Angle from project to true North

[saryyev_m781518]

Hi can anybody help me in figuring out what is the exact value of angle from project to true north? As in the attached pictures my base point shows 15.79°, but on the upper right corner of UI the number is 15°47'25". So, which of these two numbers would be the angle from project to true north? This was the question from Revit knowledge assessment test, and I needed to input the value in decimal form. I would greatly appreciate if someone could clarify this for me.
Thank you.

[Steve_Stafford]

They are the same value but expressed in different units, 15.79 degrees = 15 degrees 47 minutes and 25 seconds (what is displayed on the options bar). If the test expected you to provide a decimal value then 15.79 is that.

[saryyev_m781518]

Steven,

Thank you, you made it clear for me. My guess on the test was actually 15.79 but for some reason I didn't get any score on that answer. As I remember the question
said the value could be written in three decimal form. (as i understand it was an option) but if that's what they wanted, Is that even possible to write in three decimal form? If yes, please let me know where do I get that number? Thank you.

[Steve_Stafford]

You'd have to use Project Units < Angle < increase the number of decimal places to see three instead of two.

That's probably what they were testing you about.

Fwiw, I got to review an early certification test years ago. After taking it I complained about one of the questions because they asked for the area of a room that wasn't tagged. I tagged it instead of going to the trouble of selecting the room itself. The tag showed two decimal places but properties would have shown me three because the tag wasn't tied to the project units. My answer, though correct, was wrong because they wanted three decimal places...and didn't specify that in the question either.

[saryyev_m781518]

Wow, I guess that's exactly what they wanted! I changed the angle units to three decimal places and it turned to 15. 790°. Only when you take a test like this do you understand the true holes in knowledge. Otherwise, on practical basis its somewhat easier to figure out things. I will try to take this test on more time, and if this question will be the same, then my answer will is 15.790°. Thanks a lot, this was very helpful.

[Steve_Stafford]

That's even more annoying then... 15.79 is 15.790. If it was 15.793 I could see why they care. Shorter answer is they want you to prove you know how to get to three decimal places when it isn't. It seems to me that tests are often the test author showing off...

[david_peterson]

Hi Steve, I would actually tend to disagree. Coming from the structural world, I typically went 4 decimal places. If something was going to be 33.3550, that's how I left it.
Reason being I wanted the guys in the field and in the steel shop, that I was that accurate when I designed/drew it; so they should be that accurate when they build it.
When laying out grids on a 4000' radius, it's important for everyone to understand that yes, that was the number that was decided so it's not left up to chance.
The struggle I get into from time to time is when the Architectural drawings don't show that level of care. ie Placing dimensions where they shouldn't be, because it wasn't a controlling dimension and really needed a +/- after it. I've been burned on 3 projects because of that.
In this case I'd say your correct, but I've been told Steel shops can prep steel to 4 decimal places, so take the guess work out of it. Unless you have a perfect pythagorean triangle (3,4,5) you should dimension the length or the angle, but hardly every both.
Just my 2 cents.
But in this case I think the correct answer may lie with the use of Significant Figures. If you actually convert that to decimal degrees the true value should be 15.79028.
15° 47' 25"
= 15° + 47'/60 + 25"/3600
= 15.79028°
So you could ask the testing agent where they got their answer from. Revit is more than capable of being that precise.
Just another observation

[Steve_Stafford]

You're disagreeing with something I don't think nor did I say. My responses and comments have to do with the test...how they asked the question.

It is perfectly reasonable to need/require more decimal places for bearing and angles in a real project.