A moment in time: repeat photography to understand environmental change

“Historical landscape photography is the closest thing we have to a time machine,” says Professor Timm Hoffman, director of the Plant Conservation Unit within the Department of Biological Sciences at UCT. Hoffman has been collecting historical photographs of landscapes since the late 1980s and uses them to document environmental change. As  his collection grew, he ran into a storage problem which is when UCT eResearch provided him with centralised cloud-based data storage to house the collection.

Much of Hoffman’s research focuses on environmental change, and historical photographs are the best way to track that change over many years. “Once I have ascertained where the historical photograph was taken, I try and stand in the same place to retake the photograph,” says Hoffman.

“Timm was one of the first researchers to realise the benefit of centralised data storage. “The value of this service is that the storage is secure and reliable, backed up in multiple locations, and more cost- effective than a commercial cloud solution as it is centrally hosted by the institution.””

In this way he can analyse the changing landscape over the period of time linking what he sees in the landscape to climate models, so as to see if the landscape responds to the changing climate in the way the models predict. Over the years, and with the support of colleagues in the UCT Libraries and other departments, Hoffman’s collection has grown into a citizen science project called RePhotoSA. Members of the public can contribute to this project by visiting the site of existing historical photographs and taking their own images or by uploading their own historical images.

“We try to make the photos archival quality when we scan them”, says Hoffman. “But this means that a single file can be as big as 50 megabytes. When you have 20 or 30 thousand photographs, you very quickly run out of hardware space.”

“It takes only a second to take a photograph, but in that second you capture a resource so rich in information about the landscape. A collection of images can be used to build a narrative of what has driven change in that landscape over a period of time.”

“The ICTS team have been excellent in providing support for us, creating a specific drive in which we could work with the collection in the cloud”, explains Hoffman. “The space has been very stable and reliable and has been an absolute lifesaver.”

“Timm was one of the first researchers to realise the benefit of centralised data storage,” says eResearch Director, Dr Dale Peters. “The value of this service is that the storage is secure and reliable, backed up in multiple locations, and more cost- effective than  a commercial cloud solution as it is centrally hosted by the institution.”

Today RePhotoSA has about  6 000 historical photographs which are accessible to the public. These however are only the photographs that are suitable for repeat photography where the exact location is known. Hoffman’s collection is close to 30 000 images in total, dating from 1876 to the year 2000.

“It takes only a second to take a photograph,” says Hoffman, “but in that second you capture a resource so rich in information about the landscape. A collection of images can be used to build a narrative of what has driven change in that landscape over a period of time.”