Recreate Web Form that sends Google Map coordinates to email via .kml & .gpx attachments

I'm building a new site for an aerial photographer who needs a contact form that allows the user to draw a polygon area on a google map and send that data to him as a .kml and .gpx attachment. That way he can simply import the .kml or .gpx file into Google Earth. Anyone with experience with Google Maps API and Google Earth would be a huge help. I have attached a screenshot of the form we need to recreate. The only difference is we need it to be responsive and added to a Joomla site.