewhat larger than your search distance but it > will never be smaller than your search distance. > > If someone has a better way, I'd love to see it but this method works > fairly quickly. > > Tom Nunamaker > Paladin Computers > Macromedia Certified Advanced ColdFusion 5.0 Developer > http://www.toshop.com/ > [EMAIL PROTECTED] > > > > > > -----Original Message----- > From: Jim Curran [mailto:[EMAIL PROTECTED]] > Sent: Friday, February 22, 2002 12:29 PM > To: CF-Talk > Subject: RE: List of Cities > > > Hi, > > There are zipcode lists with LAT and LONG coordinates for each zipcode. > > http://www.zipinfo.com/products/products.htm > > You can calculate your route's slope, distance and direction using the > codes, and then look up intersection paths in the DB. > > Hope that helps. > > I've done this before, and it is actually pretty exciting when it starts > working ;) > > - j > > jim.curran > technical.director > nylon.technology > 212.691.1134 > [EMAIL PROTECTED] > > -----Original Message----- > From: Duane Boudreau [mailto:[EMAIL PROTECTED]] > Sent: Friday, February 22, 2002 9:57 AM > To: CF-Talk > Subject: List of Cities > > > I am faced with a rather interesting challenge. > > I will be working on an application that will help a company increase > efficiency in shipping goods around the company. The company has its own > fleet of shipping vehicles but occasional will use independents for > small loads. > > What I need to figure out is if independent x from zip code z1 is > driving to zip code z2 what cities/towns does the route pass through or > close to (within 2 miles). > > TIA, > Duane > > > > ______________________________________________________________________ Dedicated Windows 2000 Server PIII 800 / 256 MB RAM / 40 GB HD / 20 GB MO/XFER Instant Activation · $99/Month · Free Setup http://www.pennyhost.com/redirect.cfm?adcode=coldfusiona FAQ: http://www.thenetprofits.co.uk/coldfusion/faq Archives: http://www.mail-archive.com/cf-talk@houseoffusion.com/ Unsubscribe: http://www.houseoffusion.com/index.cfm?sidebar=lists
