You can also not think about the math, precompute the distance tables, and then only keep data in there where the distance is <x miles.
Russ > -----Original Message----- > From: Rick Root [mailto:[EMAIL PROTECTED] > Sent: Tuesday, February 06, 2007 3:10 PM > To: CF-Talk > Subject: Re: Transact-SQL help > > Actually, I did a limitation by longitude as well, because at the equator, > the fudge factor is the same (approximatley 69 miles per degree)... > everything in the US is less than that but I figured what the heck. So I > draw the box on both lat and long, knowing that the longitude will > actually > encompass MORE than the area I'm looking for... the getDistance() function > actually does the work of exact distances anyway. As long as the "box" is > bigger than necessary, it's all good. > > I was thinking it might actually be wise to use a range factor GREATER > than > 1/69 ... like 2/69...giving the latitude some wiggle room. > > But thinking about the math involved as to *WHY* I'd do that makes *MY* > head > hurt! > > > > On 2/6/07, Jim Wright <[EMAIL PROTECTED]> wrote: > > > > Rick Root wrote: > > > > > > I like how you're limiting by latitude only and using the radius as > > well. > > > > > > > Thinking about limiting it by longitude made my head hurt...I thought > > about using some larger constant (like the 2 degrees that you used), but > > in Alaska, 2 degrees longitude only equates to about 44 miles in some > > places. Limiting by latitude at least gets the bulk of the comparisons > > out of the way. > > > > > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Upgrade to Adobe ColdFusion MX7 Experience Flex 2 & MX7 integration & create powerful cross-platform RIAs http:http://ad.doubleclick.net/clk;56760587;14748456;a?http://www.adobe.com/products/coldfusion/flex2/?sdid=LVNU Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:268882 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4
