Control errors using CRTN
So I did precalcs for a city block that has been surveyed many times. Upon site arrival, the city has wiped out the center line block corners. I had maps that use exterior points to re establish the block corners. I took readings on those exterior points, then did a line station distance stakeout to reset the block corners. Then after those were reset, I performed a localization transformation on the reset points. Decent residuals. Upon checking some other found monuments. I knew something as wrong. I adjusted to the found monuments and completed the job. In the office, it wss discovered that the reset points were NOT at the prescribed distances although perfectly on line between the exterior positions used for reestablishment. Im wondering if the in transformed data was using some scale factor from CRTN. ?
Any thoughts or advice ?
Unless you're within a few miles of a base the CRTN may produce too much error for control work. On top of that you further warped the scale factor and transformation by performing a localization. This is best done with a static network and or total station. An example where quicker is not always better. I would use my 6 static recievers around the perimeter for control network. Then run the TS where multiparth s an issue. Reduce grid to ground if needed. Check record vs. measured to tie in to old datum. Once confident with your control, then stake points.
goodgps you look too young to have 108 posts.
I suggest contacting Dr. Bock at CRTN to help understand the root of your issue. If he can't address it, there are others (users of CRTN) who he can refer you to. I am not going to guess, as it isn't totally clear to me what you did.
Sounds like localizations on top of localizations, seems like that could cause problems.