Mapping Operation War Diary – Bringing the Battlefields of Yesterday to Life
Recently, Steve Hirschorn at the National Archives has been looking at ways to visualise the information being generated by Operation War Diary Citizen Historians. As part of this work, he has taken maps found in the pages of the war diaries and, using the known coordinates of certain features contained within them, has fitted them to current satellite images using Google Earth. This process is known as georectifying and can help us assess how much the landscapes described in the war diaries have changed in the 100 years since they were written.
Over to Steve, who can tell you exactly how he’s done this…
Thanks to the efforts of volunteers using the #map hash-tag in the talk forum, it’s been easy for me to find georeference-able content. By geo-rectifying maps, it would be possible to use a GPS device to find the exact co-ordinates of anything that is documented in the maps, such as trench locations and routes, and machine gun emplacements.
Four KMZ (Google Earth/Google Maps) files are linked below. If you have Google Earth (free download available), you can use these files to view First World War maps overlaid on a recent satellite image. The KMZ files can also be imported into Google Maps, but the functionality via the website is more limited compared to the full Google Earth client.
After you have downloaded a KMZ file, you’ll see the war diary maps overlaid on the satellite view, but completely opaque. Look in the left-hand menu on Google Earth and by right-clicking an individual map item, you can select Properties and in the properties dialog box that appears, you can adjust the transparency from 0% to 100% and anywhere in between. I’ve tried to identify evidence in the current-day satellite images and street view photos of trench locations, but haven’t had much luck so far.
I’m amazed how well the most of the maps fit the current day landscape features. The odd road has disappeared here and there, but there are always enough reference points to fit the map, and they usually fit with just a bit of stretching and rotating, all of which functionality is also available in the free Google Earth client. A couple of them show trench locations (the map of Bullecourt) and machine gun placements (Ypres).
If you missed the link the first time, Google Earth can be downloaded here: http://www.google.co.uk/intl/en_uk/earth/
Steve’s map files can be downloaded using the following links:
- http://zooniverse-demo.s3.amazonaws.com/diaries_data/images/WO-95-1662-1_Bullecourt.kmz One of the better ones, a good fit to current-day road layout and showing the locations of trenches
- http://zooniverse-demo.s3.amazonaws.com/diaries_data/images/WO-95-1601-2_Ypres.kmz Another good fit, this time showing machine gun emplacements
- http://zooniverse-demo.s3.amazonaws.com/diaries_data/images/WO-95-1415-1_Hooge.kmz A map showing German trenches and the British Front Line
Lastly, as this is a new area of exploration for us here at Operation War Diary, and because none of us are experts on it, we have some questions which we hope you might be able to help us with:
- Is KMZ the best, most open format for sharing geo-rectified maps? Is there a better format?
- A bit of researching on the Internet suggests that there are ways of loading KMZ files onto a SatNav. Again, are KMZ files the best way of supporting this?
- Are there any web-based applications that enable geo-rectification of maps, and also provide a method of sharing geo-rectified maps?
- Do you have any geo-rectified maps you’ve created that you’d like to share?
- Are there any other ideas for things that we can do with the maps?
Post your answers in the comments here, or get involved on our forums at: http://talk.operationwardiary.org/#/boards