Well of course, in vector apps, there's always a grid (that you can shut off) of dots on the background that you can preset in measurements (I use inches) with Snap to Grid feature as well. Vector doesn't generally set by pixels, since pixels are meaningless in vector, until you are complete then export the file to whatever pixels you want. From the same map design, I can export at any resolution, I usually export at 100 or 300 dpi from the same file without actually changing the physical scale of the map. I use the dot background grid to line up any line grid I wish to place.