i need to plot profile of some levels. how do i go about it?

Answer 1

It sounds like you are making an elevation profile from a topographic map? If so...

Find out what the contour interval is..it will say somewhere on the map. This is how many feet (or meters) change in elevation for each contour line. Maybe something like 10 ft

As you go from point a to point b keep track of how many contour lines you pass, how close they are together. If you know what elevation each line stands for it will not be difficult to draw it on the elevation profile.