If we were to construct the most solid argument for the proposition, it would be to say that fiction provides the initial spark, inspiration, and that travel guides are just tools to realize this pre-existing vision.
However, it is important to note that this hierarchy is often more nuanced than it appears, especially in terms of impact on the final decision.
A guide can very well be the primary source of a desire to travel, not just a planning tool post-inspiration.
For example, a friend discovered the charms of Art Nouveau architecture in Brussels not through a film, but by browsing a thematic guide that sparked his curiosity, thus becoming the initial trigger of his trip.