I am in the process of starting to "plan" a possible addition.
I realize they are not always accurate, but I am trying to locate the last of my 4 corner pins.
From my deed and also the county property map, I have tried to lay it out in a cad program I use.
The corner pin I can not locate is part of the Arc in my property.
My deed matched the property map except for 1 angle (deed says 98.55 and property map says 98.95) so the arc width/chord ends up showing 87.384 or 86.598.... (.785' difference). When I draw it in CAD.
I cant seem to calculate what the correct distance between my 2 pins (arc width/chord) should measure based on the following:
R=875.00' Delta "triangle" 5.46 L=88.07'
Every calc tool I tried, I can seem to get those 3 dimension to equal out to each other.
Not sure what I am doing wrong....but what should my actual arc width/chord be?
Thank you!
R=875.00' Delta "triangle" 5.46 L=88.07'
For a curve with that large a radius there isn't likely to be a whole lot of difference between the arc length and the chord length. In this case the chord length is 88.03'.
The delta angle is (probably) 5°46', not 5.46°, which may be the source of your calculation issue.
Can't tell what you're talking about. Post a copy of the deed description.
With the given radius and arc length, the delta is 5 degrees 46 minutes and the chord length is 88.03'. You can take half of the arc's delta and add or subtract it to the incoming tangent bearing together with the chord distance to get to the opposite end of the arc or point of tangency. Adding the other half of the delta will get you onto the outgoing tangent bearing. Remember adding or subtracting DMS you must first convert to Decimal degrees, do your addition or subtraction, and then swap back to DMS.
Just because I'm paranoid, doesn't mean they aren't out to get me.
98d55' and 98.95d are essentially the same thing.
@mightymoe yes but at the end if a 112' line it ends up being about 8" difference to the corner I am trying to locate.
Because I am new to the forum it will not let me attach a photo/drawing or I would have done that. thanks
Because I am new to the forum it will not let me attach a photo/drawing or I would have done that.
You can now. 😊
The difference between 98d55' and 98.95d would not move the end of a 112-ft. line 8", if that's what you mean. You may have a decimal error there. Can't tell for sure. Once there's a drawing up, it will be possible to make more rapid progress.
There is always the option of hiring a land surveyor to find that pin for you. If your putting an addition on your house that seems like an important first step.
This should help, I am just showing what happens when I lay it on in my CAD software.
Your CAD plot is hard to read, but it looks like there may have been an input error. Neither of the figures given for the chord of the curve is correct.
The drawing you have posted looks like a piece of a subdivision plat. The "property map" you mention must be something else; perhaps an online GIS map. The subdivision plat is the proper source for lot dimensions because it's part of the legal records of your property. This one looks OK.
I ran a closure on the lot from the dimensions given on the plat drawing, putting in the three straight sides and the angles between them. The closing distance from the lower left to the upper left corners, i.e. the chord of the curve, calculates to 88.03.
As Norman OK and Williwaw have said, 88.03 is also the computed chord from the curve data, and is not much different from the arc distance of 88.07.
The chord is computed by the formula 2 x R x sin Delta/2. That is, you take the central angle of the curve, 5d 46'. That's known as the Delta angle and is represented by the Greek letter Delta, which is a triangle. You divide the Delta angle by 2. Then you take the sine of that and multiply it by the radius, 875.00. Then you multiply that result by 2.
You might find it useful to get hold of a scientific calculator with trig functions. The formulas needed here aren't very complicated. If you're using any sort of online calculator, it's hard to tell whether it's using the correct formula for what you're trying to do.
You are treating the angles as decimal degrees. They are expressed as degrees and minutes. There is a big difference between "98 degrees 55 minutes" and "98.55" degrees. Same with the other angles. The record dimensions close virtually perfectly.
I actually got the exact same solution as the OP so either I'm misreading the plat or some of the dimension data is wrong.
@norman-oklahoma His notation is a whacky mix of DMS and decimal degrees but the numbers themselves seem to be right.
OK, what in the hell is carlson doing here...
I draw the north lot line cardinal east west at 120.71 feet, make a duplicate of that line and rotate it about the east end of the line positive 86d51'00" and then when I label the angle between the 2 lines it's showing 86d30'36" instead of 86d51'00"...
Don't tell me for rotations it goes into decimal degrees mode or something.
OMG IT IS. WHAT IN THE ACTUAL HELL!
So yeah OP your cad must be doing the same thing mine is where it's wanting decimal degrees for the rotation. The plat dimensions actually check out perfectly like Norman said.
The infuriating thing about the program I'm using is it shows a couple different angle values in DMS inside the rotation UI. Talk about misleading as hell! Here's a picture of what I'm seeing with the misleading stuff highlighted in orange:
Did some additional testing and discovered if you enter the angle as 86d51'00" then it works fine but if you do the "decimal way" of entering DMS like 86.5100 (which is the way you enter an angle in the line by bearing routine) then it assumes you're entering decimal degrees. Ugh, this kind of thing annoys me so much when it's not consistent inside the software. I realize it's trying to be user friendly, but I think this is actually worse than forcing the user to enter the angle only 1 way.
okay thanks for your help.
Just to be clear "98 degrees 55 minutes" and "98.55" degrees.
98 degrees 55 minutes is the same as (98 + 55/60=.9166..... ) 98.9166 degrees?
I think that is the part of my confusion, my software only allows degrees.
Thanks very much.
Looks like that was my problem....I had the other angle at 86.51 degrees instead of 86.85 degrees now the 88.03 dimension shows correctly as well.
@jamesk besides the other possible decimal vs dms confusion, that doesn't look like an 875' radius on your arc
This should help, I am just showing what happens when I lay it on in my CAD software.
Seemed to close out well in my attempt. That arc label lists chord length, Az & radius
