New York City is 2.3 times larger than Atlanta.
Area: 346 km2 calculated
Atlanta is the capital of and the most populous city in the U.S. state of Georgia, with an estimated 2013 population of 447,841. Atlanta is the cultural and economic center of the Atlanta metropolitan area, home to 5,522,942 people and the ninth largest metropolitan area in the United States. Wikipedia
Area: 784 km2 calculated
New York is the most populous city in the United States and the center of the New York metropolitan area, the premier gateway for legal immigration to the United States and one of the most populous urban agglomerations in the world. Wikipedia