Usually moderates can be either party, the ones willing to work together from both sides, so in the center. Progressives are generally considered to be the left-leaning democrats.
I could be mistaken though, I've been trying to avoid politics recently....
>>miriam+(OP)
In San Francisco the Republican Party is marginal (and broadly despised by the electorate), so you can think of the "progressives" vs. "moderates" as sort of the local version of two parties, mostly within the Democratic party.