IMAGINE you're an adventurous Italian sailor in 15th-century Spain, and you're hoping to find a new route to the Far East - a place where you can make your fortune. You think you'll try sailing west instead of the normal route east. Some of your friends think this is impossible - you'll fall off the edge of the earth if you go too far. Should you go? This was Christopher Columbus's dilemma. Fortunately for him - and for us - he had a map. A rather crude, highly speculative map, to be sure. But a map nonetheless. We don't know exactly when it was that we humans first thought of making and using maps. But we do know that relatively sophisticated maps existed at least as far back as those created by the Egyptian geographer-astronomer Claudius Ptolemy, sometime around AD 150. And historians know of sea charts used by the Phoenicians of Syria in 1200 BC. Because maps today are so much a taken-for-granted part of our lives, it's actually difficult to imagine a time when people somehow managed to live without them, though they almost surely did. Back when people didn't move around very much, didn't travel more than a mile or two from their homes, there would have been little need for maps. To find one's way from here to there and back again, a few well-placed stones or marked trees would have sufficed. Before long, though, mankind was broadening geographic boundaries into areas far removed from parochial, home territories. Thus arose the need for maps. In simplest terms, a map is a picture-guide showing the location of and distance between two or more places, as each is directionally related to the other. So, to get to someplace you've not been before, you need know only two things: (1) where you're starting out from and where it is you'd like to wind up, and (2) where north, south, east, and west are. That's pretty much it. And you need a map, of course. Using a map is pretty easy. It's making a map that's the difficult thing. The people who do all the things that must be done to make a map are called cartographers. Part mathematician, part astronomer, part logician, part computer scientist, part draftsman, part meteorologist, and part artist, the cartographer must master such concepts as "meridians,parallels,projection," "latitude," and "longitude." And in the early days of mapmaking, the cartographer would also be part explorer too, since he was the on e who'd actually survey the areas that would then, back in the comforts of the cartographer's office, be put on the map. These days, though, the cartographer relies almost totally on information that already exists, much of which comes from photographs taken by high-flying satellites. So nowadays there are maps, maps, maps ... road maps, economic maps, population maps, topographic maps, nautical maps, and celestial maps ... and more. Enough to make super-Columbuses of us all. Let's consider briefly the terms "latitude" and "longitude," two of the most basic concepts the cartographer works with in drawing a map. Simply put, the earth, being a sphere, is divided into two halves by the equator, the imaginary "belt" that circles the earth halfway between the north and south poles. Latitude is your position north or south of the equator, measured in degrees of arc (from 0 at equator to 90 degrees at the north or south poles, each degree being about 69 miles). Circles running east to west parallel to the equator are called "parallels of latitude." "Meridians of longitude" divide the earth in imaginary circles that run from the north pole to the south pole. The so-called prime meridian, or 0 degree meridian, runs through an observatory at Greenwich, England, near London. The longitude of a certain location is found by measuring the number of degrees it is east or west of the prime meridian. IF you were the captain of an ocean liner and you had set sail from the port of Le Havre, France (located at approximately 49 degrees latitude north, a half-degree longitude west), bound for New York (located at about 40 degrees latitude north and 74 degrees longitude west), you would need to set your course right away. You'd first pinpoint the latitude and longitude of your position. Then you'd mark this spot on a map and draw a line from it to New York. That line would point in a certain direction - so uthwest, for example. You'd steer your ship in that direction, with the help of a compass, and would eventually come to the Big Apple. This all sounds pretty simple to us now, but it wasn't nearly so simple back in Columbus's day, when the tricky concept of "longitude" hadn't yet been worked out. It wasn't until the invention of the chronometer (a very accurate clock) in the middle of the 18th century that longitude could be precisely calculated. Before that, east-west points on the globe were arrived at by an "educated guess." Among the several navigational errors this resulted in was Columbus's belief that he'd sailed twice as far wes t than he actually had. It's said that he went to his grave still convinced that the land he found in the New World was actually the "Indies" in Asia. (Hence the name "Indians" he gave the native people he found here.) Most of us are not captains on ocean liners sailing the vast open seas, or astronauts piloting spacecrafts through the farthest reaches of the cosmos, but just need to get from downtown Toledo, Ohio, to downtown Bakersfield, Calif. We don't really need to know much about such technical matters as latitude, longitude, and degrees, and meridians. All we need is a good road map ... and enough gas in our car to get there, and some sandwiches, potato chips, and soft drinks for picnics along the way. So why don't you do just that. Imagine you're setting out with your parents on a trip that'll take you for the first time from your home in Toledo to your Aunt Bea and Uncle Harold's house way out in Bakersfield. (See if you can come up with the latitudes and longitudes for these two cities.) And imagine that your parents have given you the responsibility of being their navigator, the map-reading explorer who'll get you all there. One of the first things you'll notice is how very full of information your map is, how, inch for inch, it probably contains more facts than just about any other thing you can imagine. Which just happens to bring to mind a Mark Twain anecdote. In his book "Tom Sawyer Abroad," Tom and Huck Finn are up in a balloon wondering if they've passed over Illinois yet. Huck insists they have and Tom wonders how he knows. "I know by the color. We're right over Illinois yet," Huck says. "And you can see for yourself that Indiana ain't in sight." "What's the color got to do with it?" asks Tom. "It's got everything to do with it. Illinois is green, Indiana is pink... ." "Indiana pink? Why, what a lie!" "It ain't no lie; I've seen it on the map, and it's pink." "Seen it on the map! Huck Finn, did you reckon the states was the same color out-of-doors as they are on a map?" Huck, unfazed, sticks to his literal-minded view of cartography. "Tom Sawyer, what's a map for? Ain't it to learn you facts?" It surely is, even if, unlike Huck Finn, we should take with a grain of salt the "fact" that we can tell one state from another just by its color. Among the many facts your map does give you are the highway numbers you'll want to travel on and whether the roads are two-lane or interstate expressways. There are lots of routes you can take across a variety of states. How many can you find? The map should alert you to the rivers, mountain ranges, and deserts you'll cross. You should be able to see precisely how many miles between towns (and how large they are) and where one state ends and another begins. The map should even point out the various state -maintained rest areas where your family can have a picnic lunch ... and walk your dog. Well, after stopping three or four nights along the way in motels your mom picked, I bet, you've arrived at last in downtown Bakersfield. And your Aunt Bea and Uncle Harold live, your dad says, on Azalea Avenue. As your family's official navigator you'll need a different map, now. To find your aunt and uncle's house you'll need a map that shows every street that is in Bakersfield. Your dad's just now pulled into your Aunt Bea and Uncle Harold's driveway. You look toward their front door and see your Aunt Bea stepping out of the house wearing a flour-caked apron over her pretty pink dress (you hope she's just finished baking those oatmeal cookies that're your favorites!), waving her arms joyously, a great big smile spreading clear across her happy face. You've done it! You've navigated your family safely and surely all the way across the country with just two little pieces of paper. Mr. Columbus would be very proud of you right now.
'Kidspace' is a place on The Home Forum pages where kids can find stories that will tickle imagin-ations, entertain with a tall tale, explain how things work, or describe a real-life event. These articles appear twice a month, always on a Tuesday.