Fifteen years after the assasination of President Kennedy, Dallas has overcome a negative, nationwide image and emerged as the No. 1 tourist destination in Texas, as well as one of the top three convention cities in America.

On any given day in Dallas, two things can be said with certainty: At least three conventions are under way, and a flock of tourists is standing in Dealey Plaza pointing toward the sixth-floor window of the Texas School Book Depository.

The national fascination with President Kennedy's assassination, which occured Nov. 22, 1963, is nowhere more evident than here. Rain or shine, cars with out-of-state plates park along the motorcade route as people make the solemn pilgrimage to the assissination site.

To be sure, Dallas residents bristle at the popularity of the School Book Depository. Natives try to steer you to new city hall - a trapezoidal creation designed by I.M. Pei- or to Thanksgiving Square, a sur-realistic park with fountains and a chapel by architect Philip Johnson.

Dallas would like to forget the past and the infamy it brought the city. But it has survived the period when citizens petitioned to tear down the School Book Depository. Last November, voters approved bonds to purchase the depository and turn it into a county office building.

However, uneasiness over the assassination lingers. When the School Book Depository is restored, the dreadful sixth floor and Lee Harvey Oswald's perch will remain empty.

"We want to make sure the sixth floor is not mishandled," explains a county official. "The further away we are from the assassination, the more objectively we can deal with it. . . . We don't want to do anything that might embarrass the city."

Dallas citizens clearly are embarrassed that the city's top selling postcard pictures President Kennedy's motorcade route, with each macabre detail of the assassination circled in red.

Nor is there much pride about the Kennedy Museum, a private venture across the street from the Book Depository. Open seven days a week from 9 to 5, the museum charges $1.50 and features a movie every 25 minutes. Called "The Incredible Hours," the film is a sensitive mixed-media presentation. However, the kitsch for sale and display throughout the rest of the museum appear to exploit rather than dignify the late president.

When John Neeley Bryan built a trading post on the Trinity River in 1841, he told folks he was waiting for his friends Dallas to join him. While he waited, he laid out a townsite half a mile square and sold provisions to the wagon trains rolling across north Texas.

Today, Bryan's log cabin sits on a grassy plaza in busy downtown Dallas, and a lot of folks are saying that Dallas has finally arrived.

With little more to market than the Texas mystique, Dallas has turned conventions and tourism into a $4 billion industry - the city's fifth largest, behind banking, insurance, oil and electronics.

To the conventioner, Dallas offers a welcome change from New York and Chicago, the other two leading convention sites (based on total attendance). Texas means barbecued ribs with Lone Star Beer, cowboy hats and Justin Boots, nachos and tacos and free-wheeling spenders buying mink and lynx despite the still, summer heat. ANd then there are the lower costs - $85 a day in Dallas, compared to $137 in New York City.

Dallas is also Texas' most accessible big city, given its north Texas location and the sprawling Dallas-Fort Worth Airport that opened in 1974. Situated mid-continent, the airport is just 2 1/2 hours from Los Angeles and Washington, or a post-convention jaunt to Acapulco.

Dallas-Fort Worth, and teh cluster of towns in between, have coalesced into the "Metroplex," an area that last year drew 3 1/2 million out-of-state tourists, predominantly from California and the Midwest, as well as 1 1/2 million conventioneers. Inside the Metroplex, they find dude ranches and rodeos, stock car races and chilli cook-offs, pro-ball games and dazzling 20th-century architecture - enough to keep them on the go for a week.

Dallas, the focal point of the Metroplex, is the perfect example of the Texas "big complex. This city of 880,000 calls itself "Big D," as in Big Apple - or, as rivals from Fort Worth might say, Big Deal!

Once called a "city of hate," Dallas surprises visitors with a down-home friendliness that market it easy to cash a check, or locate a dry cleaner who asks you name instead of giving you a number.

Even a mammoth downtown convention center, expanded in 1973 to draw the masses, has a personal touch about it. Right on the convention center grounds, with the Dallas skyline in full view, lies a quiet pioneer cemetery where crumbing grave markers identify early settlers as "Ma, Father, Baby and Son."

After visitors have made the pilgrimage to Dealey Plaza, it's time for more upbeat pursuits. "Hop-a-bus," a downtown shuttle service with 10-cent rides, stops at Neiman-Marcus, the posh downtown store where Stanley Marcus launched a retailing legend. Although the specialty store has lost its chic among the Dallas elite, it remains an elegant store where clerks who trained under "Mr. Stanley" still treat each customer like a millionaire.

For another glimpse of Texas life, catch the bus to the Dallas Farmers' Market, a sheltered downtown area where East Texas farmers wearing misshapen straw cowboy hats sell okra by the pint or peck. Women hull black-eyed peas, and ranchers wearing armadillo T-shirts display fresh jalapeno hot peppers. At the fringe of the market, an entrepreneur just in from West Texas offers large shoots of cactus for $1 apiece.

Dallas touts itself as a cosmopolitan city where the eastern half of the United States ends. However, the museums, shopping malls and revolving restaurant that the natives point to with pride can't compare with the fare back East. What is incomparable are the Mexican restaurants - more numerous than McDonalds - and the taco factories in Hispanic neighborhoods where you may buy oven-fresh tortillas or pastries filled with mashed pumpkin.

The best taste of Texas around is found in the small diners and cafeterias where the menu is regional: Texas toast (white bread sliced two inches thick); biscuits smothered in cream gravy, chicken fried steak (the Texas version of a wiener schnitzel); vegetale like okra, eggplant and even corn-on-the-cob dipped into cornmeal batter and deep-fried. For dessert there's pecan pie or apple cobbler.

Dallas residents love to point to their skyline, prominent for miles across the flat, dry plains. There's the old court-house, a landmark of red sandstone, and the Mobile Oil Building with two flying red horses on its roof. (They put two horses up there so no one could call Dallas a one-horse town.) The newest object on the Dallas horizon is Reunion, a 50-story tower of reflective glass and concrete capped by a geodesic dome. No ordinary dome, each of its points is lit up. At night, the dome blinks on an off, staging a repertoire of light shows - a traffic distraction to be sure. But the folks on the highway in their pickups and Cadillacs just love it.

According to forward-thinking Texans, Reunion Plaza eclipses the other sites in the city. But visitors curious about Texas' past may prefer Fair Park, 250 acres of lagoons, museums and entertainment arenas reminiscent of a less sophisticated Texas. Just south of downtown, Fair Park is the perfect place to stroll while sipping a soft drink and eating a corn dog - a hot dog on a lollipop sitck, covered with cornmeal and fried.

Although the midway at Fair Park has lost its crowds to nearby Six Flags Over Texas, it's a memory trip to walk through the spook house, ride the wooden roller coaster and circle round and round in the Western carousel. Constructed in the art moderne style of the late 1930s, Fair Park includes Cotton Bowl Stadium and the Texas Hall of State, a grandiose structure with little inside - a temple to the Texas ego.

If Fair Park whets your appetite for Texas of old, then it's time to journey 40 miles down the road to Fort Worth, a veritable Williamsburg of the West.

Every Saturday night there's a rodeo in the Cowtown Coliseum on Fort Worth's old North Side, where the streets are paved with bricks and the storefronts are straight out of a John Wayne flick.

Inside the coliseum, cowboys compete at bronco busting, steer 'rasslin' and calf roping. Down the street, along Exchange Avenue, Davidson's pawn shop features hunting guns and rifle racks for the back of your pickup. The Stockyards Drugstore displays a safe that was blown up by Butch Cassidy. Inside the A-1 Tattoo Parior, a young woman is having a rose etched on her breast. And next door at the Right Hotel, where rooms rent for $4 a night, the windows are dusty, the floor tiles are chipping away and the night clerk talks to patrons through an iron grate.

Across the street stands the White Elephant Saloon, a hip, country-western spot named for an old Fort Worth bar where lawman Long Hair Jim Courtwright was gunned down by Luke Short in 1887.

In those days, North Side Fort Worth was a stop along the Chisholm Trail. At the Livestock Exchange Building, the pace goes on as alwyas. Monday through Wednesday cattle auctions are under way, and at other times throughout the month, horses, hogs and sheep are sold at the block. The auctioneer talks as fast as a stampede, and the audience of ranchers raise each bid with the nod of a Stetson.

You'll know you're getting into the spirit of Texas if you saunter into a western wear store and find yourself buying a coyboy hat, boots or a pair of spurs. It happens to the most sophisticated people. Whenever Paris designer Yves St. Laurent visits Nelman-Marcus in Dallas, he can't resist a side trip to Fort Worth to buy a pair of "kickers." According to St. Laurent, his introduction of ladies fashion boots a decade ago was inspired by his visits to the Fort Worth Stockyards. And his line of snug "European fit" shirts are tailored after Western shirts, which are yoked at the shoulder.

It's just another manifestation of the Texas mystique that's luring people to the metroplex in record numbers. There's a curiosity about Texas that's contagious, and most visitors succumb.

A former resident of Silver Spring, travel writer Weiner now lives in Fort Worth and contributes to The Texas Observer.