RA2009 and slope units?

[angus.110169]

I was all excited when they announced that slopes can now be reported as ratios! However the reality is something that is not usefull (to us anyway). I cannot find any documentation on the new Project units for slope, has anyone explored them?

My main contention is that ratios are reported as ?:10 or ?:12 - who uses these ratios?

If we report a slope it is as 1:5 , 1:8 etc... am I missing something?

[sbrown]

By defination a ratio doesnt need any specific units. That is a common way for us in America to report Ratios 1:2 = One Vertical Unit to Two Horizontal. So a 1:1 = 45deg. 1:2 = 22.5. etc. its a nice way to break a slope down for a contrator to layout a roof.

[angus.110169]

mmmm... not really convinced. I understand ratios, however we always use the 1 in ?? format. Your examples also use this format -This option is not available. They do have however the ?? in 10 or ?? in 12 option (this is what I don not understand - who uses these?)

[LRaiz]

1:2 = One Vertical Unit to Two Horizontal. So a 1:1 = 45deg. 1:2 = 22.5. etc.
Sorry, but my calculator says that 1 vertical to 2 horizontals corresponds to 26.566 deg. :)

[atbergma]

mmmm... not really convinced. I understand ratios, however we always use the 1 in ?? format. Your examples also use this format -This option is not available. They do have however the ?? in 10 or ?? in 12 option (this is what I don not understand - who uses these?)

In the US we use ?:12, (because we're too stubborn to switch to metric, still on imperial). But usually just for roofs. For ramps, etc., we use 1 : ?? as well.

[sbrown]

Sorry, but my calculator says that 1 vertical to 2 horizontals corresponds to 26.566 deg. :)

I was just dividing 45 in half, you are right.