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Reporting Acreage

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(@krj2004)
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Can someone explain to me how to determine how many places beyond the decimal to show when reporting acreage on a survey in Texas? For example, should a rural tract be reported as 40.216, 40.22, or 40.2?

 
Posted : 12/11/2012 1:57 pm
(@ragoodwin)
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I would say refer to the Manual of Practice -Standards -Section 0.5 "Calculation of area" page xiii in my manual.
I dont like 3 places- - we will get something different tomorrow;-)

 
Posted : 12/11/2012 2:19 pm
 vern
(@vern)
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Depends on where you round your square feet. 😛 I

report areas as: "Containing x,xxx square feet (x.xx acres more or less)." I put the emphasis on the square feet which is what most urban sales are based on anyway. Occasionally you will get the client or attorney who wants to see more decimal places and I will throw them in but maintain the same format emphasizing the square feet.

 
Posted : 12/11/2012 7:18 pm
(@bill93)
Posts: 9834
 

Unless there are rules to the contrary, for a rectangle you should give the same number of significant figures as the side with the fewest significant figures.

In general, based on your measurement tolerance find a max and min area consistent with the measurements and give one questionable digit.

 
Posted : 12/11/2012 7:29 pm
(@randy-hambright)
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I usually report acreage to 0.00 in a rural setting and 0.000 in an urban setting.

Never to 0.0.

If you are going to mention square feet, do the math and make sure that it works with the acreage to the tee or some title company gal or an attorney will surely be calling one day.

I have seen a few older subdivisions around here that is reported at 0.0000, now that just dumb.

Randy

 
Posted : 13/11/2012 5:49 am
(@perry-williams)
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My mentor always told me to truncate the acreage and never to round up.

 
Posted : 13/11/2012 5:52 am
(@ianw58-2)
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Thank you, Bill! That's the only professionally justifiable answer.

 
Posted : 13/11/2012 6:15 am
(@roadburner)
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> I have seen a few older subdivisions around here that is reported at 0.0000, now that just dumb.
>
> Randy

I always report square feet to the nearest foot, then acres to 4 decimals, followed by more or less. Reporting acres to only 3 decimals is the equivalent of saying "containing xxxx square feet, or x.xxx acres, give or take 21 square feet". That seems pretty silly to me.

 
Posted : 13/11/2012 8:51 am
(@randy-hambright)
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Hey Road,

I am talking about very rough, large acreage subdivisions.

If I come up 0.0001 short, they want to know where the rest of their property is.:-P

Randy

 
Posted : 13/11/2012 9:36 am
 jaro
(@jaro)
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One way of looking at it is 0.001 acre is 43.56 sf. If you can easily assume any line can be off by .01 feet left or right (which is a pretty easy assumption) then a tract with a perimeter of 4356 linear feet could easily render .001 acre error. A perfectly square tract with a perimeter of 4356 linear feet would be 27.22 acres.

Personally I can't survey a 27 acre tract and be confident in the location of every line within .01 feet. I usually cut it off at 10 acres more or less. Smaller tracts get 3 decimal places. There have been exceptions.

James

 
Posted : 13/11/2012 10:33 am
(@kris-morgan)
Posts: 3876
 

The rules state to the least significant digits. Many will show you here and argue about that.

For me, three decimal places up to 2 acres, 2 decimal places up to 900 acres, 1 decimal up to 2000 acres, nearest acre after that, and I've only had two jobs where that was ever an issue. 🙂

 
Posted : 13/11/2012 11:13 am
(@kris-morgan)
Posts: 3876
 

Road

You must be joking right? You can't accurately measure to the .0001 acre, and if I bump your rod 0.01', it ain't right again.

Reporting to x.xxxx acres is like saying, "I'm a dork who doesn't understand when the math doesn't mean anything"

 
Posted : 13/11/2012 11:16 am
(@roadburner)
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Road

> You must be joking right? You can't accurately measure to the .0001 acre, and if I bump your rod 0.01', it ain't right again.
>
> Reporting to x.xxxx acres is like saying, "I'm a dork who doesn't understand when the math doesn't mean anything"

Do you report square footage to the nearest square foot? Or do you round it off to the nearest 0.001 acre equivalent? (43 square feet)

 
Posted : 13/11/2012 11:26 am
(@kris-morgan)
Posts: 3876
 

Road

First, I don't report square footage. It's silly. Second, I typically work with tracts from 100 to 3000 acres and showing three decimals is silly on those also. Hell, at the 4th decimal place, you can't even match yourself without lying. Do you realize that?

 
Posted : 13/11/2012 11:31 am
(@adamsurveyor)
Posts: 1487
 

We all create descriptions that have calls to the nearest second, and distances to the nearest hundredth (maybe not "all" of us, but a whole dang lot of us). That legal description is at a 'higher' order of precision, usually, than measured. But no one has a problem calling out bearings to the nearest second.... So why do we worry about acres so much? If you had 43,564 square feet maybe you should round it to 43,600? You're doing the same thing with acres if you don't use 1.0001 acres (5 digits).

But I don't care. I use the square feet at the nearest square foot (even though I don't measure that precisely; if someone ran my description that's what they would get, and I have a hard time taking a perfectly good number, and rounding it to the 10'). I use acres to the nearest thousandth. (40.123) and square feet to the nearest ft²

To the guy that said to always round down. What if your client had a minimum acreage he was supposed to have according to some regulation? Like 1 acre minimum and you measured 0.9998, are you going to report less than his minimum?

 
Posted : 13/11/2012 11:31 am
(@adamsurveyor)
Posts: 1487
 

:good:

Bill's right on. 40.22 acres if the shortest side had four digits in it; 40.216 if the shortest side had 5 (three to the left and two to the right of the decimal if you're reporting to the hundredth).

for 41,123 square feet, would be either 41.120 or 41,123 square feet (0.9941 or 0.994 acres respectively).

Calculating area from the bearings and distances is basically the rule of significant digits for multiplication. the answer is to the same order of precision as the weakest multiplier.

 
Posted : 13/11/2012 11:49 am
 jph
(@jph)
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I agree. I think that the significant figures/decimal places only relate when you're using the same units. So lot dimensions to the hundredth of a foot, yield an area to 0.01 sf.

I think that when you do a simple math conversion to acres, you can legitimately go as many places that equal that (not that we would).

But as Kris wrote, you don't need acres to 0.00001 if you're dealing with 100+ acres.

 
Posted : 13/11/2012 12:20 pm
(@roadburner)
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Road

> First, I don't report square footage. It's silly. Second, I typically work with tracts from 100 to 3000 acres and showing three decimals is silly on those also. Hell, at the 4th decimal place, you can't even match yourself without lying. Do you realize that?

Whatever works for you. If we were doing 3000 acre tracts, we wouldn't be reporting areas in square feet either. :-/

 
Posted : 13/11/2012 12:48 pm
(@ianw58-2)
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And feet are the same as feet?

http://www.wellesley.edu/Astronomy/kmcleod/Toolkit/sigfigs.html

Look down toward the bottom for examples using square feet and acres

[sarcasm]And we're supposed to be experts on measurement...[/sarcasm]

 
Posted : 13/11/2012 1:13 pm
(@dougie)
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> My mentor always told me to truncate the acreage and never to round up.

NEVER?

Never is a long time.

So if it's 99.9 it's never 100?

I understand the logic but I never say never...;-)

 
Posted : 13/11/2012 1:16 pm
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