An art that is also a science: Photography as a map-making device
By Ranjani Krishnakumar
Taking stunning photos is certainly an art — wildlife photography, action photography, more recently wedding / event photography — the career options are endless. Have you taken a moment to consider that photography is also the foundation of many scientific pursuits: map-making, archaeology, civil engineering, video games, and more!
Image of aerial photo of soil: the tall sand dunes in Namibia
Have you used Google Street View: the company’s virtual representation of your surroundings? This is done using a series of panoramic images. If you enable satellite view and press the 3D button, the perspective of the camera changes and you will see a virtual three-dimensional copy.
That 3D copy is made through a technology called photogrammetry.
What is photogrammetry?
Photogrammetry is measuring objects from images. Instead of using an inch-tape to measure the height of a building, we could take some pictures of it and calculate all its dimensions.
Photogrammetry is almost as old as the art of photography itself. In the past 150 years since its inception, it has been used for many things like measuring the dimensions of objects and the distance between two objects. It has also come very far, from analog to digital.
Measuring with pictures
If you take only one picture, you’ll not get much of a sense of the building — say how tall or wide the building is, or how big are the features at the center of the picture. But in the same picture, if you look elsewhere, you can see the sides of objects and get a slight sense of how big they are.
So in photogrammetry, you need to take two pictures from at least two different points, so you can get depth and perspective. This is also how 3D models work!
There are two different kinds of photogrammetry: terrestrial and aerial.
Terrestrial photogrammetry comprises of photos taken from cameras on the surface of the earth. This is what’s used for most of Google Street View. Google uses up-to-date camera equipment attached to cars, three-wheelers, trolleys, snowmobiles, and so on, so they could enter every space from large cities to narrow streets to inside buildings and atop snowy mountains and capture imagery in all these places.
Terrestrial photogrammetry has several applications in fields such as archaeology, paleontology, civil engineering, and even video games!
Video games? Yes! Remember the various worlds of Minecraft? The best-selling video game of all time, which inspired children across generations to imagine new worlds, draws significantly from photogrammetry. Since photogrammetry is so useful in constructing 3D models, they can also be used in facial reconstruction.
A model of Bill Gates’ face constructed using photogrammetry
When you think of archaeology and paleontology, you probably imagine scientists in the field, using a brush to delicately expose a valuable relic or ancient fossil, just like Harrison Ford in the Indiana Jones films, or Sam Neill in Jurassic Park.
But what about large fossils or large treasures that are expansive and cannot be wholly studied from up close?
Watch this video before you read further.
See? In the movie Godzilla, Matthew Broderick keeps asking everyone around him, “Where’s the sample?” But in reality, he’s standing in it — the sample is a large footprint of the iconic monster! And you can see the entire footprint only from the shot taken by a camera hovering far above the ground.
This is a direct application of aerial photogrammetry. It involves pictures taken from an airplane, helicopter, or more recently, drones, and are used to get a holistic view of and measure large objects, vast expanses of land, long distances, and so on.
While photogrammetry is not a word used in everyday conversation, it’s far more prevalent than you think. Apart from archaeology and paleontology, local and national governments use aerial photogrammetry to plot land, calculate where to construct new roads, make maps of different regions, and monitor natural resources — to name a few.
That GPS device telling you which way to drive is but a small part of a treasure of things that humans do with maps. They inform and influence a significant part of decision-making around the world. In fact, this is why ‘maps and navigation’ is an important part of the critical thinking module of the QShala program.
If you can read a map, you can go just about anywhere you want!