Is the world melting? Are these stills from an upcoming science fiction movie? Afraid not. It’s Google Earth experiencing an image-mapping glitch, thus creating some entertaining visual hiccups.
3D Images like those in Google Earth are generated through a process called texture mapping. Texture mapping is a technology developed by Ed Catmull in the 1970’s. In 3D modeling, a texture map is a flat image that gets applied to the surface of a 3D model, like a label on a can or a bottle of soda. Textures typically represent a flat expanse with very little depth of field, meant to mimic surface properties of an object. Textures are more like a scan than a photograph. The surface represented in a texture coincides with the surface of the picture plane, unlike a photograph that represents a space beyond the picture plane. This difference might be summed up another way: we see through a photograph, we look at a texture. This is an important distinction in 3D modeling, because textures are stretched across the surface of a 3D model, in essence becoming the skin for the model.
Google Earth’s textures however, are not shallow or flat. They are photographs that we look through into a space represented beyond-a space our brain interprets as having three dimensions and depth. We see space in the aerial photographs because of light and shadows and because of our prior knowledge of experienced space. When these photographs get distorted and stretched across the 3D topography of the earth, we are both looking at the distorted picture plane, and through the same picture plane at the space depicted in the texture. In other words, we are looking at two spaces simultaneously. Most of the time this doubling of spaces in Google Earth goes unnoticed, but sometimes the two spaces are so different, that things look strange, vertiginous, or plain wrong. But they’re not wrong. They reveal Google’s system used to map the earth -The Universal Texture.