In the case of performing a least squares adjustment on multiple interconnected tranverses, where the points traversed through and interconnected are centerline road monuments controlling a boundary or subdivision monuments, is a minimally constrained adjustment sufficient? The goal is to match the existing basis of bearings of a recorded plat (with ground distances), and to ensure that the precision of my measurements is acceptable. As far as minimal constraints, I am referring to holding an arbitrary coordinate and the basis of bearing on a recorded plat. All measurements have been performed with a total station.
Thanks
Are you trying to adjust your field survey measurements at the same time as aligning your field points to the record plan information? That is how I am reading what you described, and that is not a correct use of least squares adjustment. You should not be mixing your measurements together with record dimensions.
Peter Lothian - MA ME, post: 397871, member: 4512 wrote: Are you trying to adjust your field survey measurements at the same time as aligning your field points to the record plan information? That is how I am reading what you described, and that is not a correct use of least squares adjustment. You should not be mixing your measurements together with record dimensions.
Peter thanks for the reply. I am not trying to mix my measurements together with the record dimensions. What I am trying to do is adjust my traversed field measurements between boundary monuments while holding the basis of bearings on a recorded plat. The record measurements will remain the same. My thinking ,when I mentioned using a minimally constrained adjustment (as in holding an arbitrary coordinate fixed and the plat basis of bearings) was to keep any possible rescaling of the distances (however minor it may be) from occuring when using a fully constrained adjustment. I hope this explanation makes sense.
Thanks
I would recommend "Transform" by Primacode. It will allow you to do what you are trying to do...
What software are you using?
lmbrls, post: 397883, member: 6823 wrote: What software are you using?
I'm using StarNet.
Yes, I have done exactly what you describe in StarNet. You assign one arbitrary coordinate and one bearing from a Plat. The Plat distances (and the rest of the bearings) have no impact on the adjustment. We usually combine GNSS and conventional and adjust into Grid but sometimes in heavy forest that is not practical or timely enough.
Jim in AZ, post: 397879, member: 249 wrote: I would recommend "Transform" by Primacode.
I think just holding a point and bearing is what you should do FIRST to adjust your redundant measurements.
THEN you can free the fixed point and bearing and do something like Primacode with your adjusted data versus the plat to find a shift, scaling, and rotation that best fits the two systems together.
http://www.primacode.com/transform.htm
I used Starnet for that very purpose. It checks your data and rotates it to a record bearing with virtually no effort.
The only difference is what I describe the process as. My main purpose is analysis, not adjustment. I've found that calling it analysis reminds us of what the exercise is about...
Thanks for the replies and suggestions everyone. They are much appreciated. Pertaining to Primacode, it seems like a good way to identify potential and isolate potential discrepancies between field and record. I'll download the free trial and take a look.
Cheers.
I believe the function is to identify and remove error. After that process is complete then I compare my chain to the previous surveyors chain by reporting record and measure. I do not subscribe to the motion that I an trying to adjust my measurements to fit the record plan. The retracing surveyor does not changes the lines run and marked upon the ground by reporting the results of the retracement survey. David Karoly outlines the process perfectly.
Primacode looks like a very good tool when attempting to fit missing map corners between many found controlling corners.
