Bearing Discrepancy

[srousey74V5X]

Please see the attached PDF.

Notice that the bearings are a second different from the 2 different labels. Yes, the linework is connected at the ends. I assume this is a rounding issue caused by one of the labels?

Any ideas on how to resolve?

[brian.strandberg]

Its going to be about how the label styles are defined, and how it is rounding.  I don't think there is a way to diagnose this precisely without having the drawing.

Thanks.

[MichaelH13]

I never knew an arc could have a bearing....

A 1 second discrepancy is not worth worrying about really. It will most likely be rounding in the label.

[rl_jackson]

That's a rounding issue, between the drawn line segment and the calculated bearing of the arc. It's so insignificant that it's not really worth worrying about.  When I see things like this, I generally ignore them and if I need it to read the bearing on the line vs. the calculated bearing on the arc, I edit the curve label accordingly. 

[doni49]

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@MichaelH13 wrote:

I never knew an arc could have a bearing....

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Chord Bearing (the line connecting the ends of the arc would be the chord).

[ChicagoLooper]

@srousey74V5X 

I agree with @rl_jackson 

Looks like you're splitting hairs. When drawing linework by bearing, what precision did you (or the original author) use? Were the 'seconds' whole numbers? Or did the seconds have decimals?

Both bearings below will result in 33°6'35" when rounding to the nearest whole second and this is in consideration of 0°0'.98" discrepancy.

33°6'35.49"

33°6'34.51"

BTW, this post could easily be titled Should We Use Decimals in Seconds When Displaying Bearings?

Furthermore, a discrepancy of 0° 0' 0.02" can happen like this:

33°6'35.51" will round up to 33°6'36"

33°6'35.49" will round down to 33°6'35"

[srousey74V5X]

I'd like to thank everyone for the replies.

Yes, I know 1 second isn't going to matter in the big picture. Nevertheless, there is a discrepancy. I used the Bearing-Chord&Radius-Arc label style to label the lines/curves in my boundary, then I used the Parcel General_Legal_Description_for Parcels to create a legal description of the property. To make matters worse, the client is the one that discovered the discrepancy between the drawing and the legal description. 

Obviously, that is not good. Does anyone know how to fix it?

[MMcCall402]

Could you post a little cad file with an example of this behavior?  

[srousey74V5X]

Drawing attached.

[MMcCall402 · Accepted solution]

Zoom into the north end where the chord line meets the curve .... they don't match.  It's a very small amount, 0.00013, but that's where the discrepancy is coming from.

[srousey74V5X]

But, if they're different endings, why is the software giving them the same Grip point? If you select both, there is only 1 grip? That's the whole reason I thought they were together.

[MMcCall402]

It is strange.  If you select each object by itself you get two different grips.  If you select both of them at the same time you only get one.   I can only guess that it falls below some programming threshold.

[BrianHailey]

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@srousey74V5X wrote:

But, if they're different endings, why is the software giving them the same Grip point? If you select both, there is only 1 grip? That's the whole reason I thought they were together.

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That's a great question and one I don't have an answer for. They definitely act as if the ends are coincident but when I edit the line and snap it to the ends of the curve (or the curve to the ends of the line), the labels now match.

[BrianHailey]

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@MMcCall402 wrote:

It is strange.  If you select each object by itself you get two different grips.  If you select both of them at the same time you only get one.   I can only guess that it falls below some programming threshold.

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I never got two grips but the order you select the entities determined where the grips are. Very strange indeed.

[srousey74V5X]

Well, thank you all for showing me what a complete idiot I am. LOL. It's a bit embarrassing to make such a simple error, but I guess I've learned not to hold complete faith just in the grips representing the ends of multiple objects. 

[BrianHailey]

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@srousey74V5X wrote:

Well, thank you all for showing me what a complete idiot I am. LOL. It's a bit embarrassing to make such a simple error, but I guess I've learned not to hold complete faith just in the grips representing the ends of multiple objects. 

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Don't be hard on yourself. This program likes to make us all look like chumps at some point. If you go through the archives of this group, you'll find me posting questions with very similar responses. Take the new knowledge and go forth and be excellent!

[ChicagoLooper]

@srousey74V5X 

For all we know, the linework was originally 'surveyed' 110 years ago using a compass pulled out of someone's pocket and non-battery powered instruments carried on the back of a horse. As far as a survey, the accuracy and the precision of those metes and bounds are still enforced today. 

Had the original surveyor used two (or more) decimals in their seconds, I doubt you'd be having this discussion. Obviously, the seconds portion in his original survey does have more accuracy but it's RECORED in the property tax books as rounded to the nearest whole second. The Recorded doc won't be changed but a newer survey may document a difference, Legal vs. Measured, where the measured  is enclosed in parentheses and the Legal remaining as-is.

<<Although the 'recorded' distance and bearings won't (shouldn't) change in the Legal description, a newer drawing may note higher precision. Modifications to the legal description will affect not only the current property owner but his next door neighbor too since many parcels share a common border and may affect a mortgagee (bank) who has a lien on the property 'described' in the mortgage.>>

The Recorded Legal Description must be taken at face value and not be subject to our high-tech AutoCAD drawing standards we typically use today. If your metes and bounds survey has many segments, then AutoCAD may expose bearing discrepancies of +/-0.4900 degrees at one or more 'turn.' You'd hope the total overages and the total under-ages would cancel each other out but the reality is the last segment won't return to the POB (point-of-beginning) leaving a gap in the Bounds which will leave you wondering which segment, or segments, to adjust and by how much?

[srousey74V5X]

This is all new. I created the curve. I then generated a legal description using General_Legal_Description_for_Parcels and the client noticed the bearing of the curve in the legal didn't match the bearing from where I had annotated it in the drawing. At that point, I drew a line from 1 end of the curve to what I thought was the other end and annotated it and got 2 different bearings as shown.

You're not going to see a survey from 110 years ago with a bearing out to the second (much less 2 or more decimals) and distances down to the hundredth of a foot.

[ChicagoLooper]

@srousey74V5X 

<<...At that point, I drew a line from 1 end of the curve to what I thought was the other end and annotated it and got 2 different bearings as shown.>>

Huh? So you drew it incorrectly and got the wrong label?

The title of your post is Bearing Discrepancy but your label is actually reporting exactly what you drew.

[srousey74V5X]

The bearing in the legal description created didn't match the bearing of the label.

I just did another quick legal description, and you can see the bearings in the description match. That's from the exact same linework that's showing a difference of 01".