Building a Geo-Coding Database and Website

OK, so this is my first ever public blog, so be patient with me.

I've written a few Perl related Genealogy programs including gedcom ( and ged2site ( One of the things that these do is to check the validity of your family tree, and one of those tasks is to verify place-names. Of course places do change names and spelling becomes more consistent over the years, but the vast majority remain the same. Enough of a majority to computerise the verification. Unfortunately all of the on-line services have one problem or another - most either charge for large number of access, or throttle the number of look-ups. Even my modest tree, just over 2000 people, reaches those limits.

There are, however, a number of free databases that can be used, including MaxMind, GeoNames, OpenAddresses and WhosOnFirst. The objective of Geo::Coder::Free ( is to create a database of those databases and to create a search engine either through a local copy of the database or through an on-line website. Both are in their early days, but I have examples which do surprisingly well.

The local copy of the database is built using the createdatabase.PL script which is bundled with G:C:F. That script creates a single SQLite file from downloaded copies of the databases listed above. Running 'make' will download GeoNames and Maxmind, but OpenAddresses and WhosOnFirst need to be downloaded manually if you decide to use them - they are treated as optional by G:C:.F.

There is a sample website at The source code for that site is included in the G:C:F distribution.

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About Nigel Horne

user-pic I blog about my projects.