Batman/Judge Dredd crossover question

I’ve just finished reading the Batman/Judge Dredd files, a colection of crossovers between DC and 2000ad. In it, Batman is zapped to mega city one, in a different dimension. My query is this: is Megacity one in another dimension?? I always thought that Dredd’s world was just our own, several hundred years in the future. Therefore, it would have been easy for the writers to say that Batman had been zapped into the future, and not another dimension, thus ruling out any headaches with alternate earthsetc. Did the writers not take this into account? It seems to me they just came up with some bullshit so they could team up Dredd and Bats. My DC is pretty shaky, and my 2000ad non-existent, so I’m basing my theories on what I believed to be the story of Dredd and Mega city one. Can anyone give me a better outlook?

I don’t really follow either, but I’m guessing it would have been difficult to explain how events that led to the current state of the Dredd world hadn’t occurred in Batman’s world - at some previous point their histories diverged.

Since Judge Dread wasn’t created or published by DC Comics, any of the events in it cannot be canon in DC continuity. Occasionally, characters guest-starring from other publishers in crossovers will be portrayed as being from a never before seen portion of DC’s continuity; but that isn’t practical if the characters are from a universe radically incompatable with the mainstream DC universe. The Infinity Crisis was invoked to, among other things, remove from canon multiple incompatable versions of the future that had been piling up for decades. So in Judge Dread’s case it definitely required that he be from another dimension. Since the writers of Judge Dread frequently play dimensional crossovers for laughs, that fits in with their continuity.