What is the differentiate of "Slope" and "Rolling" for piping mechanical drafting? kindly share your ideas about this please.

Slope is the ratio at which the pipe is to be maintained through out the total line in which it is erected.It is denoted as 100:1, 1000:1 etc. which can be refered from the Isometric drawing.

Rolling is the Offseting of pipe in either vertical or horizontal directon.

Slope is the minor change in the level of pipe which will be mentioned as 1000:1 and etc which specify 1mm change in level of pipe for every 1000mm lenght &  where as rolling means the routing of pipe  in direction other than  East,West,North,South,UP & Down 

slope means process point of view it is mentioned in P&ID. Like 1:250 or A:B. We have to follow the slop for pipes and need to mentioned in ISO. if we walk 250 meters pipes need to down 1 meter from origin.

regarding rolling generally pipe offset vertical or horizontal a the  point of elbow. which is mentioned in ISO by hatch.