While debating the other day how panoramic maps were made, and the idea was brought up that cameras were used in balloons, and drawings made from the pictures. A Wikipedia article on pictorial maps has this to say "Edwin Whitefield for instance, one of the more prolific 19th century American pictorial map artists, would require about 200 subscribers before he put pen to paper. Once he secured the profitability of the venture, Whitefield would be seen all over town furiously sketching every building. Then, choosing an imaginary aerial vantage point, he would integrate all his sketches into a complete and detailed drawing of the city. Then after that, say the chroniclers of the time, Whitefield would once again be seen furiously darting all over town to collect from all his sponsors. Says Jean-Louis Rheault, a contemporary pictorial map illustrator: 'Pictorial maps - with their emphasis on what's important and eye-catching - make it easier to figure out what's where.'."
Full map at the Library of Congress can be found here.