Redneck350

Thanks for the info. Isn't there a keystone or something somewhere where the major lines are taken from? Haines resurveyed his property some years ago. Some of the new survey lines appear to start at the same place then angle off. Others are way off in the hundreds of feet in both the North and West directions from the old survey lines. Your job must be challenging at times.

Is there an accuracy "standard" such as inches or feet? I realize accuracy is closer in cities andr towns because there are many points to take measurements from. What about what we're talking about, vast expanses of land where you must cut survey lines?

Accuracy standards are complex mathematical solutions not units of measurement. A simple explanation of calculating accuracy is determining ratios of calculated error in closure, both vertical and horizontal. If I surveyed a 20 acre square parcel, it would have a perimeter of 3,733.52 linear feet. If I ran a closed traverse and turned back into my beginning point there will be accumulated error. The distance error between the point as measured and the point as calculated is divided by the perimeter distance to obtain a ratio. Keep in mind that this is a little over-simplified. The ratio determines the horizontal accuracy. If a survey has an error of closure of 1:10,000 it essentially means you will accumulate 1' of error in every 10,000' surveyed. It is not simple to explain.

Angular error is determined by comparing the sum of all interior angles turned in a traverse compared to the geometric rule where (N - 2) x 180 = the sum of all interior angles, where N is the number of sides. A four-sided figure would have an interior angle sum of 360 degrees. If my field angles totaled 359 degrees 59 minutes and 35 seconds my angular error is 25 seconds or 6.25 seconds per angle station.

Here is a document with some explanations:

I can tell you the age of the survey has little to do with accuracy. An old transit and chain survey is no less accurate than one done by GPS. It all relates to the care taken in performing the work.