Exploring Horseshoe Canyon

Fall is an especially wonderful time in southern Utah. The weather is mild, the crowds are gone, and the cottonwoods are a brilliant yellow.  I recently spent a week  exploring such well-traveled national parks as Arches, Canyonlands, and Capitol Reef, as well as remote, out-of-the-way places where I was all alone.  As usual, I enjoyed the solitary spaces best, but the whole trip was inspiring.  I won't attempt to recount the entire adventure here.  Instead, in my next few blog entries I'll describe some of the highlights, starting with a strenuous hike through Horseshoe Canyon.

Canyonlands National Park is one of the lesser-visited national parks, and Horseshoe Canyon, a detached unit far to the west, is even more remote.  Horseshoe Canyon is famous for its haunting anthropomorphic pictographs, remnants of an ancient civilization known as the Barrier Canyon culture that died out centuries before the arrival of the earliest Anasazi basketmakers.  Some experts estimate the figures in Horseshoe Canyon to be more than five thousand years old. 

From Moab, it's a 4-hour drive: north on Utah 191 to Interstate 70, west on I70 to Utah 24, south on Utah 24 for 24 miles to the Horseshoe Canyon turnoff, then another 25 miles down a dirt road to a dirt parking lot.  Then it's a 700-foot descent and a six-mile hike through soft sand to reach the Great Gallery, the greatest collection of pictographs in all of North America.  Along the way, you pass several other sites nearly as grand.  When I was there I saw only one other hiker the entire day.

The figures themselves are enigmas.  Elongated human forms with no arms or legs stare blankly out from the walls.  Winged humanoid figures look ready to take off in flight.  Spirit-like shapes rise ominously over lesser figures.  What do they mean?  No one knows.  The featureless forms could be bodies wrapped in funeral blankets.  The winged figures and ghostly shapes could be visions conjured up by shamans during vision quests.  But this is only speculation.  No one alive knows for sure.

I spent an entire day hiking the canyon, exploring the rock art panels and trying to picture what it was like to live in this canyon five millennia ago.  The climate was probably more temperate--the earth was still emerging from its last ice age--but the canyon walls were no less steep, the rocks no less angular, than they are today.  And yet, the long-ago inhabitants of this remote canyon probably didn't regret their fate.  Game would have been plentiful.  Water would have run through the canyon year round.  And the environment would have been just as inspiring to them as it is to visitors today.

Next time you're in southern Utah, take a day to visit Horseshoe Canyon.  Bring good hiking boots, a camera, and plenty of water.  As you hike, take your time and look for the many pictographs along the way.  Just remember to only look, not touch.  Let's keep these ancient relics intact for those that follow to admire for another five thousand years.

Railroads Driving Airlines Out of Business

Now there's a headline you don't see every day. But according to Air Transport World Daily, that's the case in China, at least for certain domestic routes. Spring Air, a regional airline, has decided to cut back on short-haul routes of 600 miles or less because of heavy competition from trains. Separately, a China Southern Airlines spokesman commented on the benefits of rail travel compared to air travel: a better safety record, more convenience, and lower fares. This has driven China Southern to focus more on international travel in the coming years (though I'm not sure I'd want to travel any airline whose safety record isn't as good as a railroad's).

Here in the US, it will probably be some time before we see anything similar. With the exception of a few routes in the Northeast Corridor, rail travel in the US is not serious competition for the airlines. That may change in the future, though, as more federal stimulus money gets released. In California, the prospect of a high-speed rail link between Los Angeles and San Francisco is looking more encouraging, although it will be many years before it's complete. The expected 3-hour travel time would give airlines serious competition.

If you've ever spent much time in Europe or Asia, you'll recognize just how far behind the rest of the world our rail system is. Take the train from Frankfurt to Stuttgart, or from Geneva to Switzerland, or from Kyoto to Tokyo, and you'll quickly realize what a well-run rail system can offer. I doubt we'll ever again see railroads seriously compete for long-haul routes such as San Francisco to Chicago or Los Angeles to New York, but for those city pairs 600 miles or less away, it just might be possible.

Here's the link to the ATW Daily article: www.atwonline.com/news/other.html?issueDate=11%2F13%2F2009

GPS - Creaking at the Seams?

Regular readers of my blog know I occasionally update you on the status of Galileo, the European eqivalent of GPS. It’s been entertaining to watch the various factions argue about the cost of Galileo and its eventual fate. With luck, according to the current schedule it should become operational around 2013.

One of the major arguments against Galileo is that it won’t provide any capability that isn’t already provided by GPS. According to its critics, why waste billions of euros on Galileo when you can already get everything you need from GPS, for free? The US GPS community has taken a similar stance, amused that Europe thinks they need their own independent system.

Now it turns out that GPS might not be the rock of stability its supporters have made it out to be. A recent report issued by the US Government Accounting Office lists a litany of problems with GPS, some so serious that it is entirely possible the system may fall below the necessary minimum number of satellites as early as next year.

This might seem surprising since GPS requires a minimum of 24 operational satellites and there are now 30 in operation. But the report shows that 8 satellites are currently only one component away from total failure, and new satellites aren’t being launched as rapidly as old ones fail. Part of the problem is that the contract for the most recent satellites, the IIF series, was given to a new contractor, Boeing. (Previous series were built by Lockheed-Martin.) Boeing has experienced a series of delays and cost overruns that have put them almost three years behind their original schedule.

The one glimmer of hope is that in a typically conservative government approach, GAO’s concern arises because the probability of maintaining a full constellation of satellites falls below 95% for the years 2010-2014. That’s only a 5 percent chance of disaster. Nevertheless, for a system as critical to the world as GPS, that’s an unacceptably high risk. It just goes to show that maybe Galileo’s advocates have a legitimate case for why this potentially redundant satellite navigation system isn’t such a bad investment after all.

Pros and Cons of GPS-Enabled Smartphones

Now that cell phone technology has become ubiquitous in the new generation of smart mobile phones, the question on everyone’s mind is whether you can now get rid of your separate hand-held GPS receivers. If your primary use is highway navigation, the answer is a qualified “Maybe,” but if you use your GPS at all in the outdoors, the answer today is still “No.”

This might surprise some people. “My iPhone has a true GPS receiver just like a Garmin, so why should I need anything else?” they ask. The answer comes from design tradeoffs made by mobile phone designers. For the moment, don’t even worry about the fact a Garmin outdoor receiver is much more rugged than an iPhone. The fact is, the iPhone (and other GPS-enabled smartphones) won’t always find your position when you are far in the wilderness. I know. I’ve tried it, and it doesn’t always work. And if you do any amount of research on the Internet, you’ll come across many other people who have had similar experiences.

Before you say something like, “Steve, you must have a bad iPhone,” hear me out. The issue comes from a technology called “Assisted GPS” or simply “A-GPS.” It’s a great technology that allows the GPS in your mobile phone to find it’s position very rapidly. I won’t go into all the details of A-GPS here, I’ll just point out one tradeoff mobile phone designers typically make.

You probably know that a GPS receiver uses signals from satellites overhead to find its position. In order to do so, it needs to know precisely where in the sky each satellite is located any given instant. For this, it uses two sets of data stored in its memory about satellite orbits: almanac data and ephemeris data. Both almanac and ephemeris data need to be updated regularly because satellite orbits are never truly stable; there is always a small amount of variation as their orbits slowly decay. Also, new satellites are occasionally added to the system and old ones retired. The almanac data stored in your receiver’s memory remains valid for a few months, but ephemeris data needs to be updated every day.

The satellites themselves broadcast the almanac and ephemeris data for your GPS receiver to update its memory, but this is a slow process. Each satellite can only transmit the data at 50 bits per second (!). At this rate, it takes a minimum of 12.5 minutes to update almanac data and around 2 minutes to update ephemeris data. This would be a serious limitation for the typical mobile phone user, who expects to know his position within a few seconds.

Mobile phone designers realized they didn’t need to depend on the satellites to update the almanac and ephemeris data. Because their receiver is also a phone, they can simply program it to call up and get the current data from the network, where they’re not limited to a 50 bps transfer rate. This allows the GPS-enabled mobile phone to find its position much more rapidly than a dedicated GPS receiver, which can’t call up a network to get the data. (But beware, it also means you are transmitting and receiving data, for which you could be charged depending on your rate plan.)

This all works fine as long as you are within the coverage area of a WiFi or cellular network. But if you’re not, you could have real trouble. Here’s an example from my own experience. I was out on the Sonoma Coast with my iPhone, on a hiking trail well outside the range of a cellular network. I hadn’t used its GPS feature in a few days. When I turned it on, I waited and waited, and it eventually said it couldn’t find its position. I tried again and again, with no success. I finally gave up and drove to the nearby town of Bodega Bay, where I tried again. This time it had no trouble finding its position. Later, I went back to the same trail, and to my surprise this time the iPhone again had no trouble finding its position.

Here’s the explanation. When I first turned on the iPhone out on the trail, the ephemeris data was invalid because it was several days old. But since I was not in range of any kind of network, the iPhone had no way to get updated information, so it gave up. When I drove to Bodega Bay, I was again inside AT&T’s coverage area, so the iPhone downloaded the new ephemeris data and easily found its position. Then, when I went back to the trail, it already had current ephemeris data so it didn’t need to connect to the network to find its position.

The moral of this story is that if you’re going to use your GPS-enabled smartphone in the wilderness, make sure you give it a chance to acquire valid almanac and ephemeris data from a network before you head out. I haven’t done enough experimentation to know whether the iPhone will keep the ephemeris data updated from the satellites once it has found its position. This would have implications if you were planning to use it on a multi-day backpacking trip. I’d be interested in hearing from readers about their own experiences with GPS-enabled smartphones in the outdoors.