This is a latitude-longitude map of the surface of Titan, using the data collected so far with Keck speckle imaging . The trailing hemisphere is mostly dark, with darker regions near the equator. Haze particles form by photolysis of the Methane by sunlight and are suspended in the upper atmosphere.
Larger particles rain down on the surface.
The balance of chemistry in the atmosphere gives clues about the surface composition. Light reflecting off the haze particles prevents seeing the surface at most wavelengths. Data interpretation requires separating the the atmosphere from the surface light. The atmospheric light properties tell about the haze and Methane abundance and vertical position. The surface light tells about the composition of the surface.