Why historical maps remain as important today as the day they were scribed with quill and ink.

Our specialist GIS mapping department, CADS Mapping, is in the final stages of a project to georectify over 150 historical “Tithe Maps” for Hertfordshire Archive and Local Studies, the second project of this kind after the successful collaboration with West Yorkshire Archive Service’s “Tracks in Time” project in 2009. Here, Senior Cartographer Alan Walsh, highlights the lasting importance of these historical documents.

Anyone who watched BBC 4’s “The Beauty of Maps” would find it difficult not to agree with the sentiment that historical maps are vividly colourful snapshots of a landscape now forgotten. Their remaining value can only be determined by the age, rarity and aesthetic appeal. I’m not convinced that these are the only qualities which instil value in these historical document; a growing number of organisations are beginning to think the same way as they look to dust off the cobwebs and bring these historical treasures out of the archives and into the bright light of the modern age. Old maps are being reborn using the process of scanning and georectification, so that they can be accessed across digital networks, immeasurably increasing their accessibility, allowing the next generation a tantalising glimpse at the long forgotten foundations of our modern landscape.

Georectifa-what? is usually the first question so I will endeavour to explain.

A physical map is merely a piece of paper (or parchment…) with a series of lines and symbols printed upon it. You may be able to take a guess as to what those lines and symbols depict, but you are still left with the question where is this location? You could look for names on the map to give you an idea of where you might be but this method can be extremely unreliable. Did you know there are three towns in England called Standon? Four Coldecotes, seven Newnhams and there are Watfords in both Northamptonshire and Hertfordshire! Only the addition of geographic positional information (e.g. the British National Grid, utilised by Ordnance Survey products) gives the user a location to start using the map from.

The same rule applies to computer based mapping. The map image on screen has to be given a “real location” by assigning a series of known location points to it from a specified geographical projection or co-ordinate system (simply put, how the world is depicted when “flattened” from its global shape).

OK, so that’s the how? Next is the why bother?
There are many reasons that this process is important:

1. The first and arguably most important being conservation of the maps for future generations. Already many of the Tithe maps are beginning to show signs of wear and tear and in extreme cases have portions severely damaged or completely destroyed. In essence, creating high quality digital images of the maps stops the aging effects of time.
2. Secondly, once the digital image is created, it becomes much more accessible than the original physical map. Because of the delicate nature of these documents, their custodians have been extremely reluctant to allow access to them, fearing further wear and tear. A digital copy, accessed through a web portal, can be viewed by anyone, at anytime, anywhere in the world.
3. Finally, and the reason most relevant to me as a GIS professional, is that the digital copy becomes a useful tool to be used alongside modern mapping. Maps predating the expansion of the rail network before its subsequent contraction after the infamous “Beeching Report” in 1963 as well as barely recognisable road networks (the motor car was, in the case of some maps, still over 50 years away from being a recognisable mode of transport!) allow us to compare the old with the new. Villages, once the thriving hub of an agrarian past, vanish completely over the course of a century, absorbed by the expansion of towns, cities and the infrastructure needed for their sustained growth.

In the same way that TV programmes such as “Who do you think you are?” and websites such as “Ancestry.co.uk” allow us to trace our origins as individuals, these historical maps allow us to look at the origins of our surroundings, the places we know, the villages, towns and cities we grew up in, and to see how time and the progress of our society have altered our living environment.

That is their true value.

Alan.