hello- i would like to find a formula to determine all the zip codes in a radius. i have a database of zip codes and their GPS (lat/long) .

i have these fields

'zipcode',

latitude,

longitude',

zipcodesinRadius,

RadiusMiles

just trying to find out how this is done

Thanks

Dave

Hallo harter Mann,

there recently has been a thread just about that. Do a search.

at least this should solve the calculation of the zipcodesinradius field.

The other way is to use a geoquery web service via xml. Or mapquest, see www.tekstotaal.com .

The formula for the distance between points was given in another thread. To find all the zip codes within a certain distance from some central location, you will have to calculate all of the distances between the central location, and each of the zip code locations. Any zip code that has a distance less than or equal to the maximum allowable radius will be in the group.