Sunday, August 26, 2001

By Cassandra Vivian

Want to know the exact location of the wreck of the Titanic? Easy! The Titanic wailed out its location at N 41 46 and W 50 14 the night it sank. How about the location of Princess Diana's grave? That's easy, too. It's N 52 17 15 and W 00 59 80.

Let's get closer to home. How about the location of Monessen, my hometown? Try N 40 09 678 W 79 53 924. That is right in the center of town. How about Washington, Pa., at South Wade and Maiden Street? That's N 40 10 078 W 80 13 348. How about the famous Cast Iron Bridge in Brownsville? Try N 40 01 280 W 79 53 316.

Welcome to the world of the Global Positioning System, the GPS. It's the Communication Age's way of getting around our globe. It is also a new form of independent and adventure travel: finding your way with a click of a button.

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Once geologists, geographers and even NASA experts roamed the Earth and searched the skies, making labor-intensive calculations to determine the exact location of a particular spot. Now anyone can pinpoint within a few inches the exact location of anything on land, in the sea or in the air.

There are GPS devices the size of cellular phones that you can take on desert journeys, hiking trails or paddling lakes. Others are designed exclusively for hiking, climbing or exploring. Some have maps you can download.

A businessman can rent a car in an unfamiliar town and find his way to his hotel or meeting place by using the GPS attached to the dashboard. Hikers along Warrior's Path, Forbes Road or any of the dozens of woodland trails in southwestern Pennsylvania can stay on the path without getting lost. Fishermen can located their favorite spot on Lake Arthur or Lake Erie and return to it again and again to try to catch the "one that got away."

Going for the cache

In fact, a new kind of treasure hunt has been developed. It is called the Geocache. One person hides a treasure trove, complete with logbook, in some remote or interesting location and posts it on the Internet at www.geocaching.com. Another person looks for a good way to spend a Saturday afternoon with family and picks one of the posted hunts. They type the coordinates into their GPS, get in their car, and follow the GPS coordinates to the destination.

Sometimes they have to walk the final feet, yards or miles, but once they find the location, they can open the cache and write their experience in the logbook for others to find. Some treasure masters leave objects in their cache. The hunter can take an item and replace it with something of equal value: batteries, flashlights, midget footballs and the like.

Geocaching is just catching on in the Pittsburgh area. There's no organization to join. Just log on, pick a state or a country, and go Geocache.

How it works

The U.S. government developed and maintains the Global Positioning Satellite System. Twenty-four NAVSTAR GPS satellites circle the Earth 12,000 miles up in the sky in precise, 12-hour orbits. They not only transmit their location but also they tell the time based on an onboard atomic clock.

When a GPS device is turned on, it sends a signal skyward looking for these satellites. Once it finds three of them, the device can pinpoint its earthbound location precisely by using triangulation, using three known locations to locate a fourth. Once this is done, the adventure is marked forever.

If you have any geographical sense at all -- and many of us do not -- by now you are getting the drift. N is obvious, or should be, for it stands for north. And if N is north, well you know what S, W, and E are. So north of what? North is north of the equator. This is latitude. East or West is east or west of the Prime Meridian in Greenwich, England. This is longitude.

All of the imaginary lines we have set up around the world in latitude and longitude directions are called meridians. To remember which is which just think of longitude as being "long," because all its lines are the same size and must run through the two poles. That makes longitude lines longer than latitude, which has lines that grow smaller as they move closer to the poles .

In addition to latitude and longitude, the GPS also records altitude. Then it tells you your current speed, your track, the day and the time. If you follow the same route back to where you started, it tells you not only how to get there, but also how far you are from the next point in miles or kilometers, and how long it will take you to get there at your current speed.

No more kids asking, "Are we there yet?" They can follow the GPS on the dashboard.

40 29 and 633 you say?

It's time to explain just what all these numbers mean. The first numbers in our waypoint indicate the degree of the site. If you are a duck sitting in the water just off the point in Pittsburgh where the Allegheny and the Monongahela collide, you are at N 40 26 499 W 80 00 892.

The first set of numbers means you are 40 degrees north of the equator and 80 degrees west of Greenwich. The second set of numbers take us closer, as they give us the distance in minutes from the degree. The third set of numbers takes us into seconds.

Pittsburgh's Point is 40 degrees, 26 minutes and 499 seconds north of the equator and 80 degrees, 00 minute and 892 seconds west of Greenwich. Got it?

GPSing to the wall of Forbes Field

So, you have never been able to find the old wall at Forbes Field, and since it is the only piece of that great stadium still standing in Oakland, you want to see it. Or better yet, you want to go meet the fans who gather there each October to listen to the seventh game of the World Series when Maz hit the shot heard round the world. It is not the easiest place to find in Pittsburgh.

Here are the coordinates: N 40 26 475 W 79 57 185. Input the waypoint into your new GPS, and set it on your dashboard so it can scan the sky. Flip through the screens until you come to the one that will lead you to Forbes Field.

Let's say you're coming through the Liberty Tubes at N 40 24 859 W 80 00 572. Then you cross the Liberty Bridge and move up the Boulevard of the Allies on to Forbes Avenue. You have to concentrate only on the changing seconds: from 475 to 185. You are that close. You zoom past the "O" and screech to a stop at the Dippy the Dinosaur outside Carnegie Museum. Its coordinates are N 40 26 615 W 79 57 095. You have gone too far.

The waypoint for the wall ends in 475 seconds. The wall is behind you. You cannot do a U-turn, so you go around the block and zoom across Forbes. When you reach the lower end of the parking lot, you are very close. You can see the wall to your left. But you are not in front of it. So, you circle around again making a wider sweep until you stop exactly at: N 40 26 475 W 79 57 185. You are there.

Take care

Now the reality of GPS is a little more complicated. Buildings may be in the way of your destination, and streets may be one-way. In remote areas, mountains and rivers may present obstacles. You cannot follow the GPS in a straight line from one waypoint to another. Your GPS device might have trouble finding the satellites if too many tall buildings, trees or cliffs are nearby.

If you run out of battery power and forget to bring spare batteries or the spares are no good, you also are out of luck.

Handling a GPS while driving is worse than using a cellular phone. You need a sidekick. If you foolishly go into dangerous territory without a secondary source of help or proper backup, you can get lost. It might not be important in urban Pittsburgh, but it will be when you are hauling a deer back through a Pennsylvania forest, or are in Ghana, looking for the campground called Big Milly's Backyard (N 05 29 752 W 00 21 930).

Because I put GPS in my book on the Western Desert of Egypt, a fledgling travel agent called me and said, "I have a client who wants to go to the Gilf Kebir. What are the coordinates, and do they have gas stations along the way?" Now the Gilf Kebir is a plateau with no roads to it, no water around it, no food anywhere and no people for hundreds of miles. "Are you out of your mind?" I screamed at him. "You can't go! Turn them over to a tour operator who does this work!" You must respect the power the GPS gives you.

The future

Although GPS is in its infancy, already it is a sensation. Soon a second set of signals will come from the satellites, expanding the civilian use of GPS. The development of the Intelligent Transportation Systems the ITS will integrate the GPS into our daily lives more and more.

Hertz, the car rental agency, and Magellan, a GPS company, have joined forces to build GPS into more and more vehicles. These smart GPS's not only look at routes and determine the best way to go but also speak out their directions so you will never get lost while looking for cousin Mary's new home or the site of the field house at Penn State or WVU.

In the future the grandchildren of our GPS's will actually drive while we sit back and read the paper. Someday a GPS will be a part of everyone's Palm Pilot, cellular phone or Internet connection: one more system to carry in a single hand-held unit. We will have to explain to our great-grandchildren all the funny gadgets we are now carrying in our purses or on our belts. They will never understand how we got lost while going to Grandma's house for Thanksgiving.

Where do I get one?

You can buy a GPS at sporting-goods outlets, K Mart, WalMart, high-end specialty stores and boat shops. You can find a special GPS for mountain climbing, another for trekking and a third for exploring. Larger models have fish trackers and navigation GPS with waterway maps.

The companies that dominate the market are Garmin, Magellan, Phillips and Lowrance. A hand-held model runs anywhere from $100 to $600, while a larger mounted model is more expensive. You can hook them up to your computer and upload waypoints and tracks onto maps or find waypoint URL's and download to your heart's content.

Cassandra Vivian is a writer and photographer who lived in Egypt for many years Her book "The Western Desert of Egypt: An Explorer's Handbook" was recently published by The American University in Cairo Press and is distributed worldwide. More than 200 GPS points in the book cover everything from Cairo to thxe remotest region of Egypt's desert. She will be expert-in-residence of a British tour to oases and the Western Desert in January and March 2002 and a more aggressive deep desert German tour in February 2002. For info contact her at cass@telerama.com.