With the emergence of Google Earth, you may be familiar with satellite images and the “view from above.” But do you know what this view looked like 50, 60, or 70 years ago? Staff at the University Map Library have recently initiated a project to digitize historical air photos of Waterloo Region that will show just this, while also increasing the usage potential of the photos through georeferencing.
Since November 2007 staff at the Map Library have been busy scanning, archiving, and georeferencing black and white air photos taken during the years of 1930 and 1945-47. With copyright retention set at 50 years after the date of publication, the Map Library has over 900 photos in the public domain within these years and has already digitized over 650 to date.
While the Aerial Photography Digitization Project has the obvious archival benefit of ensuring that the images will be preserved and made available for future generations, the georeferencing aspect of the project amplifies the photographs’ usage potential.
As Geospatial Data Services Librarian, Eva Dodsworth, notes “Aerial photography captures moments in time, offering a pictorial preservation of history. Georeferenced aerial photography accurately puts the photograph on the earth’s surface, making the information richer, more connected, and more revealing."
Georeferencing increases the usage potential of static images by adding location information (latitude and longitude coordinates) to the photos that enables them to be added to Google Earth, a geospatial information system, or any software that reads spatial information.
Consider how georeferencing has enabled additional information to be overlayed onto these photos:
|This image shows a georeferenced air photo of Kitchener from 1945 overlaid with current streets. (Streets courtesy of the Region of Waterloo)|
|This image shows a georeferenced 1945 air photo of Kitchener overlaid on top of a current satellite image in Google Earth. Notice how the streets in both images line up.|
With the digitization aspect of the project scheduled for completion in March, georeferencing will continue until completed. Eventually the project’s focus will shift to making these photos deliverable through the web, with the goal being to provide users with access to these images in a format that will enable them to stitch images together and overlay them onto Google Earth.
Eva notes, “We hope this project will be well received by both university and community users and that it will pave a path for other map libraries to share rich resources that are currently archived with lock and key.”
For more information on the project, contact:
Geospatial Data Services Librarian
University Map Library