Did Dante's Divine Comedy describe or define Christian views on the afterlife? Dante's Divine Comedy, the 14th century epic poem describing a journey through the various levels of Hell, Purgatory and Heaven and the persons or types of persons who inhabit each level (including some of Dante's living contemporaries).  How much of Dante's description describes explicit Church doctrine as of his era, and to what extent, if any, did Dante influence Christian theology going forward?
The geography of the afterlife is not a topic where the church had "doctrine" as such, though there have always been a variety of traditions and stories about this sort of thing. Dante's scheme does reflect an underlying theology, so I'll tackle this from a theological perspective. The layouts of Hell, Purgatory and Heaven are all in some sense "orthodox" in that they are drawn from recognized classifications of sin and virtue. Dante does not claim that this is how things literally are in those realms - especially when we get to Heaven, and the entire scheme is reinterpreted several times, as he grows in understanding. The moral truth is what counts.

There are some specific areas where Dante does things which are novel, and sometimes opposed to actual doctrine.


The vestibule of Hell, an antechamber where the lukewarm, who were neither good nor bad, are stuck forever - this is new. If this area counts as "basically Hell anyway" then it's fine, since all souls are meant to be destined one way or the other. I think the lower levels of ante-Purgatory are also original to Dante, though I'm not sure about that. 
Saladin is placed among the righteous pagans, whereas as a Muslim he "ought" to be classed as at least a heretic or schismatic. Mohammed, for example, is placed in the eighth circle of Hell. This indicates some leniency from Dante about whether someone  who is aware of Christianity, but does not convert, attracts the maximum penalty.
Really bad people in the ninth circle (Inferno 33) are said to have descended to Hell while still alive, and their bodies are now possessed by demons. This is completely unorthodox, since standard Catholicism/Christianity holds that one can repent even in the moment of death.
The garden of Eden, or Earthly Paradise, is situated at the summit of Purgatory, which itself is a huge mountain directly on the other side of the world from Jerusalem. This is not completely new - Bede thought Purgatory might be a mountain, and the Eden-Purgatory association was also previously suggested, due to the common image of fire (the flaming sword of Genesis 3:24) and the restoration to primal innocence. The combination of this ideas is new, and Dante gave them a higher profile.


Contemporary doctrinal criticism of Dante was more about his politics, which were perceived as anti-Papal and anti-clerical. His idea of the division of responsibility between Pope and Emperor - a prototype for modern separation of church and state - was arguably heretical, even as late as 1864 and the Syllabus of Errors.