Inspired Stone

January 25, 2011, 4:07 am
Filed under: Mountain | Tags:

I recently discovered that airborne lidar data is freely available for a handful of US locations. And one of those locations: Yosemite Valley. That’s right, as a climber, I couldn’t have been happier. Visualizing the data is not a simple task. Airborne lidar data is produced by flying a plane low over the region of interest with a laser scanning over the surface of the earth. At each spot that the laser reflects off the ground, the elevation and position of the ground is recorded. The result is huge collection of x,y,z points blanketing the earth. It takes special software to manage the lidar data, primarily because a laser scan can easily produce millions of points. One piece of the Yosemite Valley lidar data covers the area around El Capitan with about 8.6 million points.

Thankfully there is academic work being done on lidar data and analysis and the software that has been developed is also freely available. Coincidently, the Institute for Data Analysis and Visualization here at UC Davis, is one of the organizations working on this topic and I used their LidarViewer and VRUI to visualize the El Cap lidar data. In addition, LASTools, developed at the University of North Carolina, provide a number of useful software tools to inspect and manipulate the lidar data (which has the file ending .las, hence the name LASTools).

The result of all of this is a cool 3D model of El Capitan.

There are holes in the data which I think were caused by overhanging sections of rock where the airplane mounted laser was not able to reach. I should also point out, that although the surface looks continuous in some places, it is actually composed of discrete points (about 8.6 million of them). You can zoom in quite close and see that the points reveal the fine detail in the cliff.

This is a close up view of the Alcove and Footstool

This one shows Mammoth Terraces and the Half Dollar


Sierra Crest :: Digitized
January 20, 2011, 4:03 am
Filed under: cartography, Mountain

Cartography is firmly in the digital age and has expanded into the field known as GIS, geographical information systems. Not a very exciting name, but it has revolutionized the way geographic information is presented and analyzed. Anything that can be related to geographic space can be presented on maps and analyzed for statistics or relationships. Want to know how the density of fast food restaurants correlates with political party distribution? I’m sure the answer is just a few mouse clicks away. Or how does highway and road density correlate with topography? Now that sounds interesting. Maybe someday, when I am more skilled with GIS software, I will answer that question.

As an initial foray into GIS, I decided to look at the topography around Mt. Whitney in the Sierra Nevada. In my science work, I manage and analyze spatial data and many of the same concepts apply to topographic data despite the radically different scales (nanometers versus meters). The difficulty was reconciling the different softwares and file formats used in molecular dynamics versus GIS. Once that was worked out, sort of, I started to have fun.

An image of the elevation on the 7.5 minute Mt. Whitney map (higher elevations are lighter), produced with qgis.

The image below shows the slope over the same area. The white regions are very steep and cliffy and the flat lakes are black. For climbers, images like this provide interesting research material. Although you can find cliffs on a topographic map by looking for places where the contours converge, I think it is even clearer in this presentation.

A 3D model of the east face of Mt. Whitney, produced with octave. I’m afraid it’s actually reflected north to south, but the idea is the same.

Lastly, a 3D model rendered in the molecular viewing program vmd. The surface is a sheet of balls because most molecules are represented as a collection of atoms, depicted as spheres.

January 16, 2011, 7:07 am
Filed under: cartography, Mountain

I’m fascinated by the crest of the Sierra Nevada. The Sierra Nevada, especially the southern High Sierra, are mountains of sharply defined ridges, jagged peaks and steep walls. As I alluded to in the post about aesthetics and climbing, there is something pure about the true crest of the Sierra. A rain drop on one side ends up in the Pacific, and a drop on the other winds up in the Great Basin. It’s mathematically well defined as well. Physical chemists talk about chemical reactions using the language of mountains, with it’s troughs and basins and saddles. While scientists are not usually interested in the peaks and ridges of an energy landscape, they are just as well defined.

To satisfy my curiosity, I drew a map of the Sierra crest, from Yosemite to Mt. Whitney. I tried to depict the crest as accurately as possible, with it’s connecting ridge lines, but the ultimate goal is not navigation, it’s inspiration. There is so much more that can be done with this subject: analyze it mathematically, depict it digitally, sketch it differently, traverse it…

January 13, 2011, 6:02 am
Filed under: Mountain

I’ve been scheming this adventure for the past couple years. The idea was sparked by reading Galen Rowell’s accounts of ski traversing two Great Basin mountain chains, the White Mountains of California and the Ruby Mountains of Nevada. In his fantastic book, “High and Wild”, he exposed the wildness, adventure and austere beauty of these desert ranges through his typically excellent writing and photos. I was inspired. But the White and Ruby Mountains are more significant endeavors than I’m prepared for. They involve on the order of 50 miles of traversing and peaks over 13,000 feet. I began searching for an alternative that had the same high desert flavor, but would fit my extended weekend time budget and novice skiing ability. The Sweetwater Mountains just north of Bridgeport, CA, fit the bill. An infrequently visited cluster of mountains, they would involve about 10 miles of traversing, 4 peaks, the highest being 11,200, and only about 4 hours driving from Davis. The possibility of spending one night in a hut sealed the deal. I was joined by 3 friends and we embarked on the 4 day adventure.

Of course, a necessary ingredient of any adventure is the unknown, and we discovered, upon arriving at the base of the Sweetwaters, that the two northern most peaks carried so little snow, that the trip would have become 50% hiking. Plan B: ski directly to the cabin (which turned out to be much further than I estimated for my companions and involved much skiing in the dark), and day trip up to the higher elevations. The highlights were the cabin with its blazing wood stove and the day skiing to the higher elevations which produced the best backcountry skiing I’ve experienced.