The onrush of technology has allowed us to explore our planet in many new ways: in questing for directions, in locating via GPS, and in local browsing with hires maps and imagery. But perhaps the most revolutionary new dataset is the standardized elevation record from the Space Shuttle. It has instantly changed our knowledge of landscapes around the globe from rudimentary to analytical: radar altimetry from the mission in Feb 2000 has placed spot heights (SRTM) every 90m in x and y over the land portion of our earth between 60°N and 55°S. And with these patterns, the low cost archives and computer advances have delivered new views of where we live, where we wander, where we learn.
For the first time, in one look we can see a vast sweep of terrain covering a thousand miles, yet still we can explore at a neighborhood level of detail. Scales are just broader than would be the most generous eyeful of human perception (even from a jetliner). The prints can be very large so that the viewer will gain a zoom effect as an approach is made from a distance. The large sizes also emulate the subject in a suggestive way, and make the viewers feel a twinge of smallness.
I’ve used strong but respectful colors to show simultaneously the subtle terrain changes and the framework of broad patterns. Whenever satellite imagery is overlain, it is configured in natural color. There is no placed symbology or annotation, because the views need to be as unbroken and unlabelled as the ground itself. While each piece is rendered as a vertical view, true to map, I have often used a rotation from the usual North-up orientation, in order to improve a piece’s composition (also to match the imagery’s morning-time acquisition). Even with many years of practice, it is difficult to predict if any notional composition will ultimately succeed. It is almost as if the views emerge with their own embodied energy – after all, the earth is the artist here, and this site is a sampling tool, a periscope.
The SRTM elevations are a unique wonder. Testing and optimization lasted 5 years before a ‘best’ version was released in 2005 by NASA’s Jet Propulsion Lab. Still their fabric has holes for very steep terrain, and for both sandstorms and tree snow-ice coatings; it is unlikely that the huge effort will be revised from the start anytime soon. The NSA made a similar scale effort on their watermask datasets (SWBD), with shorelines drawn manually from millions of features on thousands of Landsat images.
What is shown? Some are of places familiar, but many more are arcane, made abstract in their obscurity, and chosen for their beauty of form, for the stories which they tell just by existing. The ridge patterns and drainage nets are at once strange and familiar, the villages scatter themselves as if in tension, and inkblots of megalopolis sit vaguely vulnerable in the wide sweep of nature. There are dunes of unusual character, deltas and rivers deserving repute, and many mixings of the recognizable and the “I-have-no-idea”. Plans include the expansion of the collection into the hundreds. The earth is huge, and thankfully for us it can now be more easily explored.
Below is an area north of Xian, China, part of an immense gully system carved through the ages out of wind deposits from the Gobi Desert. The top row shows elevation data with a gentle palette of unshadowed and shadowed form, and with an aggressive palette in shadowed form. At lower left is a natural color Landsat image of the same area, and to its right is its merged result with the shadowed elevation palettes above. It is my intent to display the near-normative character of the center element in the bottom row, to help each place show its fundamental patterns, rather than to make from each place something quite different.
Shown is about 10% of the vast complex, tributary to the Huang He River. The dominant soil of silt-sized particles (loess) has dual attributes of high fertility and extraordinary erodability to give the River’s annual floods an excellent renewal of crop suitability. This in turn has made the downstream North China Plain a cradle of agricultural initiative (among the earliest), and a driving force in the development of the Chinese civilization.