Every single place on-line that I can find that describes a slope ratio defines it as the ratio of drop to horizontal distance (rise-to-run ratio), and then gives an example of the exact opposite--for example, a
2:1 slope ratio is illustrated by a one foot rise for a two-foot run. Is it that there was a mistake in one landscaping textbook 50 years ago that got perpetuated, so that now everyone in the landscaping business is confused?