Hacking Historical Maps... or trying to

This weekend, I spent Sunday afternoon experimenting with solutions for historical mapping with Mia Ridge, a digital humanist and doyenne of hack days. We staged our own mini hack day to work through some of the challenges involved with the mapping side of my project on Parisian parishes, a major component of which involves geolocating demographic data to map the neighbourhoods in which artists lived in 18th-century Paris.

Over the past few years I've done the archival digging to come up with the data and now I'm at the stage of looking for the best ways to visualise it, both for research purposes (i.e. for me to use while thinking through and writing up the results) and for publication (i.e. how do you get copyright to publish a map in a book or journal article when you've built it on a commercial service like Google Maps?). Today we were mainly focusing on the first problem as it seemed the easier of the two, but ideally there'll be a single solution for both.

I experimented with two websites, Georeferencer and Hypercities, both of which I've used in the past, but today I was hoping to explore some more of their features. In the end, however, while both have some useful functionalities, neither was perfectly suited to my requirements (though it must be said that Hypercities seemed to have a bug that was preventing data from being saved so it was difficult to explore far). As you can see from the screenshot of my results with Georeferencer, I successfully georeferenced a fragment of an 18th-century map on Google Maps... but there was no way to geolocate historical data on it.

Mia experimented with Metacarter and Mapwarper, and has written up her results and experiences over at Open Objects. I have a major problem with sites like Metacarter because everything you produce is publicly visible, which obviously makes it very difficult when you're working with unpublished data. Most sites allow the option of keeping the maps you make restricted and that makes more sense for academics using these sites for research purposes. I'm excited to share my research when it's complete, but I'd like to have control over what happens in the meantime.

Administrative map of Paris, 1890 (Uni of Chicago Library)

So all-in-all I didn't discover the ideal open-access resource in a single afternoon (shock-horror) and for now I'll just have to keep going with the methods I've been using. But I have been able to pinpoint more accurately what it is that I'm looking for and what challenges I face in finding it. And as a happy bi-product we also discovered lots of wonderful sites providing access to historical maps that I hadn't encountered before, like the David Rumsey Map Collection and a great collection of 19th-century maps of Paris at the University of Chicago Library (most in high resolution with zoomify for getting into the detail of street level, as you can see in the screenshot).