Ancestral Home pinpointed by DNA?

I noticed a link on Facebook via Family Tree Magazine's page:  "DNA sequences can trace your ancestors to within 30 miles."

Intrigued, I watched videos and read pages about Prosapia Genetics.  The DNA tool is called GPS:  Geographic Population Structure.  Some people have tried the service.

The site promised to pinpoint an ancestral hometown using data files from a DNA testing company.  I have already tested at 23andMe, so I uploaded my file to Prosapia for the result.  The cost was $29.99.  More expensive packages are available with a wider scope of possible populations.  I figured that I am mostly of European ancestry and these groups are fairly well-covered, so I opted for the lowest-priced package with fewer (200) possible groups.

There is no security certificate for this site, so that will dissuade some (and rightfully so).

Within minutes, my ancestral hometown was ready.  Well, the latitude and longitude coordinates were reported with a link to a labeled map on Google.

Prosapia Genetics

Google Maps
Hemmingen, Baden-Württemberg, Germany

According to Prosapia Genetics, my ancestral hometown is located on a farm in Hemmingen, Baden-Württemberg, Germany, to the southwest of Schwieberdingen.

I have not come across this town in my family history research.  My research does not go back one thousand years on any ancestral line, so it is entirely possible that I do have ancestors from this particular area.

This leads to another problem/question:  which ancestral line was from this area?  Which part of my DNA determined my connection to this specific area of the world?

I think that this GPS tool is an amazing idea and demonstrates how far DNA testing for genealogy has come in just a few years, but also demonstrates that more information and techniques are needed to draw accurate conclusions.