HI! How do you guys approach drawing the grade line - the NCARB practice exam shows a swale and ridge, but the contours do not cross the cut line. Dorf advises NOT to interpolate the grade and instead to draw it straight across. On several posts here, i've seen examples where some amount of interpolating was graded as a pass. Advice? Experience? What's the rule on this???

EDIT - I rewatched the Dorf video, and realized that his cut line goes through the 120 contour and the 125 contour, but the NCARB example does not. So, it's not apples to apples. Oh well. I still find his advice on the video to be confusing.

Are you talking about the sample passing solution in the guide? If so, look again. The section line DOES touch those contours which causes the "swale" and "ridge". They don't interpolate. You shouldn't either.

little12 wrote:Are you talking about the sample passing solution in the guide? If so, look again. The section line DOES touch those contours which causes the "swale" and "ridge". They don't interpolate. You shouldn't either.

So, if the contour TOUCHES the cut line (even if it doesn't cross), it counts as a point on the grade line, and that is not interpolating. Is that correct? Testing Saturday!

berkberkberk wrote:So, if the contour TOUCHES the cut line (even if it doesn't cross), it counts as a point on the grade line, and that is not interpolating. Is that correct? Testing Saturday!

Yes, that is correct.

yes. if it's touching it, then it's crossing it.

If it helps, just look at the section line and identify all the places it "touches" contours. Don't think of them as crossing. You're just finding points and dropping them down to the section.

Got it. Thanks everyone.