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?

http://www.roofhelp.com/roof_slope.htm

In article ,
Harlan Messinger wrote:

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?

That's as good a hypothesis as any. I know my landscaper is confused
about the topic, and consults me on every new job design. Something
about math eludes people.

Back in the stone age when I took a research class in college, the story
was told of a fairly prominent researcher who had sought at length in
vain for a particular statistic. It was the only piece of data lacking
in his otherwise complete paper. So, he made up a number. Fifty years
later, still considered a definitive authority on the subject matter,
his fictitious number was still being quoted by others.

"Harlan Messinger" wrote in message
...
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?

In civil engineering, earth slopes are described as 1-1/2:1, 2:1, 3/1, 4:1,
etc. This means one foot of rise in the stated number of feet. Perhaps
there has been a mistaken use of terminology from one field (earthwork
construction, for example) used in another field such as carpentry where
other expressions are customary.

SJF