Re: Zip code


"Philip Ronan" <invalid@xxxxxxxxxxxxxxx> wrote in message
news:BF0EE186.3577B%invalid@xxxxxxxxxxxxxxxxxx
> "News" wrote:
>
>> Thanks. While waiting for an answer I did a similar thing to the above
>> on
>> my own. All I did was calculate the delta latitude and longitude
>> (radius*360/24902) and added and subtracted from the center point. That
>> gave the surrounding box. From there I will have not that many zipcodes.
>> I
>> can test each one for distance and see if it lies within the specified
>> radius. That is the simplest method.
>
> The delta longitude will be a bit different unless you're at the equator.
> Off the top of my head, I'd say it's probably (radius*360/(24902*cos(lat))

Excellent point! Duh, I should have known that. After all, I teach Math.
Of course I will have to be careful with deg/rad. I will go no and look it
up.

Shelly


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