I am sure this will be a fun tool, and useful for some purposes,
but be careful not to misinterpret the results.

The tool shows when the surname first appears in JRI-Poland
records in a town, not when the surname first appeared in the
town. For many towns, JRI-Poland does not have records >from
the early 1800s and its coverage starts later.

So you may really be seeing how JRI-Poland's coverage spread
to more of the towns where the family was already living, not
seeing when the family first moved there.

Stephen Weinstein
stephenweinstein@yahoo.com
Camarillo, California, USA

Stanley Diamond wrote:

Jewish Records Indexing - Poland today announced the "Surname
Distribution Mapper" - a tool designed to help genealogy
researchers graphically understand where their family names first
appeared in the 19th century records and visualize how the family
spread throughout Poland by decades >from the early 1800s into the
first part of the 20th century....