Humans have been fascinated by the view from above since the first aerial photograph was taken in 1858 by Gaspard-Fridayélix Tournachon (more commonly known as "Nadar"), high atop Paris in a hot air balloon. Since that first photo, the technology for taking aerial photographs has evolved dramatically and sometimes in unexpected ways. In the early years, photographers attached cameras to common unmanned flying objects such as kites and balloons. It might be surprising to learn that even pigeons were once used to capture images from the sky. Before planes became the common photographic vehicle, our feathered friends were incredibly important for aerial reconnaissance during the First and Second World Wars.
Sketch of Nadar in the Air Balloon (Published in Le Boulevard, 25 May 1862. Photo: Brooklyn Museum, 2004, via Wikimedia Commons)
Pigeon with Camera (Bundesarchiv, Bild 183-R01996 / CC-BY-SA 3.0 via Wikimedia Commons)
Aerial photographs allow us to see the evolution of a place over time. We can see neighbourhoods emerge, observe development patterns, and learn about the how the landscape has changed. Aerial photographs help us to understand how individual places make up the whole of the community and how that community has evolved over time.
The Science of Aerial Photographs
Did you know that human eyes can only see in two dimensions? It is an incredible trick of our brain that allows us to see in three dimensions, giving the world its depth. Our brain takes the two separate images from our eyes and combines them in a way that shows depth. This is called stereoscopic vision.
Aerial photography mimics this same process but uses an external viewer to put the images together. Aerial photographs are taken in such a way as to provide overlapping coverage of the ground. The plane flies at a set speed and photographs are taken at specific intervals to ensure the images overlap. The overlapping nature of the photographs (what is referred to as "stereo") enables three-dimensional features to be perceived from two-dimensional photographs. These overlapping images allow mapping specialists to get a sense of the relative height of buildings or natural features.
Today, mapping specialists use complex computer-aided design (CAD) technology to create these three-dimensional digital representations of what’s on the ground; but before computers came along, photographic prints were examined using a tabletop stereoscope that allowed for viewing two separate overlapping images at once. The eye is fooled into combining the two images and the result is that landscape features suddenly have the illusion of depth.
By using a tabletop stereoscope, mapping technicians would have been able to determine the height of the Port Mann Bridge - shown in these aerial photographs as it was being built in 1963.
Since the mid-20th century, Coquitlam has been taking advantage of the view from above to help with its engineering and planning decision-making. Coquitlam sourced the majority of its aerial photography from the Provincial Government, which has over 2.5 million air photos of British Columbia, some dating back to 1936.
Hundreds of these aerial photographs can now be found in the holdings of the City of Coquitlam Archives. The collection includes sets of aerial imagery from 1963, 1969, 1973, 1975, 1981, 1987 and 1991.
The set of 1963 aerials is now in the public domain and can be shared online. These incredible photographs have been digitized and can be found by searching in the City of Coquitlam Archives’ online search portal, Quest.
Even without a stereoscope, aerial photographs help us to see how Coquitlam has grown and changed over time. Take, for example, the area of Westwood Plateau, which today contains a vibrant residential development. Back in 1963, the area was home to the Westwood Racing Circuit, Canada’s first purpose-built road racing track that opened in 1959. The aerial photograph from 1963 shows the racing track - an elongated heart-shaped track cut out of the woods. Today, houses and the Westwood Plateau golf course stand on the famous corners of the track and some of the streets are named in honour of them (e.g. Deers Leap Place and Carousel Court).
Westwood Plateau, 2017 (City of Coquitlam, QtheMap Screenshot)
Mapping the Past - Slide Back in Time
In 2017, the Archives partnered with the City’s Mapping and Drafting Section to enhance access to the digitized 1963 aerial photographs. Using the City’s GIS technology (geographic information system), staff painstakingly mapped all of the historical aerial photographs from 1963 to the modern Coquitlam map. The result of their work is an incredible tool that allows researchers to slide back and forth between 1963 and 2017.
Merging old data with new technology can be tricky. Mapping technology has evolved dramatically since the early days of aerial photography. In order to map historical aerial photographs to our modern-day mapping systems, you must first ensure that all aerial photographs are oriented with North at the top of the photograph. Then, you choose at least two known spots on the photograph and match them to the same two known spots on the City’s georeferenced map.
"X" Marks the Spot, 1963
"X" Marks the Spot, 2017
The georeferencing tool in the City’s ArcMap program then rectifies the aerial photograph by stretching and rotating it to fit in the desired spatial location on the present-day map. It is like a jigsaw puzzle, with the various pieces overlapping and fitting together to form the complete image.
A Series of Georeferenced Photographs Pieced Together to Form the Complete Image
It can be challenging to make sure everything gets lined up properly. The edges of historical aerial photographs are often slightly warped and roads are re-routed or adjusted over time. The historical photos don’t always line up perfectly, but by merging them with our modern maps we are able to slide almost seamlessly from past to present and back again.
Special thanks to Mona Rudolph and Mike Esovoloff from the City’s Mapping and Drafting Section for their enthusiasm for this project and all their hard work to transform our historical aerial photographs into a dynamic online map.