Way to Geolocate Files by Date Created

Does anyone know of a way (programmatic/Terminal or GUI) to geotag files using GPX files the way that Aperture can do for photos?

(I'm basically trying to create my own "Atlas" function from Evernote, for those who are familiar with that feature.)

I'm thinking the way to do this would be to create custom latitude and longitude extended attributes that correspond to the GPX file based on "date created," but I'm not exactly sure how I would go about this without doing it by hand. (I have done a few by hand using xattr.)

Any thoughts or help would be appreciated!