Drawing Property Lines From Assessor Map

[zzzagman]

Hello,

 

I was given the assignment to draw into the Autocad 2008 the property lines for the parcels in the 283 group on the attached assessor map.

 

I am having trouble drawing the arcs in the lots 7, 8, 9, 1, 19 & 20. I do not understand how the arcs are defined, what is the Radius, the angle and how to find the center of the circle. (I do not want to "trace" over the image, I want to draw it correctly, imputing the surveyor info.)

 

I am assuming that I do not know some basic convention, or that I am missing some information on this sheet that would give me some referrence points.

 

I would appreciate any assistance in this matter.

 

Many thanks. Please feel free to point me to any tutorial or to send me email directly, at zzzagman@gmail.com.

Assessor Map..pdf

[CarlB]

This assessors map does not include sufficient information to accurately draw the lots. None of the radii are given. You should try to get a copy of the plat, which will have all the necessary information. On a few of the arcs along a road you could guess the radius, probably an even 10' increment, see if it gives you the correct arc length.

 

I searched a little and found this plat using the book & page on the assessors map:

http://www.countyofsb.org/pwd/surveyor/rm_pdfs/BK015/R015_016.pdf

 

It includes radii. I see my assumption about them was wrong

[zzzagman]

Hi Carl,

 

Thank you for the posting. It has been very helpful and helped me get the job done. Evidently, I do not know a lot about surveying... Even the fact that you found the surveyor maps all the way from Alaska blows my mind... I didn't even know such info existed, let alone where to find it.

 

Anyway, thanks again.

 

If I may abuse your kindness, I would like to ask a question that is not necessarily related to the previous posting. Rather, I wonder how does one find the center of a curve, if the arc is NOT tangent to the adjacent lines/curves. I imagine it might requre some bearing information for the location of the center, but I wonder how that would be marked on a surveyor map... If you have the time to answer this, or to point me to a tutorial/example somewhere on the net, I would "double" appreciate it.

 

Regards,

 

Z.

[CarlB]

You're welcome. I knew some states/counties have plats avalailable on-line, and stumbled upon it. Being in Alaska was no hindrance

 

If a curve is not tangent, more information is needeed to define it. Usually a chord bearing and chord length are provided; with this you can find the endpoint. Then you can draw an arc knowing start point, end point, and radius.

 

Whaddaya know, found a tutorial right here at CADTutor. Thanks R.K. McSwain!

 

http://www.cadtutor.net/tutorials/autocad/survey-data.php

[zzzagman]

Again, thanks a million!