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GPS-ing
by By Fred Thorlin June 2000 HAL-PC , fredt@hal-pc.org - July 25, 2000 at 12:35:02:
You are Here!Who needs a GPS (Global Positioning System)? Now you do. Even if you don’t go adventuring in the great outdoors or sailing out of sight of the coast, it doesn’t matter. You need a GPS now.
A GPS is a device that can determine your location on the earth, based on information it receives from satellites. From that information, it can develop a lot of other handy information, e.g., your speed. These devices have been available since the late 1980s.
What has changed recently? At least one GPS has gotten so easy to operate, economical to buy, and reliable to use, that now I can’t imagine going far from home without it. Consider the following experiences:
• I visited a friend in Las Vegas. He gave me directions to his house, but I knew if I missed one landmark that I was in dire straits. Before going, I looked up the latitude and longitude of his house and entered it in my GPS. I intentionally ignored his directions and just went to where the GPS pointed. Following the arrow got me within 100 feet of his house. If I missed a turn, so what? I may not get there in the minimum amount of time, but on the other hand, I won’t have the frustration at not being able to follow his directions.
• Driving past the Sands Convention Center I pressed a button twice on my GPS. Two days later I got disoriented in the canyons behind the strip hotels. My GPS pointed me straight to the Center. The two taps were enough to record the location.
• I stayed with a friend in the mountains. His house was not visible from the main road and the entrance road was undistinguished. In the past, I had several times spent 20 minutes wandering up and down that road trying to identify his driveway. With the GPS, even at night, I found my way flawlessly.
The Magellan 315 is a big improvement over an earlier Magellan GPS I own. The 315 only weighs 7 ounces, is waterproof, and is available for as little as $135. It identifies my position quicker and hangs on to it through bad visibility better than its predecessor that cost twice as much. The new model provides more, and more useful information. It provides so much information you want to turn some of it off. Fortunately, you can.
The display shown in the photograph is the one I use the most. It also shows the Magellan’s clever way of overcoming a common complaint with earlier GPSs. The circle represents a compass, as you would expect. The arrow in the center points in the direction you are moving and the compass ring rotates around it. You can just make out the gray arrow also inside the ring in the photograph. It points to your destination as long as you are moving. But what if you are standing still? Do you see the two marks outside the ring? One represents the sun and the other the moon. Orient the GPS with the sun or moon, whichever is visible, and you will be correctly oriented, i.e., it now gives you the same information as a compass. A backlight is included. The text above the compass ring identifies the destination, declares the compass bearing you are moving along and the compass bearing of your destination. The last field tells you the distance to your destination in miles or kilometers. If you haven’t entered any destinatio ns, the unit comes with thousands of international landmarks already loaded. These range from Baytown, Texas to Veraval, India.
Another eight displays are offered for your insatiable appetite for navigational data. Some are interesting. One draws a map of your movements superimposed over your collection of landmarks. Another is a cute, animated odometer. One shows the orientation of locally visible navigation satellites. The others I don’t look at.
I am very enthusiastic about this unit, but it isn’t without flaws. The most serious one is there is no way of telling if your unit can still compute its position. This could lead to you to following it when it didn’t know where it was going. In practice, this hasn’t been a problem, but it is certainly a step backwards from the earlier models. The manual is weak. The database of cities provided is laughable. For unknown reasons, Magellan partitioned the list of provided cities into major, large and medium cities based on some demographic criteria. Unless you happen to know the population of the city you are looking for, you can’t predict which group it will turn up in. You end up searching all three. Try looking up Albany. There are three of them in the medium city group and one of them in the major city group, and there is no qualifying information, excluding latitude and longitude, to indicate you are selecting the Albany in Alabama, California, Georgia, Iowa, Illinois, Indiana, Kentucky, Louisiana, Minnesota, Montana or elsewhere! A really cool feature that reduces the severity of this problem is that the 315 will produce a list of the roughly, 20 closest locations in its database. There is a program, DataSend, available to load thousands of additional locations. It even includes about 20 restaurants within a few miles of me. On the other hand, the program is so flaky I didn’t attempt the transfer. I highly recommend the 315, just not the supplementary software.
The product works beautifully with Delorme Street Atlas 6.0 and, presumably, comparable mapping programs. I have looked up the latitude and longitude of several appointments here in Houston. I can then drive to these meetings without having to worry about missing a turn here or a landmark there. I now explore alternate routes and different areas of Houston without the slightest concern about becoming disoriented, which used to make me very frustrated. I am looking forward to my next trip to a strange city. I will be able to wander around completely at random without having to worry about getting lost in a strange land. At the Consumer Electronics Show 2000, I was told I could connect the 315 to a notebook computer running Street Atlas, and it would track my movements on the map just as well as if I had purchased Delorme’s yellow hockey puck that performs only that function. It was also indicated that an update to DataSend would be forthcoming.
On May 1, 2000 President Clinton announced that “selective availability (SA)” will be discontinued by 2006 and will be diminished immediately. SA refers to the error introduced into GPS data by the Department of Defense.
This can currently range up to 100 meters. With the removal of SA, other error sources will become significant, but we can look forward to their impact to be 10 meters or less. This will materially increase the utility and applicability of handheld GPS units such as the Magellan 315.
The Magellan 315, like most GPSs, is marketed to the offshore fishing crowd. There are features that are only useful in that context. There are some pricey GPS models intended for use in cars. Nonetheless, I think Magellan is missing out on a big market because the rest of us can make good use of their low priced GPSs now. If you do get a 315, I believe you will shortly start wondering how you got along without it.
Fred Thorlin is a long-term HAL-PC member and VB SIG founder, and can be reached at fredt@hal-pc.org.
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