Pipe Length/Stationing

[b-man]

I have a mathematical anomaly that I am hoping someone can help me resolve.

When labeling pipes, the lengths and stations do not always match. this appears to be related to a rounding issue. for example, the first pipe may start at 0+00 and have a length of 50.69167397’. The reported station in the structure label (using “normal rounding”) is naturally 0+50.69, as anticipated. The upstream pipe has a length of 43.36435901’, resulting in a total length from 0+00 of 94.05603298, resulting in a station of 0+94.06. However, the rounded values of the lengths (c’mon, nobody reports lengths to the 100-millionth) labeled on the pipes (50.69’ and 43.36’) total an expected station of 0+94.05.

I have tried all manners of “rounding” in the label styles, but it always falls down in one situation or another. I have also tried setting in the network and pipe “Feature Settings” for distance to a locked accuracy of 2 decimal places, but that does nto seem to do it either.

So, the question is, is there a way to resolve this issue without having to move one of the structures 0.001’ to resolve the mathematical parallax?

Help?

[Ed.McGriskin]

I don't think there is anything that can be done. I would just chalk it up to being rounding and if someone is raising a stink about 0.01' difference you could always just use a text override to address the rare case. 

Contractor's only ever install pipe to the nearest foot anyway.

[b-man]

I agree, it is a bit asinine, but SOMEBODY is going to do the math and say "You can't add".... perhaps you are right though that there is no simple solution (this is me throwing down the gauntlet to all the smart folks on here...)

The only problem with manually overriding is that it usually winds up being more than one label in a run, and then if you change the alignment or a structure location, you wind up having to run back through this little manual exercise again. Just seems to defeat the point of the automated label.

Seems there should be a way or setting to limit the calculations to using the rounded or truncated values?

[Ed.McGriskin]

I agree with you on the override. Hate using it except if absolutely necessary. 

The issue is not really with the rounding which autocad does but rather how the values are arrived at. One is a sum of lengths and the stationing is based on position relative to the alignment.

[troma]

If somebody tells you you can't add, tell them they can't round.  It simple mathematics, and both labels are absolutely correct.

In this case, if you change your label precision (for pipes and stationing) to either 1 decimal or 3 decimals it happens to 'work' as you would like, but in other circumstances it wouldn't.  If someone is getting too picky with your drawings, turn all the labels to 10 decimal precision and give them a plot.   Maybe that'll quiet them down!

[Joe-Bouza]

It may not be a rounding problem but more a stationing problem. I'm assuming your alignment runs through the center of your structures and pipes and the pipe deflect at the manhole. when an alignment has a kink in it the stationioning can get squirrley at and around the PI. Test it on straight run of pipe vs one with bends. Also, is you lable style lable pipe center line center to center?

A tiny radius at the structure might help?

[BrianHailey]

One of my mantras, "2+2=5 for very large values of 2".

If someone tells you that 2+2=5 is wrong, then you know they don't understand rounding. 2.4+2.4=4.8. Round each one to the nearst integer and you get 2+2=5 and there is absolutely nothing wrong with this.

You can also tell them that 2+2=3 for very small values of 2 (1.6+1.6=3.2).

In other words, 2+2= something between (and including) 3 and 5.